[amsat-bb] Re: G-5500 Rotor trouble

[Art McBride]

HI all,
 Small motor capacitors can be found 2 Grainger, and McMaster Carr. These
are run capacitors and are rated for continuous duty. 

Art,
KC6UQH  

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of N1HOQ
Sent: Sunday, May 03, 2009 10:22 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] G-5500 Rotor trouble

Hello group,
Well, looks like I have to crack open the case. I swapped the AZ and 
EL cables with the EL rotor, and no luck, same result. Still making the 
click noise when engaging the UP control, the motor(?) still hums away 
(sounds like 60 Hz), but no movement. Last resort now , open it up and 
hope to catch all the bearings, hi. Since it seems Yaesu wont sell the 
capacitor sans motor, are there any know sources, or just look at 
Allied, Mouser etc.?
Thanks for the help -
Shawn N1HOQ.

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[amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ

[Art McBride]

One important feature of circular to circular antenna reception is the 30 dB
of rejection of signals that are opposite polarity from ground and building
reflections that will cause QSB on linear antennas used for reception. If
you are 30 miles out to sea this is not a concern.
Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Matthias Bopp
Sent: Sunday, May 17, 2009 7:38 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ

Hi Luc,

a linearly polarized antenna on a satellite means, that you will see
different polarization at different times and different locations on
Earth. Assume the satellites transmit vertical polarization but "tumbles"
then the polarization you are receiving is always linear but can vary
between vertical, diagonal, horizontal ...
Therefore it is better if the satellite and the station on earth both use
circular polarization. If this is not possible due to constraints on the
satellite I think it is still better to have a circular polarized antenna
at my station as the losses due to varying linear polarization will always
be only 3dB and thus no strong fading due to polarization will accur.
Please note that a tumbling satellite will most likely still generate strong
fading as the antenna on the satellite will never have a perfect
omni-directional behaviour.

Best regards

Matthias   DD1US

www.dd1us.de


-Ursprüngliche Nachricht-
Von: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] Im
Auftrag von Luc Leblanc
Gesendet: Sonntag, 17. Mai 2009 14:09
An: amsat-bb@amsat.org
Betreff: [amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ

On 16 May 2009 at 17:27, Roger Kolakowski wrote:

A part of my mystery is solved WiFi and WiMAX I am not a big fan of WiFi as
i have some security concern but i discover that i don't have 
the best antenna for 2.4 and fiddling with it is not an option. A true 2.4
is in the mail to replace it and with 2 antennas now i will be 
able to install them to have vertical and horizontal polarisation and i will
see if there is some improvement at 2.4ghz when switching 
between them. Nobody answer me back regarding the S band linear "not
circular" AO-51 antenna but the fades are probably due to some  
antenna blocking than anything else. On the last S band session me and Clare
VE3NPC noted that the fades does not happen at the same time 
on our respective QTH there is surely not some selective circular
polarisation path?

> This was probably just a typo; if so, pardon the reply...
> 
I was mixing both...hi 
> 
> Wi-Fi and Wi-Max are different things.  An antenna designed for Wi-Max
> may not operate very well, as you describe, on 2.4 ghz.  Wi-Fi's
> 802.11b/g is on 2.4 ghz (channel 1 is right on top of our allocation),
> so a properly designed Wi-Fi antenna could be good for 13cm Ham
> applications.
> 
> >
> Enjoy the new toy,
> 
> Greg  KO6TH
> 

Some experimenting to come on the next S band session.
 
"-"


Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE

 

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[amsat-bb] Re: eggbeater rx performance

[Art McBride]

Eric,
A Quadrifilar Helix antenna will meet your needs, and if you choose 1
wavelength, 1 turn design you will have a greater gain at the horizon than
at the zenith which is what you need to compensate for the change in
satellite distance to the observer over the entire pass. 
It is also circular giving excellent rejection to ground and building
reflections that cause QSB. The designs were developed by C.C. Kilgus MSEE
in the mid to late 60's. Designs vary from 1/4 Wave, 1/4 turn to 1 wave
length, 1 turn. His work was published in the December 1970 Microwave
Journal beginning on Pg 49. 

Art,
KC6UQH  

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Eric Fort
Sent: Friday, May 29, 2009 6:17 PM
To: Amsat BB
Subject: [amsat-bb] eggbeater rx performance

I/m interested in the possibility of using oscars 27, 29, 50, 51, and 52
without using rotors or directional antennas and maybe while mobile.  Uplink
seems not to be a problem as one can always QRO to a level where the
satellite sees an apropriate signal level that is enough but without robing
power from other transponder users.  On recieve though you still gotta be
able to hear 'em to work 'em.  Is an eggbeater and a preamp enough to hear
decently or is there another (better) way?  Is working mobile and/or without
directional antennas even practical?  what's the best way to do it?

Thanks,

Eric
AF6EP
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[amsat-bb] Re: FT-847 vs IC-910

[Art McBride]

To All,
Once the phase noise of local oscillator has been addressed the IF filter
becomes the next most important element in the receiving system for audio
clarity. 
Having a flat amplitude response in the filter pass band gives a clear
quality to the voice. Most ceramic filters and some crystal filters have
poor pass band responses leaving the audio on the muddy side. Collins
mechanical filters have for several decades been the benchmark for receiver
IF filter technology. 

SDR has eliminated the need for IF filtering at the expense of poor image
responses in cases where high level signals are present in adjacent
channels. SDR works best in satellite and cell phone environments where
signal levels are controlled either by distance or minimum power necessary
for communications. 

Amateur radios of the future may emulate cell phone power control
technology, but until that is widely in use, a hybrid system with a roofing
filter and SDR IF currently offers the best performance.

Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Alan P. Biddle
Sent: Saturday, May 30, 2009 12:29 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: FT-847 vs IC-910

I would also strongly recommend better filters than the stock ceramic
filters to do a comparison.  When I bought FT-847 in 1998, Inrad did not
have compatible filters, so I bought the Collins mechanical filters which
were available.  I did not do extensive testing, but the HF reception was
remarkably better than the stock filters.

Alan
WA4SCA



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[amsat-bb] Re: Re eggbeater performance - mobile

[Art McBride]

Bob,
It also has a null on an overhead pass.

Art, KC6UQH.

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob Bruninga 
Sent: Saturday, May 30, 2009 5:19 AM
To: mikehooles; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Re eggbeater performance - mobile

> For mobile work on AO27, SO50, AO51 
> a 2 metre quarter wave whip is all 
> you need... to work the LEO's mobile
> and the satellite is 15 degrees or 
> more above the horizon,

Absolutely, For a 19.5" whip in center of roof:

1) Has 5 dBi gain above 20 deg on 2m
2) Has 7+ dBi gain above 30 deg on 70cm
3) Is an omni
4) does not sacrifice 3 dB for circular
5) Above 25 deg, satellite is 6 to 10 dB closer!
6) works the birds solid for the center of high passes
7) Simplicity at its best!

Read about it: www.aprs.org/rotator1.html

Disadvantage:  The only disadvantage is TIME.  On the above web page you can
also see that satellites spend 70% of their daily pass times below 25
degrees.  BUT!  For those best passes in the morning and the evening (or
whenever) you can make solid contacts while mobile for about 5 minutes.

Also note, that you do NOT need any tracking program to predict passes.
AO51 schdule repeats evry 5 days for example.  Just write down the CENTER
pass of the morning and evening for each day for 5 days.  Update those 10
times on a small 3/5" card on the dash about once a month or so will predict
all passes whenever you are mobile.  There will be a pass 100 minutes
earlier and 100 minutes later each day too.  So you can predict all 6 passes
a day from those same 10 times.

See how: www.aprs.org/MobileLEOtracking.html
 
Bob, WB4APR
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[amsat-bb] Re: Re eggbeater performance - mobile

[Art McBride]

Bob,
 It is only significant if you are in QSO when it happens, but needs to be
listed when comparing antenna types.

Art, KC6UQH.

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob Bruninga 
Sent: Saturday, May 30, 2009 11:21 AM
To: 'mikehooles'; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Re eggbeater performance - mobile

> It also has a null on an overhead pass.

But that is quite insignificant.  Looking at the gain plot of a 3/4 wave
vertical (the 19.5" whip on 70cm) it is only down say 6 to 10 dB above 85
degrees.  BUT the satellie is 10 dB or more closer when it is above 50
degrees which more than makes up for any loss of gain straight up.  see
plots on 
www.aprs.org/rotator1.html  

But yes, there can be a complete fade when it is perfectly directly overhead
(extremely rare).  But since the satellite is only above 50 degrees only 5%
of the time, it is only above 85 degrees only 1/8th of that 5%, or much less
than 1% of all access times.  Again, losing less than 1% of access time due
to a possible less than 1% chance of a fade is nothing to be concerned
about.  Just 2 cents worth...
 Bob, Wb4APR

>> For mobile work on AO27, SO50, AO51 
>> a 2 meter quarter wave whip is all 
>> you need...
>
>Absolutely, For a 19.5" whip in center of roof:
>
>1) Has 5 dBi gain above 20 deg on 2m
>2) Has 7+ dBi gain above 30 deg on 70cm
>3) Is an omni
>4) does not sacrifice 3 dB for circular
>5) Above 25 deg, satellite is 6 to 10 dB closer!
>6) works the birds solid for the center of high passes
>7) Simplicity at its best!
>
>Read about it: www.aprs.org/rotator1.html
>
> Disadvantage:  The only disadvantage is TIME.  
> On the above web page you can also see that 
> satellites spend 70% of their daily pass 
> times below 25 degrees.  BUT!  For those best 
> passes in the morning and the evening (or
> whenever) you can make solid contacts while 
> mobile for about 5 minutes.
>
> Also note, that you do NOT need any tracking 
> program to predict passes.  AO51 schdule 
> repeats evry 5 days for example.  Just write 
> down the CENTER pass of the morning and 
> evening for each day for 5 days.  Update 
> those 10 times on a small 3/5" card on the 
> dash about once a month or so will predict
> all passes whenever you are mobile.  There 
> will be a pass 100 minutes earlier and 100 
> minutes later each day too.  So you can 
> predict all 6 passes a day from those same 
> 10 times.
>
> See how: www.aprs.org/MobileLEOtracking.html
> 
> Bob, WB4APR

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[amsat-bb] Re: Another satellite-receiver option

[Art McBride]

Luc,
 When using a preamp in any metropolitan area a band pass filter is needed.
Helicoil types are very good for VHF. DCS makes them or build one out of the
RSGB Book. 
QFH antennas can be made 1/4 turn to 1 turn, 1/4 wave to 1 wave all with
different patterns. If done right they are a very effective antenna.

NOAA Tiros N satellites run 5 watts on 137 MHz. On 70 cm AO-51 is 1/2 W and
you lose 9 dB more for the increase in frequency. You have 3dB less galactic
noise on 70 cm, and another 3 dB for reduced bandwidth 37 KHz to 16 KHz.
Doing the math you are comparing 5 watts of (NOAA-18) to .250 effective
watts on AO-51 adjusted for noise power and frequency. A huge difference!

Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Luc Leblanc
Sent: Tuesday, June 09, 2009 8:43 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Another satellite-receiver option


I try also  to receive NOAA APT transmission with an helix but i got very
marginal results even with a preamp for 137khz. The signal was 
better but the pagers QRM was also boosted by about a factor of 5...

The only one viable solution was to use my VHF satellite beam with a PAR
electronics vhf notch filter part number 5602516. Of course you 
should have a 50khz band pass below that results are also very marginal. I
don't know if the PCR-100 is able to received at this bandwidth 
but the PCR-1000 can and it can be driven by WXtoimg software.


P.S. My home made helix is available for 35$ plus shipping but a bit hard to
securely fit inside a shipping box. pics available if needed.

On 8 Jun 2009 at 23:14, Jerry Clement wrote:

> I use a Hamtronics R139 Weather fax Receiver with a QFH antenna that I
built for receving and decoding images from the weather birds such as NOAA
18. I never had any luck with any of my other receivers such as my Icom R20,
being to narrow for this purpose,  although I know of guy's who have
modified receivers successfully for just this purpose. My set up may be seen
on my website: www.stormchaser.cjb.net  click on: Quadrifilar Helix Antenna.
The page needs to be upgraded, as I use a newer laptop than the one shown. 
> 
> Jerry VE6AB
> www.ve6ab.blogspot.com
> ___



"-"


Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE

 

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[amsat-bb] Re: Commercial Imports

[Art McBride]

To ALL,
As an Amateur Radio Operator I can modify any radio for Amateur Radio
operation, or build one from parts new or used. I can place in operation any
radio that I determine will not cause interference to other services and
will meet the requirements of FCC part 97.

If a radio is sold for commercial purposes and is type accepted anyone can
purchase it and if they are a licensed Amateur Radio Operator, operate it on
the Amateur bands. This is done on ships and aircraft every day and has
never been challenged to my knowledge. Commercial FCC licensed bands require
that type accepted equipment for that service must be used. 


Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Clint Bradford
Sent: Wednesday, June 10, 2009 9:33 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Commercial Imports

 >> ... Now on to using these radios.  Clint - since you have been  
stridently
insisting on the illegality of using non-FCC-certified radios on the US
ham bands, could you please show us the specific law/rule/regulation
that states that hams cannot use non-certified commercial gear in the
ham bands?

Some random - but pertinent - citations ...
47 U.S.C. § 302(b) of the Act provides that "[n]o person shall  
manufacture, import, sell, offer for sale, or ship devices or home  
electronic equipment and systems, or use devices, which fail to comply  
with regulations promulgated pursuant to this section."

Section 2.803(a)(1) of the Rules provides that "[e]xcept as provided  
elsewhere in this section, no person shall sell or lease, or offer for  
sale or lease (including advertising for sale or lease), or import,  
ship or distribute for the purpose of selling or leasing or offering  
for sale or lease, any radio frequency device unless in the case of a  
device subject to certification such device has been authorized by the  
Commission . . . ."

Radio transceivers operating in the 136 MHz - 174 MHz and the 400 MHz  
- 470 MHz bands are subject to the equipment certification process and  
must be certified and properly labeled prior to being marketed or sold  
in the United States.

47 U.S.C. § 503(b) of the Act provides that any person who willfully  
or repeatedly fails to comply substantially with the terms and  
conditions of any license, or willfully or repeatedly fails to comply  
with any of the provisions of the Act or of any rule, regulation or  
order issued by the Commission thereunder, shall be liable for a  
forfeiture penalty. The term "willful" as used in Section 503(b) has  
been interpreted to mean simply that the acts or omissions are  
committed knowingly. The term "repeated" means the commission or  
omission of such act more than once or for more than one day.
I will dig up my notes from a conversation with Bll Cross later n the  
week.

Clint, K6LCS



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[amsat-bb] Re: Gold plated contact

[Art McBride]

Luc,
 Standard solder is fine. During the soldering process the gold alloys with
the solder raising the reflow temperature. 
I would suggest rosin core solder, flux can be cleaned with alcohol.

Art, KC6UQH


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Luc Leblanc
Sent: Saturday, June 13, 2009 12:29 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Gold plated contact

Did any one has ever try to solder on gold metal contact pin? Is the
standard electronic solder is ok or?


"-"


Luc Leblanc VE2DWE
Skype VE2DWE
www.qsl.net/ve2dwe
WAC BASIC CW PHONE SATELLITE

 

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[amsat-bb] Field day and FO29

[Art McBride]

I need some help with the schedule for FO-29 The current listing schedule
begins with July 1, And I need the schedule for June 27th 18:00 UTC to June
28th 18:00 UTC.

 

Can anyone help me with this?

 Thanks, 

Art 

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[amsat-bb] Re: Field day and FO29

[Art McBride]

Thanks for all of the replies, I will be trying for it on FD.

 

Art, KC6UQH  

 

  _  

From: Jim Jerzycke [mailto:kq...@pacbell.net] 
Sent: Saturday, June 20, 2009 9:42 PM
To: kc6...@cox.net; AMSAT-BB; Andrew Glasbrenner
Subject: Re: [amsat-bb] Re: Field day and FO29

 


It appears to be in its "normal" mode as Drew said. I was just listening to
it about 2130 PDST, and there was quite a bit of activity. Unfortunately my
own uplink is clobbering my downlink and I didn't have any success in making
any contacts. I'm going to try the "duplexer trick" Sunday morning to see if
it helps with the desense problems I'm having.
Using two M2 eggbeaters with SSB USA preamps, and they're only about 8 feet
apart.
73, Jim  KQ6EA

--- On Sat, 6/20/09, Andrew Glasbrenner  wrote:


From: Andrew Glasbrenner 
Subject: [amsat-bb] Re: Field day and FO29
To: kc6...@cox.net, "AMSAT-BB" 
Date: Saturday, June 20, 2009, 8:31 PM

I believe FO-29 is operating continuously in Mode V/u analog at present.

73, Drew KO4MA

- Original Message - 
From: "Art McBride" 
To: "AMSAT-BB" 
Sent: Saturday, June 20, 2009 11:00 PM
Subject: [amsat-bb] Field day and FO29


>I need some help with the schedule for FO-29 The current listing schedule
> begins with July 1, And I need the schedule for June 27th 18:00 UTC to 
> June
> 28th 18:00 UTC.
>
>
>
> Can anyone help me with this?
>
> Thanks,
>
> Art
>
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[amsat-bb] Re: dream your own sat

[Art McBride]

Rupert,
I think that is a fair assumption on your part, but only because the are no
new ideas being presented that have commercial potential that can use
Amateur Radio as an inexpensive to proof of concept. 
In the present Amateur Radio community only Emergency Communications is
getting the publicity. Perhaps FEMA or the Red Cross might help pay for an
emergency communication satellite otherwise it is LEO's forever!

Art, KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of rupert red
Sent: Sunday, July 05, 2009 4:47 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] dream your own sat


Hallo all...

from a while I'm hearing about MANY different and interesting satellite
solutions...

LEO, MEO, HEO, GEO... MOON !!!

The problem is only ONE !

Amateur radio community has no money for this project, and will never have!

Amsat & Co will never be able to collect millions I red on this bb that
hams has no money for an expensive ground station... then how can they send
many money to Amsat?

Public and private organizations all over the world have not an high
consideration of hams, and will never invest founds for them.

The conclusion is only ONE... we will never see a new oscar satellite in the
sky (at least some student's cube).

Let's all dream together guys.

 

Best 73 Rupert

_
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[amsat-bb] Re: I just curious

[Art McBride]

LeRoy,
 This has been done with the RS birds (2M/10M). 
6M and 1 1/4M are not allowed in all Regions (1-3) which leaves only 10M and
2M for an all VHF Satellite. The major draw back to this mode is during peak
Sunspot activity, signals from the Satellite can not get through the
Ionosphere on 10M.
Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of kd8...@aol.com
Sent: Sunday, July 05, 2009 12:07 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] I just curious

This is probably one of those questions that has a very simple answer maybe
something I wasn't thinking of. 

On the FM birds how come the split is V/U or U/V?  Are there any V/V birds? 

I mean if doppler doesn't effect the vhf as much wouldn't it make since to
have some V/V?  Wouldn't have to worry about doppler anyways

I know there is a reason, so I am curious that is all!

LeRoy, KD8BXP
http://www.HamOhio.com

Sent on the Now Network from my SprintR BlackBerry




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[amsat-bb] Re: 3/16" stainless retainers

[Art McBride]

Try McMaster Carr
http://www.mcmaster.com/#

This is a great place to buy small quantities, credit card orders ship the
next day.

Art, KC6UQH


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Jim Jerzycke
Sent: Wednesday, July 08, 2009 8:36 PM
To: Amsat-BB; R. Chastain
Subject: [amsat-bb] Re: 3/16" stainless retainers

I've found a bunch of places that *make* them in stainless, but they all
have rather large minimum buys.
If there's enough interest, I'll consider buying them, and selling them to
other AMSAT members for whatever price they cost me.
Jim  KQ6EA

--- On Wed, 7/8/09, R. Chastain  wrote:

From: R. Chastain 
Subject: [amsat-bb]  3/16" stainless retainers
To: "Amsat-BB" 
Date: Wednesday, July 8, 2009, 4:36 PM


Anyone know where the least expensive place is to purchase 3/16" stainless
steel retainer washers?

Thanks,
RoD
KD0XX


      

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[amsat-bb] Re: New ICOM VHF / UHF / SHF Radio

[Art McBride]

ICOM trash software for the D800H is terrible, and the OPC-UP478C serial to
USB adapter that they sell as an accessory will not work on Vista. The FTDI
chips are the best solution, but ICOM doesn't make money selling an FTDI
solution. 
After an IC-820 and the D800 I am looking for another brand of radio. 
Will their new radio USB run on Vista? 
Art
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of w8iss
Sent: Sunday, August 23, 2009 5:09 PM
To: Bruce Robertson
Cc: AMSAT-BB
Subject: [amsat-bb] Re: New ICOM VHF / UHF / SHF Radio

On Sun, 2009-08-23 at 20:56 -0300, Bruce Robertson wrote:
Finally, it appears this rig has a USB port. It really would make
> sense for manufacturers today to use the FTDI serial chip and avoid
> all the silliness with serial/usb converters not working properly with
> their protocols.
> 
> 73, Bruce
> VE9QRP

Why not just go ethernet and assign an MAC address to it and be done
with it or is ethernet another one of those protocols that have gone
the route of the serial port?

James W8ISS

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[amsat-bb] Re: Don't Fly SuitSat2 to ISS (rebuttal)

[Art McBride]

Either we make history, or we complain about it. The choice is ours! 
This thread is dead!

Art KC6UQH  

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of John P. Toscano
Sent: Monday, August 24, 2009 9:57 PM
To: Amsat BB
Subject: [amsat-bb] Re: Don't Fly SuitSat2 to ISS (rebuttal)

Rocky Jones wrote:

> As for AO-40.  It failed for the same reason that suitsat 1 did, and for
the same reason that a lot of people who build their own airplane kill
themselves every year trying to "test fly it"the project got to big for
the organization that was building it...ie their technical competence was
insufficient for the task at hand.
> 
> But in your view (at least as best as I understand it) that evaluation
should not be made because "at least they tried".
> 
> sorry I dont buy that logic
> 
> Robert WB5MZO

I'm not quite sure who is quoting whom, i.e. if the quote above is by 
Rocky, who sent the email, or Dan, who is mentioned above the quotation 
that I excerpted, or by Robert, who seems to have signed it.

In any case, irrespective of who wrote it, the gist of it is getting 
under my skin...

"As for AO-40. It failed..." (because) "...the project got to (sic) big 
for the organization that was building it...ie (sic) their technical 
competence was insufficient for the task at hand"

Spelling and grammar aside (or maybe small details REALLY ARE important? 
-- just a random thought), it is hard to disagree logically with the 
fundamental principle. In less inflammatory terms, a bunch of amateurs 
who were not really rocket scientists tried to build a satellite, and 
they weren't able to pull it off 100% successfully because they tried to 
do more than they were qualified to do.

Nevertheless, does this mean that we should:
   a) never try to do something harder than what we KNOW in advance that
  we are capable of accomplishing?

   b) never make mistakes, even though the only way to guarantee that
  you will never do anything WRONG is by DOING NOTHING AT ALL?

   c) LEARN from our mistakes and try again?

Personally, I vote for number 3. Note that choice #3 doesn't say "keep 
repeating our mistakes", it says "LEARN from them" and implies that when 
we try again, we do so in a manner wherein we are better prepared than 
we were the time before.

OK. I am mad as hell that someone failed to notice the bright red (or 
was it yellow) flag attached to a port cap that clearly said "REMOVE 
BEFORE FLIGHT", and caused the AO-40 propulsion system to self-destruct 
when activated. But dang it all, people should stop carping about the 
number, complexity, and even frequencies of the transponders that were 
placed aboard AO-40, because NONE of that had ANYTHING to do with the 
reason it failed. In fact, as I've said before, and has fallen on deaf 
ears before (or maybe it's on blind eyes), the COMPLEXITY of AO-40 is 
what SAVED it at all, made it usable at all, for the short time we had 
her around to enjoy. One transponder is blown up, switch over to a 
different one. Etc.

Call the AMSAT builders "incompetent" as many times as you want, it does 
not change one ugly fact. If you want a high earth orbit satellite (and 
I most certainly DO), IT MUST BE A COMPLEX DEVICE. ROCKET PROPULSION 
SYSTEMS ARE COMPLEX, BEST UNDERSTOOD BY ROCKET SCIENTISTS, AND YOU WILL 
NEVER GET TO H.E.O. WITHOUT ONE.

So, either stop whining that you want an H.E.O. satellite, or stop 
whining about wanting a satellite that is not complex. We either get the 
training/education/experience that allows us to "get it right", or we 
abandon the task and take up knitting. Or we keep stumbling around in 
the dark making lots of expensive mistakes. But as Scottie told Captain 
Kirk, "I'm sorry captain! I canna change the laws of physics!" A 
satellite in high earth orbit is a complex device.

And talk about having their heads inserted into their anal orifices, we 
have people saying, in essence, "you people are too stupid to make a 
complex high-earth-orbit satellite work", and at the same time, "you 
people are foolish to invest any energy into educating students about 
satellite technology", or even worse, "you are foolish to try to take 
students who are already interested in satellite technology and get them 
excited about the possibility of using that technology for 
non-commercial (i.e., AMATEUR) radio communications". Give me a break. 
Maybe one of those folks, a REAL rocket scientist, will someday be the 
person who leads us amateurs to success.

It all boils down to this. There is a nearly infinite number of 
non-productive choices that do not further the cause of progress. There 
are three fundamental choices that DO lead to progress:
   1) LEAD
   2) FOLLOW
   3) GET THE HELL OUT OF THE WAY AND LET SOMEONE ELSE DO IT

73 de WØJT
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[amsat-bb] SatPC32

[Art McBride]

Hi All,

 I am trying to get my ICom 820H working under CAT. 

I have an OPC-478UC It is USB to single line CI-V required by the ICom 820H.
I have shifted it's output to the tip from the sleeve on the 1/8" phone
plug. Under System / Device hardware the OPC 478 shows up as com 3.  The
radio does not control.  I have set the address to 60h from 42h in the radio
and the baud rate to 9600 on both radio and program. I get the E/A Fehler-32
warning when I try to store the com port values. The OPC 478UC does work my
ICom D800 and when connected to the 820H will return a Com 3 when com port
is selected. If I unplug the cord to the 820H it tells me no radio is
connected.   

 

Any help on this one would be appreciated. 

 

Art, 

KC6UQH 

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[amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE

[Art McBride]

To All,
The Diplexer also acts as a filter. All solid state transmitters have "White
Noise" contributions. If you receive while transmitting the White Noise from
the 2M side will desense the 70 cm receiver. The amount of noise typically
60 dB down from the carrier varies with the type of output filter used in
the transmitter.  Of course this does not apply when working the satellite
simplex. 
A bad diplexer can also be the problem. Soldering is poor in some of these
overseas units, also excessive power in a former life will cook the parts
inside. A good test with 50 loads and a power meter will tell the condition
of the diplexer.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Joe
Sent: Friday, September 25, 2009 6:43 PM
To: Gary "Joe" Mayfield
Cc: 'AMSAT-BB'
Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE

as in the texts below,  there is something else going on here.

That Diplexor can not be all that bad. two reasons.

How many db down is the front to side of that antenna?

and I can not imaging someone would sell a diplexor that has greater 
than 20 db of losses.

because of the statement that how criticalpolarity was with the 
original, and now the antenna has to be nearly 90 degrees cross 
polarized to make it drop out  uhh

that close to 30 db,

at least 20,,

something else is going on here

Gary "Joe" Mayfield wrote:

>>
>>Another issue I came across was how wide the beamwidth is of the Arrow
>>Antenna between the Arrow diplexer and the new diplexer.  I was wondering
>>
>>
>if
>  
>
>>this was going to happen and it did.  The reason that this happened was
>>
>>
>with
>  
>
>>the old diplexer, the signal attenuated so much that you had to be pointed
>>right smack dab on the bird, a few degrees off and you lost the signal.
>>Now, with the new diplexer, you can point the beam in the general
>>
>>
>direction
>  
>
>>and still copy the bird.  In most cases I had to turn the beam 90 degrees
>>before I completely lost the downlink!  Twisting the antenna to make
>>polarization changes makes absolutely no difference now.  This also
>>attributes to the fact that now I'm copying the entire pass without
>>
>>
>dropouts
>  
>
>>or fades.  Makes sense.  What I've regained over the lossy diplexer makes
>>
>>
>up
>  
>
>>for any polarization differences, etc. for a better copiable signal.
>>
>>Next weekend I will have to try more passes and get a feel of how much
>>
>>
>this
>  
>
>>system has changed.
>>
>>
>>73,
>>
>>Jeff  WB3JFS
>>Las Vegas, NV
>>DM26
>>
>>
>>
>>
>>
>>
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>>
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[amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs

[Art McBride]

The most comprehensive info on QFH antennas is the Microwave Journal
December 1970 Pgs 49-54 By CC Kilgus.

Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of i8cvs
Sent: Wednesday, September 30, 2009 5:35 AM
To: AMSAT-BB; Franklyn A. Ballentine, jr
Subject: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs

Hi Frank, KB1QZH

The best starting point is the original article of the inventor of QHA i.e
Walter Maxell, W2DU

In a separate email I have attached the above fundamental article.

73" de

i8CVS Domenico

- Original Message -
From: "Franklyn A. Ballentine, jr" 
To: "i8cvs" 
Cc: "AMSAT-BB" 
Sent: Tuesday, September 29, 2009 6:45 PM
Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design
specs


I have a question along the same line.  Is the QHA in the ARRL
Satellite Handbook \ Antenna handbook, a good starting place?

Thanks,
Frank B.
KB1QZH

On Tue, Sep 29, 2009 at 11:17 AM, i8cvs  wrote:
> - Original Message -
> From: "Tim Goodrich" 
> To: 
> Sent: Monday, September 28, 2009 9:45 PM
> Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
>
>> Hi All,
>>
>> The house I just bought precludes me from even using my arrow inside as
>> there must be something un-RF friendly in the walls. Therefore, I was
>> looking for a roof antenna and the October QST article on the QFH
inspired
>> me to build one. However, after doing some research, I have come up with
> two
>> sets of design specs and I'm unsure which one is correct.
>>
>>
>>
>> I converted everything from you're the 146Mhz QST model to 436Mhz.
> However,
>> when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
>>
>> The values it puts out are different in the "compensated length" field.
> The
>> only difference is this model calculates for a full turn as opposed to a
>> half turn, but the lengths shouldn't be as different as it says. Under
the
>> QST model, I get a wavelength of 688mm, but under the website's model, it
>> gives me a "compensated wavelength" of 729mm.
>>
>>
>>
>> The values I used to calculate are:
>>
>> 436
>>
>> 1
>>
>> 1
>>
>> 15
>>
>> 2
>>
>> .23
>>
>>
>>
>> Can anyone tell me which specs to use and/or explain this compensated
>> wavelength issue?
>>
>>
>>
>> Thank you,
>>
>> Tim
>>
>> KI6VBY
>>
> Hi Tim, KI6VBY
>
> Read please the book "REFLECTION" Transmission Lines and Antennas by
> M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages
> 22-1 to 22-23 and also
> "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
The
> AMSAT Journal May/June 2004
> In a separate email I have sent to you both articles as an attachement.
>
> 73" de
>
> i8CVS Domenico
>
>
>
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[amsat-bb] Re: antenna question

[Art McBride]

Samudra,
You could use a polar mount and preset mast angle and azmuth before each
pass. That will give you a single axis control. Most antennas are moer that
30 degrees in beamwidth, the system only needs to be close +/- 15 degrees to
have max signal.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Samudra Haque
Sent: Thursday, October 22, 2009 12:16 PM
To: Amsat-bb
Subject: [amsat-bb] Re: antenna question

While searching for public text concerning Amateur satellites and
phased array antennas, I came across this gem from our very own Tom
Clark, K3IO
http://mysite.verizon.net/w3iwi/electronic_scanning_antennas.pdf,
"Electronic Scanning Antennas for Amateur Spacecraft". I wonder if
this knowhow could be utilized for ground stations to have antennas
that could rapidly switch between different birds by a software reload
function and a intelligent switching matrix ?

How many of you would prefer (if a command station) to have
multi-access to satellites as they pass during conjunction but use a
small antenna farm selectively to access them _simultaneously_.

On Thu, Oct 22, 2009 at 3:06 PM, Samudra Haque 
wrote:
> Hi, Amsat-BB
>
> Are there any antenna designs that use predominantly rotating
> sub-reflectors and a reflector for tracking LEO birds, in contrast to
> rotating the main antenna structure on booms in the AZ-EL directions ?
> I am aware of multi-LNB antenna arrangements, thought it would be
> interesting to find out ways to keep a fairly large reflector constant
> on the ground and use a smaller steerable sub-reflector or horn feed
> to aim the beam ?
>
> Any ideas ?
>
> Samudra N3RDX
>
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[amsat-bb] Re: AO-51 - After the Change

[Art McBride]

Clint,
Rotating a linear polarized Yagi in a circularly polarized field should
result in less than a few dB of change, no change if the circular antenna is
perfectly circularly polarized. When using a linear antenna ground effects
including reflections will cause a larger change. Using circular on both
ends will result in less fading from the ground effects and no change in
signal for antenna rotation on the S/C side providing the S/C antenna has a
good pointing angle. Losses of 22 +dB are reserved for cross polarization of
antennas H-V and LH to RH.

Art, KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Clint Bradford
Sent: Sunday, December 06, 2009 7:15 PM
To: Glenn AA5PK
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: AO-51 - After the Change

 >> ... I think the handheld ops have less trouble with the polarity  
switching because tend to compensate more quickly with a twist of the  
wrist ...

That phenomenon is not evident now - nor has it ever been - for me on  
AO-51.

I know the engineers say I am supposed to be increasing or decreasing  
my signal strength by 22 or 23db by merely twisting my Yagi 90  
degrees. But I have hundreds of witnesses during dozens of  
demonstrations who will tell you that when the Yagi is turned 90  
degrees, there's no discernible change in the signal.

This is not a scientific approach to the subject, of course. Just what  
my aging ears can hear.

I have heard fellow AMSAT members describe AO-51's "signal fading due  
to the satellite tumbling in space," too. I am not using elaborate  
equipment, but have no idea what they are talking about.

Just my firsthand observations. Guess I could be wrong ... we are a  
little different - I am told - out hre on the West Coast of the US.

Clint Bradford, K6LCS




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[amsat-bb] Re: UHF QRM from HAM stations!!

[Art McBride]

In the USA, US Military has priority over all users on the 420-450 MHz band.
Amateur Operators are secondary (cannot cause harmful interference to US
Military. 
Under the terms of Part 15 all users under Part 15 must accept harmful
interferences and must no cause harmful interference to other users.

BTW: ISM refers to services that do not intentionally radiate and do not use
radiation for communication purposes. A Microwave is ISM. A WiFi is not. 
Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Glen Zook
Sent: Sunday, December 20, 2009 9:20 AM
To: amsat-bb@amsat.org; Luc Leblanc
Cc: eu-am...@yahoogroups.com
Subject: [amsat-bb] Re: UHF QRM from HAM stations!!

I don't think so!

As secondary users, at least in the United States, we even have to "put up"
with all the 47 CFR Part 15 devices on 433 MHz.

Glen, K9STH

Website:  http://k9sth.com


--- On Sat, 12/19/09, Luc Leblanc  wrote:

On UHF the band is shared up to a point the "other side" is considering us
as "interference" at least in 2005... Just check slide 9 in the power point
below. Can we also found them as QRM i think not as we are on a secondary
basis :(

www.dtic.mil/ndia/2005rangeops/tuesday/owens.pps



  
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[amsat-bb] Re: AO40 contacts and P3-E

[Art McBride]

To All,
 It takes more than 1000 LEO's to equal an HEO. I really enjoyed AO40 and
All I had was a speaker tripod for my 13 cm dish and a 6' stepladder to
support my 10 T helix.
Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of i8cvs
Sent: Sunday, February 06, 2011 12:10 PM
To: Peter Guelzow; Amsat - BBs
Subject: [amsat-bb] Re: AO40 contacts and P3-E

- Original Message -
From: "Peter Guelzow" 
To: 
Sent: Friday, February 04, 2011 5:17 PM
Subject: [amsat-bb] AO40 contacts and P3-E

Hi All,

> You guys are making me all teary-eyed!  I loved that bird, especially for
all the "challenges" it presented.

Ughh..  this really hit's me hard and I'm getting very sentimental
reading all email's to this topic.
But it gives me also

The launch campaign in french Guiana, were I was staying in Kourou for
more than quarter of the year, and the re-birth of AO-40 on Christmas
were the most exciting days in my life.

I haven't made many contacts, I was more among the "listeners" and
enjoyed the fun.

It's sometimes very frustrating to me that 10 years after the launch of
AO-40 we still haven't got P3-E into orbit.
We have been going to many up's and down's during this time, but we are
not giving up.
There are new challenges we are working on presently and some of them
give us a good hope of success.
Indeed and I'm sorry for that, It has been very quiet about the progress
of P3-E in the last year.
While most mechanical work is done, there was also progress on the
electronics, mostly the IHU.
However, one of the biggest challenges is indeed funding and a launch we
can afford.
That's where we a concentrating most of our efforts and time at the moment

Indeed, we need the support of the community. There will only a P3-E, if
we all really want it..

If you want to support P3-E, than please visit
http://www.p3e-satellite.org/?lang=en_EN and make a direct donation to
the project - THANKS!

73s Peter, DB2OS

Peter Gülzow
President AMSAT-DL

Hi Peter, DB2OS

In my opinion AO40 was the best satellite ever made by AMSAT-DL and it
was very fun until lasted.

We all hope that AMSAT-DL will find a launch opportunity with ESA and
a ARIANE-5 launcher with P3-E inside the SPELDA adapter as soon as
possible.

Pulling for P3-E ! !

73" de

i8CVS Domenico

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[amsat-bb] Re: Antenna Analyzer

[Art McBride]

Domenico,

For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have
never expected MFJ products to be in the League of Anristu, HP and Rohde and
Swartz. 
MFJ is a yard stick, the others are a micrometers
Art,
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of i8cvs
Sent: Sunday, March 06, 2011 9:41 AM
To: Pete Rowe; AMSAT BB; Howard Kowall
Subject: [amsat-bb] Re: Antenna Analyzer

Hi Pete, WA6WOA

I do not recommend the MFJ-269 antenna analyser because it is very
inaccurate particularly on 435 MHz
I have compared the MFJ-269 with several professional network analysers and
I have found that at most the MFJ is usable up to 30 MHz maximum because
above 30 MHz the inaccuracy on the real part and the imaginary part of the
impedance reading becomes absolutely unacceptable.

My MFJ-269 was purchased as new but connecting to it a professional
50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz
was 1.1

I have sent back my MFJ to the factory for inspecting  and calibration but I
belive that the above instrument was a very bad affair for me and will be a
bad affair for all that intend to use the analyser above 30 MHz.

Be happy with your MFJ-269 even if  dreaming while sleeping I am sure that
my message made you suspect a wrong real part and a wrong imaginary part
on your impedance reading !

Best 73" de

i8CVS Domenico

- Original Message -
From: "Pete Rowe" 
To: "AMSAT BB" ; "Howard Kowall" 
Sent: Sunday, March 06, 2011 4:45 PM
Subject: [amsat-bb] Re: Antenna Analyzer


Hi Howard
I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy
size. Highly recommended. (no, I don't own stock in MFJ)
One word of caution: mine (and maybe there is something wrong with mine)
draws some power from the batteries with the power switch OFF. So I take one
of the batteries out when not in use.

73,
Pete
WA6WOA

--- On Sun, 3/6/11, Howard Kowall  wrote:

From: Howard Kowall 
Subject: [amsat-bb]  Antenna Analyzer
To: "AMSAT BB" 
Date: Sunday, March 6, 2011, 6:16 AM

Hello to everyone
I am seriously thinking about buying an antenna analyzer,I build enough
antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all
flavors.The standard swr bridge is just not cutting it anymore.So I guess
what I am looking for is one that will do 3mhz to 500mhz,nice to have
computer interface but not a priority.I have seen a few on the internet but
its nice to get some user input,rather then the sales pitches.
Thanks to all who read and reply in advance
Howard
VE4ISP
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[amsat-bb] Re: Antenna Analyzer

[Art McBride]

Domenico,

A. It is much smaller than MY H/P 8410 + 8414 + test set, & sweep generator.
B. It will tell me if the resistive arm is above or below 50 Ohms. 
C. It will give me the reactance Vs frequency with in 10 ohms.
D. It is battery operated, portable, and can be used on a tower.
E. It costs less than a 1 month rental of a quality Network Analyzer.
F. A VSWR measurement will not separate the resistive and reactive arms 
G. When tuning an antenna you never start at 1.5 :1!If it is that good there
is no need to tune it.

73,
Art,
KC6UQH
 
-Original Message-
From: i8cvs [mailto:domenico.i8...@tin.it] 
Sent: Sunday, March 06, 2011 12:30 PM
To: kc6...@cox.net; 'Pete Rowe'; 'AMSAT BB'; 'Howard Kowall'
Subject: Re: [amsat-bb] Re: Antenna Analyzer

Hi Art, KC6UQH

If you are satisfied with an antenna  VSWR in the order of 1.5 : 1 then
you don't need an antenna analyser but only a VSWR meter.

An antenna analyser must be able to measure with accuracy the real part and
the imaginary part of the impedance i.e. the resistive and the reactive part
of the impedance Z = R +/- jX

For example the same antenna VSWR of 1.5 : 1 can be obtained with an
antenna impedance having the following values and all of them are laying
over the same VSWR circle of the Smith Chart

Z1 = 38+j13 ohm
Z2 = 66+j16 ohm
Z3 = 58- j20 ohm
Z4 = 34- j0   ohm

Since the same VSWR can be found over a VSWR circle then the values
of the impedance giving the same VSWR are infinite values.

The MFJ-269 analyser make acceptable  R +/-jX measurements only up to
30 MHz but fail to measure accurate resistive and reactive part of the
impedance above 30 MHz and in other words it is not a respectable antenna
analyser.

Why to wast money to buy an antenna analyser to measure wrong values of
Z= R+/- jX if been happy with only the value of the VSWR you need only a
VSWR meter ?

73" de

i8CVS Domenico

----- Original Message -
From: "Art McBride" 
To: "'i8cvs'" ; "'Pete Rowe'" ;
"'AMSAT BB'" ; "'Howard Kowall'" 
Sent: Sunday, March 06, 2011 7:38 PM
Subject: RE: [amsat-bb] Re: Antenna Analyzer


> Domenico,
>
> For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have
> never expected MFJ products to be in the League of Anristu, HP and Rohde
and
> Swartz.
> MFJ is a yard stick, the others are a micrometers
> Art,
> KC6UQH
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of i8cvs
> Sent: Sunday, March 06, 2011 9:41 AM
> To: Pete Rowe; AMSAT BB; Howard Kowall
> Subject: [amsat-bb] Re: Antenna Analyzer
>
> Hi Pete, WA6WOA
>
> I do not recommend the MFJ-269 antenna analyser because it is very
> inaccurate particularly on 435 MHz
> I have compared the MFJ-269 with several professional network analysers
and
> I have found that at most the MFJ is usable up to 30 MHz maximum because
> above 30 MHz the inaccuracy on the real part and the imaginary part of the
> impedance reading becomes absolutely unacceptable.
>
> My MFJ-269 was purchased as new but connecting to it a professional
> 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz
> was 1.1
>
> I have sent back my MFJ to the factory for inspecting  and calibration but
I
> belive that the above instrument was a very bad affair for me and will be
a
> bad affair for all that intend to use the analyser above 30 MHz.
>
> Be happy with your MFJ-269 even if  dreaming while sleeping I am sure that
> my message made you suspect a wrong real part and a wrong imaginary part
> on your impedance reading !
>
> Best 73" de
>
> i8CVS Domenico
>
> - Original Message -
> From: "Pete Rowe" 
> To: "AMSAT BB" ; "Howard Kowall" 
> Sent: Sunday, March 06, 2011 4:45 PM
> Subject: [amsat-bb] Re: Antenna Analyzer
>
>
> Hi Howard
> I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy
> size. Highly recommended. (no, I don't own stock in MFJ)
> One word of caution: mine (and maybe there is something wrong with mine)
> draws some power from the batteries with the power switch OFF. So I take
one
> of the batteries out when not in use.
>
> 73,
> Pete
> WA6WOA
>
> --- On Sun, 3/6/11, Howard Kowall  wrote:
>
> From: Howard Kowall 
> Subject: [amsat-bb]  Antenna Analyzer
> To: "AMSAT BB" 
> Date: Sunday, March 6, 2011, 6:16 AM
>
> Hello to everyone
> I am seriously thinking about buying an antenna analyzer,I build enough
> antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all
> flavors.The standard swr bridge is just not cutting it anymore.So I guess

> what I am looking for is one that will do 3mhz to 50

[amsat-bb] Re: AO-40 range record ??

[Art McBride]

P.H.,

Certainly no distance records but from DM13 I have worked from the U.K. to
the east, all across the Americas, and as far as Japan to the West. Passes
were in view for 12+ hours here. All contacts were made using homebrew
equipment and portable antennas in my back yard.
Despite technical problems, it was the best satellite ever.

Art,
KC6UQH

 
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of P.H.
Sent: Saturday, March 19, 2011 6:18 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] AO-40 range record ??

Hi,

For a small club satellite presentation I will be mentioning the
benefits of HEO over LEO and the range advantage.

Can anyone tell me the distance record set when AO-40 was alive?

Thanks

73

2i0VAX

Pete
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[amsat-bb] Re: Diplexer

[Art McBride]

As I understand it,
A Duplexer allows for transmission and reception to take place in the same
band using a single band antenna. 
A Diplexer allows for transmission and reception to take place on different
bands using a multi-band antenna.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of i8cvs
Sent: Saturday, April 09, 2011 10:35 AM
To: Amsat - BBs; Anthony Monteiro
Subject: [amsat-bb] Re: Diplexer

- Original Message - 
From: "Anthony Monteiro" 
To: 
Sent: Saturday, April 09, 2011 5:15 PM
Subject: [amsat-bb] Re: Diplexer

> A "duplexor" is a device that allows both transmitting and
> receiving over the same transmission line or antenna. It
> may or may not be a passive device and it may or may not
> be frequency selective.
> 
> In WWII RADAR systems, a duplexor was used to allow
> the transmitter and receiver on the same frequency to
> share the same antenna. The duplexor was a waveguide
> device that had special gas-filled tubes to quickly
> switch the signal direction.
> 
> 73,
> Tony AA2TX
> 
Hi Tony, AA2TX

I have in my hands the Instruction Book for Radar Recognition 
Sets AN/UPX-6  of U.S. Navy  Department Bureau of Ships.

The UPX6 is a IFF transponder on board of aicrafts and was used
in WWII for  Identification of Friend or Foe.

The UPX-6  can transmit from 1010-1030 MHz and receive from
1090-1110 MHz and allows both transmitting and receiving over
the same transmission line and antenna via a circuit  made of coax
cable RG-58/CU that the manual calls a   "DUPLEXER" and not
a "duplexor".

This "duplexer" is working on the fact that a transmission line,
shorted at the far end a quarter wavelenght long for the incoming
signal,represent infinite impedance (an open circuit) at the sending
end of the line.

The UPX-6 was converted in the early 1980's to be used on 1296 MHz
and an interesting article written by W6NBI was published in Ham
Radio Magazine march 1981

I modified it and I got 40 watt output...not too bad for that epoch
time ! 

Best 73" de

i8CVS Domenico
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[amsat-bb] Re: Diplexer

[Art McBride]

Andrew,
Both Duplexer and Diplexer allow for transmit and receive at the same time.

A duplexer, as used on a 2 meter repeater has an extremely narrow filter
allowing transmit on IE: 146.000 MHz and receive on 146.600 MHz. They
typically use cavity resonators, each cavity is 30" tall and 7-10" in
diameter and it takes 6 of them to make it work well. They must be tuned to
the repeater transmit and receive frequencies. 

A Diplexer is a small box with two filters allowing you to transmit on two
bands, receive on two bands, or transmit on one band and receive on the
other band at the same time. The diplexer keeps the bands separate to
prevent damage to the equipment on the other band.

Also there exists a Triplexer which is the same as a Diplexer but it
supports three bands. I have one here for 2M, 70cm, and 23cm. I use it on a
triband base antenna with a Kenwood TM 741A 

A Diplexer or Triplexer can be used to connect antenna connectors of radios
on different bands to a common coax, three antennas to a common coax or both
to use one run of coax for two or more bands. 

The Circulator mentioned for the radar is different from the Duplexer and
diplexer in that it allows the receiver and transmitter to be connected to
the antenna while the transmitter is operating. There are T/R and anti T/R
switches to prevent damage to the radar receiver during transmit and reflect
receive signals that reach the transmitter to the receiver. This is a pulse
echo system so receiver and Transmitter never function at the same time but
require a fast antenna switching time. A typical marine radar, switches from
Transmit to receive in 150 nS resulting in ~300 yards of "blindness"
measured from the antenna to the first target the radar can see. 


I hope this clarifies the differences.
Art,
KC6UQH

 
-Original Message-
From: Andrew Rich [mailto:vk4...@tech-software.net] 
Sent: Saturday, April 09, 2011 1:39 PM
To: kc6...@cox.net; 'i8cvs'; 'Amsat - BBs'; 'Anthony Monteiro'
Subject: Re: [amsat-bb] Re: Diplexer

DU = TX RX
DI = RX
- Original Message - 
From: "Art McBride" 
To: "'i8cvs'" ; "'Amsat - BBs'" ;

"'Anthony Monteiro'" 
Sent: Sunday, April 10, 2011 6:27 AM
Subject: [amsat-bb] Re: Diplexer


> As I understand it,
> A Duplexer allows for transmission and reception to take place in the same
> band using a single band antenna.
> A Diplexer allows for transmission and reception to take place on 
> different
> bands using a multi-band antenna.
>
> Art,
> KC6UQH
>
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of i8cvs
> Sent: Saturday, April 09, 2011 10:35 AM
> To: Amsat - BBs; Anthony Monteiro
> Subject: [amsat-bb] Re: Diplexer
>
> - Original Message - 
> From: "Anthony Monteiro" 
> To: 
> Sent: Saturday, April 09, 2011 5:15 PM
> Subject: [amsat-bb] Re: Diplexer
>
>> A "duplexor" is a device that allows both transmitting and
>> receiving over the same transmission line or antenna. It
>> may or may not be a passive device and it may or may not
>> be frequency selective.
>>
>> In WWII RADAR systems, a duplexor was used to allow
>> the transmitter and receiver on the same frequency to
>> share the same antenna. The duplexor was a waveguide
>> device that had special gas-filled tubes to quickly
>> switch the signal direction.
>>
>> 73,
>> Tony AA2TX
>>
> Hi Tony, AA2TX
>
> I have in my hands the Instruction Book for Radar Recognition
> Sets AN/UPX-6  of U.S. Navy  Department Bureau of Ships.
>
> The UPX6 is a IFF transponder on board of aicrafts and was used
> in WWII for  Identification of Friend or Foe.
>
> The UPX-6  can transmit from 1010-1030 MHz and receive from
> 1090-1110 MHz and allows both transmitting and receiving over
> the same transmission line and antenna via a circuit  made of coax
> cable RG-58/CU that the manual calls a   "DUPLEXER" and not
> a "duplexor".
>
> This "duplexer" is working on the fact that a transmission line,
> shorted at the far end a quarter wavelenght long for the incoming
> signal,represent infinite impedance (an open circuit) at the sending
> end of the line.
>
> The UPX-6 was converted in the early 1980's to be used on 1296 MHz
> and an interesting article written by W6NBI was published in Ham
> Radio Magazine march 1981
>
> I modified it and I got 40 watt output...not too bad for that epoch
> time !
>
> Best 73" de
>
> i8CVS Domenico
> ___
> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA me

[amsat-bb] Re: The Need for Phonetics

[Art McBride]

Glen,
Engineers use KW for kilowatt. That might explain my confusion using KW
abbreviation as an occupation for 30 years before becoming an Amateur Radio
Operator.
Art,
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Glen Zook
Sent: Sunday, April 10, 2011 9:33 AM
To: amsat-bb@amsat.org; Mark Spencer
Subject: [amsat-bb] Re: The Need for Phonetics

Although some people say kilowatt is two words, it definitely is not.  In
over 50 years of using "kilowatt" as a phonetic I have not once had a
station think it is KW.  Kilowatt makes it through QRM and QSB a LOT better
than "kilo".  Some operators do use "Kansas" or "Korea" for the letter "K".

Glen, K9STH

Website:  http://k9sth.com


--- On Sun, 4/10/11, Mark Spencer  wrote:

The use of Kilowatt as a phonetic is a pet peeve of mine especially where
there is a brief pause between kilo and watt.   When I hear kilo I assume
the letter k is being represented, then when I hear watt I have to decide if
the sender is also representing the letter w or not.
 
It seems overly confusing to me.

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[amsat-bb] Re: ground plane on

[Art McBride]

J-Pole antennas are a 1/2 wave element with a 1/4 wavelength matching stub.
The Matching stub allows the dipole to be fed from the bottom end without
interference from the feed line. Open Line (J), tapped coax, or LC Circuit
can be used to match the dipole to a coax at the end, accomplishing the same
performance, including the same overhead null one expects from a vertical
dipole.

Art, 
KC6UQH  

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Andrew Rich
Sent: Saturday, April 16, 2011 11:03 PM
To: KF1BUZ
Cc: 
Subject: [amsat-bb] Re: ground plane on

http://www.youtube.com/watch?v=L4v9wKMxRHQ&feature=youtube_gdata_player

Sent from my iPhone
Andrew Rich

On 17/04/2011, at 15:53, KF1BUZ  wrote:

> A Copper Jpole, has this been tried?
> Just thinking it might make my getting into the birds better.
> 
> Thanks
> Dan
> KF1BUZ
> 
> 
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[amsat-bb] Re: Icom D-Star

[Art McBride]

Tony,
How it happened in the HDTV world is the transmitting stations pay huge
royalties for the IP. You do not see any CH3 adapters for HDTV. Separate
royalties are required for video and sound and no provisions, for Amateur
Radio experimentation using HDTV has been made. 

Amateur Radio is a DIY, learn by doing hobby that also provide services to
the public. We have no revenue stream to pay for equipment royalties.

D-Star Codec royalties are with in reach ($22.00 for a codec) and it is an
open protocol. It has multipath and synchronization problems. Amateurs are
currently experimenting with D-Star HB modem/controllers and radio
equipment. As with D-Star home brewing will need to transition from
individual to group efforts for new projects.

Satellites will play an increasing role in digital communications as
multipath can be dealt with effectively using circular polarization and
directive antennas. Most digital systems are not very multipath friendly. 

Amateur Radio weak Signal work and contesting most likely will remain with
the basic modulation systems. High Power density digital modulation signals
do not work well when there are weak or multiple signals present. 

The AM aircraft band is still with us. The digital world still has not given
us a reliable system to allow for the hearing of a beat telling the A/C
controller there is a weak station present as well as copy the stronger
signal without asking the stronger signal for a repeat.

Art, 
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Tony Langdon
Sent: Saturday, April 23, 2011 2:33 PM
To: Gregg Wonderly; Gordon JC Pearce
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Icom D-Star

At 01:42 AM 4/24/2011, Gregg Wonderly wrote:
>In the end, digital compression of spectrum space is going to happen more
and
>more.  AM style broadcast is hugely inefficient even though it is painfully
>simple to do.  I don't really believe that D-Star is the right choice for
>"everything" because it is single source.  But, so is Microsoft windows,

There's no "one size fits all.  D-STAR has its place, and being the 
new kid on the block, it's open to a lot of tinkering.

>MacOS-X, and many other software based systems.  If you are an FPGA 
>programmer,
>perhaps you can build an FPGA based CODEC for amateur radio that 
>would do voice
>compression etc.  But in the end, you also have to have an 
>transmitter with the
>appropriate bandwidth output to reduce the spectrum used.

Well, maybe one day someone will package something like Codec2 into a 
chip.  That will be a good day for ham radio, BUT it'll never make 
D-STAR.  Why?  Because it's not in the spec and will break the 
existing installed hardware base.  However, the future is likely to 
consist of "multimode" radios, which can handle multiple codecs and 
protocols, and which will be capable of having a yet unknown cocecs 
installed in the field.  Also, eventually the DVSI patent will run 
out, just like the patent for SSB did many years ago.

>The simple fact is that HAM radio emission standards (simple voice
modulated
>with some simple emission standard) are now more than a century old.   As

Not quite.  CW certainly is, AM is around the century mark, I think 
SSB is a little over 80 years old from its first conception, and FM 
is 75 years old. :)

>capable as they are, the abilities they present seem minimal to 
>some.  I think
>that there are great things about them because they do allow long distance
>communications which the HAM community regularly uses to support distant
>operations which provide aid to areas struck by natural disaster.

I think this is one area where ham radio will be increasingly 
important.  Alongside the newer modes, it can also be a living 
"museum" where older modes can live on.  The only mode that hasn't 
survived is spark gap Morse, because it's so spectrally inefficient 
it became illegal.  So ham radio, while it still does advance the art 
also preserves the art as well, and both are important functions to 
me.  If something happened that required falling back to older analog 
modes, there's a pool of experienced operators on hand, who know he 
quirks that the commercial world will forget.


>But, we all have to understand that it costs money to do anything "new and
>different".  People experimenting with stuff is great, but it 
>minimizes who can
>participate if you have to "build it" or "pay a lot".   That's just life in
>general.  You can't participate in everything unless you have the 
>resources to
>do that.

And there's experimentation.  I don't have the background and 
resources to play at a low hardware or software level, but at a 
higher level, equivalent to "mashups" on the Internet I have played 
and still do.


>In the US, any digital communications that is coded in some way only needs
to
>have a publicly visible document detailing how it works for the FCC 
>regulations
>to be met.   Other places in the 

[amsat-bb] Re: In-flight iPhone snaps Space Shuttle launch

[Art McBride]

So what happens to this airplane when it flies near a FM or TV broadcast
station? FAA rules call for EMI testing using 1 amp RF currents in wire
bundles in the aircraft. 

This Cell Phone / computer/electronic interference from consumer electronics
is a compilation of half truths, myths and deception. A shameful compilation
of rules designed to intimidate from an origination that should be
scientific in nature, and totally understand electromagnetic radiation.
Maybe it is the "Federal" part in the FAA name that explains this behavior!

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of George Henry
Sent: Friday, May 20, 2011 2:35 PM
To: AMSAT
Subject: [amsat-bb] Re: In-flight iPhone snaps Space Shuttle launch

And what was her iPhone doing turned on during approach?  Still a no-no on
all 
commercial carriers, AFAIK...


George, KA3HSW



- Original Message 
> From: Clint Bradford 
> To: AMSAT BB 
> Sent: Fri, May 20, 2011 2:20:44 PM
> Subject: [amsat-bb] In-flight iPhone snaps Space Shuttle launch
> 
> The story behind the photo taken of the Space Shuttle from an in-flight 
>passenger jet. Stefanie Gordon shot the image of Endeavour's launch with
her 
>iPhone as her plane descended for a landing.
> 
> 
>
http://www.tuaw.com/2011/05/17/in-flight-iphone-snaps-space-shuttle-launch/ 
> 
> 
> 
> 
> Clint Bradford
> clintbradf...@mac.com


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[amsat-bb] Re: FD Mess

[Art McBride]

Robert,
 One or two contacts during an emergency could be life or death to someone.
The contact that gets through at the right time is the only one that counts.

FO 29 and VO52 are so lightly populated that you most always hear yourself
and on one else. But on Field Day there is blood in the water and the sharks
are feeding!
Art,KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of R Oler
Sent: Monday, June 27, 2011 11:40 AM
To: ni...@ngunn.net; w...@hotmail.com
Cc: Amsat BB
Subject: [amsat-bb] Re: FD Mess


Exactly.  Why  anyone would think that an FM bird in LEO is a viable means
of emergency communications is beyond me.  And then past that if it was the
"only means left" why anyone would be surprised that the people needing the
comm capability (such as it is) are not going to use whatever ERP it is
going to take to get into the bird is beyond me as well.  

Most of the complaints strike me as silly.  With the technical limitations
of an FM bird in LEO the notion of expecting anything different then what
exist now is almost tooth fairy like.  In the end if FM birds are what the
folks and organizations who build satellites want to launch, this is the
kind of "operating" environment that they are going to encourage.  The
argument that "we have to build satellites" that are popular is self
fulfilling.

Robert G. Oler WB5MZO (life member ARRL, AMSAT NARS)


> From: ni...@ngunn.net
> To: w...@hotmail.com
> CC: amsat-bb@amsat.org
> Subject: [amsat-bb] Re: FD Mess
> 
> A bigger FD problem is that FD is advertised as a chance to demonstrate 
> your emergency comms ability to Joe Public.
> FD is NOT a contest so why are points and bonuses  involved at all?


  
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[amsat-bb] Re: FD Mess

[Art McBride]

Jeff,
The way to fix it is to get the ARRL to drop the 100 Bonus points for the
first satellite contact. Then we can talk to ourselves on Satellite with 0
days of chaos!

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Jeff Moore
Sent: Monday, June 27, 2011 4:23 PM
To: AMSAT
Subject: [amsat-bb] Re: FD Mess

You raise an interesting point and something I've wondered about for some 
time now.

IF the sat operators are always so bent out of shape when someone actually 
uses the sats, then why the heck does AMSAT promote a parallel Field Day 
event with ARRL's Field Day??

I think it's about time for AMSAT to have their OWN Field Day Event ON A 
SEPARATE WEEKEND!!!

That way the "serious" sat operators can play all they want on their linear 
birds and leave the FM sats for the ARRL Field Day participants.  Then AMSAT

can have it's own Field Day (or SAT DAY) with it's own rules, like a 100 pt 
bonus for working 2 or more qso's on a linear bird or a 200 pt deduction for

working an FM bird, etc.

73,

Jeff Moore  --  KE7ACY
CN94
Shields Up!

- Original Message - From: "Diane Bruce" 
Subject: [amsat-bb] Re: FD Mess

I know I am going to get hate mail again. I just know it. But here goes.
I've been quietly suggesting that we should _not_ be encouraging sat use
during field day, furthermore we probably should consider turning them
off during field day to stop this.

Now hear me out before you hit that reply key. Field day operators
are interested in those bonus points, we (amsat) are interested in
promoting amateur radio sat operations. How many of these field day
operations actually result in new satellite operators? Where are the
surveys, stats? Does the extra massive battery use of our sats justify
the PR? Keep in mind the state of AO-51 and FO-29.

Am I the only one? I'd be interested in a non-flame war discussion.

- 73 Diane VA3DB
-- 
- d...@freebsd.org d...@db.net http://www.db.net/~db
  Why leave money to our children if we don't leave them the Earth?
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[amsat-bb] Re: FD Mess

[Art McBride]

Joe ,
The ARRL maintains that because they do not give awards it is not a contest.
But like a duck they publish the scores with earned bonus points. Same
deception we get from politicians that are also East of the Hudson!

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Joe
Sent: Monday, June 27, 2011 4:23 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: FD Mess

I know the ARRL  says it is not a contest.  but if you believe that I 
have a lovely swamp in Arizona to sell you.

I know many clubs that it is a MAJOR contest for them and some it's the 
onluy one they enter in.

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 6/27/2011 1:21 PM, Nigel Gunn wrote:
> A bigger FD problem is that FD is advertised as a chance to demonstrate
> your emergency comms ability to Joe Public.
> FD is NOT a contest so why are points and bonuses  involved at all?
>
> On 27/06/11 19:13, Bill Acito W1PA wrote:
>> I think we have to let go of the mantra that "any use of the bandwidth is
good use" with respect to  "encouraging more satellite activity". Wasn't
that the original intent of the "100 point bonus" items? To encourage
specific activities - traffic handling, promotion, emergency power, etc.
>>
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[amsat-bb] Re: FD Mess

[Art McBride]

K6YK,
FD has always been a mess, A mixture of new and old amateurs good and bad
operators and the majority just trying to learn. We had several ex Amateurs
stop by our FD site, some were just looking others helped and operated. We
may reactivate some. SSB birds sound like 20 Meters, huge pile ups. I hate
to tell them that will only happen, one day a year. 

KO6BT got started in satellites at a PARC FD using a station I put together
with home brew antennas on a 6' step ladder. He worked a JA on AO-10 CW. He
was really excited. So FD has a purpose, introduction lies beneath the
attraction of chaos. 

I think more operators would work the linear transponder satellites if
better equipment was available. The stuff from the big three in Japan does
not give the user what they need. The best receiver with the most features
is tied to the transmitter leaving the operator with an under performing sub
receiver for listening. The list goes on. Tracking programs are helpful, but
s means of checking the beacon level and a means of easily adjusting your
power level are not always provided. Responses of digital knobs playing
analog are hard to deal with until you get use to the delay of your radio.
Quick tuning is nearly impossible.  

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of k6yk
Sent: Monday, June 27, 2011 2:02 PM
To: gordon...@gjcp.net
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: FD Mess

 
FD is a mess every year. No matter what bird(s) you try. 

Most of the FD stations have no clue about satellites, they just get 
the idea they need to make 1 satellite contact or as many as they can. 
They don't know about all the rules particular to AMSAT, and they 
dont' care. 

They ask somebody what frequency to transmit and listen on and then
they get their 500 watt amp, big beam or no beam, no preamp, and 
start calling and calling. They don't hear anything so they just mess up
the
whole works.  Happens every year. 

You either have to bear with it and make your one contact or give up.

73, 
K6YK


On Mon, 27 Jun 2011 21:33:34 +0100 Gordon JC Pearce 
writes:
> On Mon, 27 Jun 2011 13:48:48 -0500
> Patrick Green  wrote:
> 
> > The ARRL should impose an ERP limit for satellite contacts.  That
> > would solve the problem.  I don't see how running amplifiers on FD 
> is
> > in the spirit of what FD is all about.  I've made contacts using 
> 50 mw
> > so why do stations use 100+ watts *before* the antenna..  I 
> wouldn't
> > want my kids playing around a FD site with this time of setup.
> 
> Wouldn't that be AMSAT's job?  It's certainly possible to work an FM 
> bird with 5W from a handie, and a hand-held yagi.
> 
> I don't understand the obsession with having all-singing-all-dancing 
> computer-controlled setups, where it automatically updates its 
> orbital elements, automatically calculates when the next pass is, 
> automatically calculates where to steer the aerial and what to tune 
> the radio to and leaving the operator to just push the PTT and shout 
> over the top of the QRP/P stations.
> 
> All the computer-controlled stuff just plain isn't amateur radio.  
> If you want to sit in front of a computer and talk to people, use 
> Skype.
> 
> Gordon MM0YEQ
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[amsat-bb] Re: 70cm Helicoil Good/Bad expensive?

[Art McBride]

Greg,
Do not overlook the 2.4 GHz grid dishes. I have successfully added a quad
loop for 23 cm (1.2GHz) and have been pleasantly surprised with the
performance. I have used one for transmit on 2.4 and receive on 1.2 for ATV
work. A single dish with two microwave bands.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Greg D.
Sent: Monday, July 11, 2011 9:14 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive?


I second Jim's assessment here.  Helical antennas are the only way I will
build an antenna at 1.2 ghz or higher.  It's not worth the stress trying to
measure things to the precision needed for a Yagi at those frequencies.  The
less stress (and time) taken to build the antenna, the more enjoyment you
will get from actually using it!  

For 2m and 70cm, Yagis are good, but also consider making a Quad or a Quagi
(a 2 element Quad with more Yagi elements in front).  I used a home-built 8
element Quagi from the ARRL Antenna Handbook for several years as a
satellite antenna, until I found a crossed Yagi antenna at a Ham Swap for a
price I couldn't pass up.  Still have the Quagi, just in case.

Greg  KO6TH


> Date: Tue, 12 Jul 2011 01:38:17 +
> From: kq...@verizon.net
> To: amsat-bb@amsat.org
> Subject: [amsat-bb] Re: 70cm Helicoil Good/Bad expensive?
> 
> A "Helicoil" is a threaded insert used to repair stripped threads.
> 
> I think you're asking about a HELICAL antenna.
> 
> They work very well, and are easy to build. They're very forgiving in 
> construction errors, but have a few pitfalls you want to watch out for.
> 
> You do NOT want to wind one on PVC pipe for a support, as the dielectric 
> constant of the PVC will throw off the antenna from the design numbers 
> you use to wind the "coil".
> 
> This type of helical is called an "Axial Mode" antenna. A "Normal Mode" 
> helical is how a rubber duck is made, and is not what you want.
> 
> The ARRL Antenna Handbook has several designs that work well, and 
> there's a TON of information on the Web about building an "Axial Mode 
> Helical Antenna".
> 
> They're fixed polarization, determined when you wind it, and the only 
> way to switch between left-hand and right-hand is to have another 
> antenna, and switch to it.
> 
> I've built several, and they work pretty well. They get pretty big at 2 
> Meters, but are manageable (at least for me!) at 70cm and up.
> 
> 73, Jim  KQ6EA
> 
> 
> On 07/12/2011 12:39 AM, Kevin Deane wrote:
> > Hello all, whats the take on these antennas? I am sure someone on here
has used them and they certainly look cool but how do they perform?
> >
> > Dont you have to switch polerization on a cross polerized yagi?
> >
> > I know there is not a perfect antenna, just wondering about the
Helicoil...
> >
> > Kevin
> > KF7MYK
> > 
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[amsat-bb] Re: ARISSat-1 battery eclipse voltage decreasing

[Art McBride]

Dave,
A simple switching inverter connected to the solar cells with multiple
windings would prevent over charging as the voltage output would be
regulated to the voltage of a single cell and the windings providing
isolation between cells. This would insure an equal charge to each cell
preventing early battery failure. Using FET switches for rectification can
boost efficiencies to over 90% even using input voltages as low as 2 Volts
D.C. 

Art, 
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Dave Guimont
Sent: Saturday, August 13, 2011 6:11 PM
To: Phil Karn
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: ARISSat-1 battery eclipse voltage decreasing


>
>Disclaimer: what follows is entirely my own personal opinion, not
>necessarily that of the ARISSat-1 team or anyone else. I might be
>missing information that would affect my analysis.
>
>Ken's plot is extremely valuable. It strongly suggests battery failure,
>not a negative power budget as Tony, AA2TX suggests. Note the sharp and
>consistent *increase* in daylight battery voltage that occurred late on
>Aug 11, roughly coincident with sharp *decreases* of voltage during
>eclipse and reports of computer resets and extended low power operation.
>This is inconsistent with a negative orbit-average power budget. If that
>were the case, the battery would never reach full charge and the voltage
>would never rise so high.

Phil,

How about you designing circuitry/program to charge "cells" 
individually rather than the "battery".  Or has that been tried??

73 Dave




73, Dave, WB6LLO
dguim...@san.rr.com

Disagree: I learn

   Pulling for P3E... 
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[amsat-bb] Re: Turn off AGC when receiving BPSK-1000

[Art McBride]

Phil,

If you have access to the December 1970 issue of the Microwave Journal there
is data on a 1 wavelength, 1 turn Quadrifilar Helix with a beam width of
greater than 180 degrees. Only the 1/2 turn 1/2 wave is popular today, the
140 degree beam with offers the best front to back ratio @ 0.3 axial
wavelengths.
Art,
KC6UQH  


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Phil Karn
Sent: Thursday, August 18, 2011 10:44 PM
To: Dave Guimont
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Turn off AGC when receiving BPSK-1000

On 8/18/11 10:31 PM, Dave Guimont wrote:

> That's why the quadrifilars work so well. I measured the pattern some
> time back, and the "beam width" is about 140 degrees

Yes, something with that kind of beamwidth would be ideal on the
nadir-facing surface of a stabilized satellite in low earth orbit. It
would be even better if the gain in the straight-down direction could be
reduced in favor of gain at the edges. Ideally you'd have a constant
power density over the entire visible earth.

You could of course use a much more directional antenna on the ground if
it can track the satellite.

--Phil


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[amsat-bb] Re: Good mobile antennas to use

[Art McBride]

Just to be fair, I have two comments on the Quadrifilar Antenna.
1. If the satellite is circular polarization the 19.5 " whip looses 3 dB of
gain.
2. The common Quadrifilar Antenna is 1/2 wave 1/2 turn. The 1 wavelength,
1 turn Quadrifilar Antenna has its highest gain near or at the horizon
depending on the length to diameter ratio. 

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob Bruninga 
Sent: Wednesday, September 14, 2011 7:31 PM
To: AMSAT-BB
Subject: [amsat-bb] Re: Good mobile antennas to use

>> The problem is hearing the downlink.  That is 
>> why the 19.5" whip is so good... and has 
>> almost 7dBi gain above 30 degrees up to over 70.
>> So it beats a quadrifilar easily...

> As an example, my last four AO-51 passes were 
> 36, 15, 26, and 27 degrees -max- elevation. 
> Would you prefer gain at low to mid elevations, 
> or above 30 degrees to work this satellite today?

We need to be careful to not bring pears and pommegranets into the apples
and oranges comparisons...

Were those 15 to 27 degree passes done with a Quadrifiliar on the downlink?
We need to keep comparisons to apples and apples or oranges to oranges.. not
all the other possibilities.

> A 1/4 wave will work, sometimes, but it is far 
> from ideal for anything but occasional downlink 
> access.

True, It limits operation to passes above say about 25 degrees, and that
does limit you to 2 or 3 passes per day, but at least they will be GOOD
passes that you can hear well with smooth performance across the sky above
that while mobile and with no pointing cappability. (except for a very rare
direct overhead pass above 80 degrees once in a blue moon) which lasts for
less than a minute..

> As Clayton pointed out, it's easy to spot the 
> guys on crappy antennas, as they are the ones 
> missing calls, or transmitting on top of QSOs, 
> because they mistake a loss of signal as a 
> break in the action.

What Clayton referred to were not simple 1/4 wave verticals.  He was
referring to standard "mobile" antennas that have gain on the horizon and
*guaranteed* nulls then between about 10 to 40 degrees (the primary
satellite operating range) or so plus the small null overhead.  By
mentioning the fades, he was clearly referring to these standard gain
antennas.  By definition, a gain mobile antenna has multiple nulls between
the horizon and overhead thus really playing havoc with satellitie contacts.
And that is precisely why a standard mobile GAIN antenna is well known to be
*no-good* for satellite work.

But this is not what a 19.5" whip does.  The 1/4 (3/4) wave 19.5" whip does
not have gain on the horizon (so it is rarely used for terrestrial mobile)
but its pattern is ideal for satellite work on high passes.  It does NOT
then have a null in its pattern that causes the "crappy" contacts, and it
does have plenty of gain above about 25 degrees and it is a smooth
pattern not like the multi lobes of a standard mobile gain antenna.

> PS My satellite grid addiction started in 2000 
> with a DR-605 Alinco and a 1/4 wave magmount, ...
> Since then I've operated mobile from probably 
> 100+ grids on the FM and SSB birds both. 
> It's addictive.

Yes, I think we are actually agreeing.  A 1/4 wave 19.5" vertical works
well.  But a common mobile gain antenna *does not*.  There is a big
difference.

Thanks
Bob, Wb4APR
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[amsat-bb] Re: Amplifier Suggestions?

[Art McBride]

James,
Check out www.rfparts.com
They have several low power amps, 10mw to 7 W most likely you will need two
amps to get to the 75 watt level Select one that is class AB & use an
attenuator in between amps.
Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of James Cutler
Sent: Wednesday, September 21, 2011 8:04 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Amplifier Suggestions?

Hello,

We are looking for a UHF amplifier (430-440MHz) for a transceiver to go from
10 mW to ~ 75W.  Most of the amps were are funding require a much stronger
input power than we can do. Note, it's a transceiver, so we want to be able
to receive through the system as well.  This is for half duplex satellite
communication using a USRP radio.

Do you have any suggested amps?

Thanks,

--James, KF6RFX
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[amsat-bb] Re: knowledge required

[Art McBride]

John,
Yes, things change. So we know how to neutralize an amplifier. Life changes
and we need to adapt to the present World or sit in a rocking chair and
watch it go by.
Amateur Radio still provides many opportunities to learn as long as we are
willing to put forth an effort to learn new things. Satellite modes are only
one of the many modes of operation available to us. Enjoy them while we
still can, and pity those that no longer can.

Art,
KC6QUH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of John Becker
Sent: Saturday, October 22, 2011 1:39 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: knowledge required

I just wish a could have had a free pass when I went after the 
1st class radio telephone back in 1967.

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[amsat-bb] Re: knowledge required

[Art McBride]

Joe,
What did William F Cody say about horsemen that couldn't saddle their horse?
Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Joe Leikhim
Sent: Saturday, October 22, 2011 10:08 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: knowledge required

Whats with these kids today, they can't drive a car unless it has automatic
transmission. Don't get me going about these wimps and their "paddle
shifters". If you can't drive stick shift and double clutch(without
synchromesh), you should just stay home!

-->  SNIP<--

Just give up on trying to explain to some of these drivers! They will never
understand what you, Peter and others on here are talking about...

The way the US has "dumbed down" the drivers license requirements produced
them...

-->  SNAP<--

-- 
Joe Leikhim

Leikhim and Associates
Communications Consultants
Oviedo, Florida

www.Leikhim.com

jleik...@leikhim.com

407-982-0446

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[amsat-bb] Re: This Is a HOBBY people

[Art McBride]

Greg,
It is the Amateur Radio Service. It does have 5 purposes as quoted in Part
97.1

If you buy supplies and work on something you enjoy doing it is called a
hobby. 

If you do it to establish a business we call it work. 

We are Amateurs because we receive no compensation for our efforts, not
because we are unprofessional.

So where is the conflict?

Politicians are famous for finding the facts to support their conclusions. 

I prefer to have all of the cards on the table.

Art,
KC6QUH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Gregg Wonderly
Sent: Sunday, October 23, 2011 5:42 PM
To: Kevin Deane
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: This Is a HOBBY people

97.1 Basis and purpose.-

The rules and regulations in this Part are designed to provide an amateur
radio 
service having a fundamental purpose as expressed in the following
principles:

(a) Recognition and enhancement of the value of the amateur service to the 
public as a voluntary noncommercial communication service, particularly with

respect to providing emergency communications.

(b) Continuation and extension of the amateur's proven ability to contribute
to 
the advancement of the radio art.

(c) Encouragement and improvement of the amateur service through rules which

provide for advancing skills in both the communications and technical phases
of 
the art.

(d) Expansion of the existing reservoir within the amateur radio service of 
trained operators, technicians, and electronics experts.

(e) Continuation and extension of the amateur's unique ability to enhance 
international goodwill.

None of these items say "this is a hobby" nor do they allude to "just having

fun."  I am not trying to say that its just serious in nature, but there is
a 
considerable amount of personal responsibility and focused effort implied by
the 
above points.  Think seriously about the phrase "This is a HOBBY people."
It's 
not "just" a hobby, although there are many things that you might do with 
Amateur Radio that don't focus on the above points.  The above points are
the 
"reason" why the FCC lets you have a license and allows us to use the 
frequencies.  If we don't focus on fulfilling the responsibilities and
charter 
of these points with some effort, we are just riding on the heals of the
hard 
work of others, who do, in fact, have these things at the forefront of their

efforts to do good things with Amateur Radio.

We need to have discussions and we need to focus on the things that do have 
meaning related to the 5 points above.

Gregg Wonderly
W5GGW

On 10/23/2011 3:33 PM, Kevin Deane wrote:
>
> As much as I enjoy the banter, animosity and sometimes really brilliant
posts, I want to remind everyone that this is a HOBBY!
>
> Amateur Radio.
>
> Shut up and have fun, some of you take this WAY TO SERIOUSLY.
>
> Kevin
> KF7MYK
>
>
>   
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[amsat-bb] Re: Rotor

[Art McBride]

Doug,
If you use a 180 Degree elevation rotator no. Passes almost always end up on
one stop or another of the TV type rotators. By offsetting the "N" end of
the rotator to the NE or NW and using the elevation rotator to pick the side
of travel which coverers the current pass will prevent any running out of
rotation during a pass. If you can find a 1&1/2 turn azimuth rotator the
problem goes away completely.

Art,KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of DOUGLAS WILLETS
Sent: Sunday, November 06, 2011 6:28 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Rotor

I am setting up a satellite station and have the following question. Does it
matter if you use a south center or north center rotor. Is there advantages
using one over the other.

Doug.
KE4MSG
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[amsat-bb] Re: Trivia Question

[Art McBride]

Wyatt,
I would say 180. Another question at what North or South latitude is a grid
square, square?

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Wyatt Dirks
Sent: Monday, November 07, 2011 12:14 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Trivia Question


If you on standing on the north/south pole how many grid squares are you in?
 
73 Wyatt AC0RA
 

  
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[amsat-bb] Memories

[Art McBride]

Today in the Mail, I received two QSL cards from November of 2001. One was
from Belgium and the other from Japan both contacts I made via AO-40. Boy do
I miss that Bird! Satellite DX is now limited to Canada and Mexico for my
location.

 

I guess I do not totally understand why it took 8+ years to receive cards
from "The Bureau", but it was a welcome surprise!

 

Happy New Year

 

Art, KC6UQH  

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[amsat-bb] Re: IT/vista

[Art McBride]

IT text screens run fine on Vista. You get a few warnings but ignore them
and it will come up. If you use Dos Box the graphics screens will work but
picture is small and cannot be enlarged. It works good enough to use, handy
to have Sun and Moon for pointing antennas built in . It has been a great
program for me over the years. 

Art, KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob- W7LRD
Sent: Saturday, January 02, 2010 2:11 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] IT/vista



Anyone have any success running IT under Vista?  I have a newer laptop and I
can't make it go.  Use simple english I am not a computer expert. 


  

73 Bob W7LRD 
Washington State AMSAT area coordinator 
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[amsat-bb] Re: Azimuth question

[Art McBride]

Randy,
True North is used as a reference. Magnetic North changes with observer
location and time. A user of Magnetic North is expected to make the
correction to True North. Some satellite prediction programs give position
of Sun and Moon to calibrate your antennas by knowing your Position and Time

Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Randy
Sent: Saturday, January 09, 2010 6:26 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Azimuth question

Is azimuth base on true or magnetic north
When lining up the antenna system for satellites?
When I looked it up, says true north.
Is that true for ALL satrellite tracking software?

One website says 12 degrees 58 seconds West is the magnetic declination.
So does that mean turn my antenna west by that amount from
Magnetic north?

Randy - N2CUA


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[amsat-bb] Re: Azimuth question

[Art McBride]

Dave,
A fraction of a degree per year, and at least once in the history of the
Earth the North and South magnetic poles reversed. 

Art

-Original Message-
From: Dave Guimont [mailto:dguim...@san.rr.com] 
Sent: Saturday, January 09, 2010 11:47 AM
To: kc6...@cox.net
Cc: amsat-bb@amsat.org
Subject: Re: [amsat-bb] Re: Azimuth question

At 11:37 AM 1/9/2010, you wrote:
>Randy,
>True North is used as a reference. Magnetic North changes with observer
>location and time.
>

Art, what does mag north have to do with time??




73, Dave, WB6LLO
dguim...@san.rr.com

Disagree: I learn

   Pulling for P3E... 


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[amsat-bb] Re: Azimuth question

[Art McBride]

Dave,
If you are technically correct or give a rough answer you get nit picked
form on side or the other. Near by magnetic objects can cause serious errors
using the Sun or Moon for alignment solves all problems for both azimuth and
elevation. For near DC 70cm and longer wavelengths a pointing error of less
than 10 degrees is insignificant. 13cm and shorter accuracy becomes more
important. 
Art

-Original Message-
From: Edward Cole [mailto:kl...@acsalaska.net] 
Sent: Saturday, January 09, 2010 7:02 PM
To: Dave Guimont; kc6...@cox.net
Cc: amsat-bb@amsat.org
Subject: Re: [amsat-bb] Re: Azimuth question

At 04:11 PM 1/9/2010, Dave Guimont wrote:

> >Dave,
> >A fraction of a degree per year, and at least once in the history of the
> >Earth the North and South magnetic poles reversed.
>
> >Art
> >
>
>Yes, I'm aware of that, it also rotates about 1° about true north,
>the earth wobbles a bit to change the AZ, but how
>many ham antennas in the world need that accuracy?
>
>And I doubt that the average ham can orient within more than 2° by eyeball!
>
>
>
>
>
> 73, Dave, WB6LLO
> dguim...@san.rr.com
>
> Disagree: I learn
>
>Pulling for P3E...
>
>
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For 144 & 432 that is probably adequate.  On 2400 
the beamwidth of my 33-inch dish is 10.6 deg. 
(24.9 dBi) so keeping a signal within 1dB, 
probably requires 3 deg beamwidth and knowing 
true north with an accuracy of 10% of that results in 0.3 deg accuracy.

Of course if you are doing something like eme on 
1296 with a 16-foot dish the beamwidth is 3.38 
deg. (34.9 dBi).  For eme it is desirable to 
track within 1db of maximum gain which may is 
something like 1-deg. and 10% accuracy is 0.1 
deg.  How would you set up a dish azimuth so that 
it is that accurate to true north?  For eme it 
usually requires comparison with tracking sw for 
location of the Sun or Moon.  At these freq. and 
dish sizes one can detect solar and lunar noise 
to peak onto, then adjust az and el calib. to match tracking sw az and el.

As it turns out my dish digital az-el readout has 
0.1 deg. resolution so that is best I can 
read.  On the Yaesu B5400, one is lucky to 
determine direction within 7.5 deg. for azimuth 
and 3.75 deg. for elevation.  Manually tracking 
AO-40 with the B5400 was very touchy, as fine 
adjustment is near impossible.  But I did refine 
my azimuth positioning using solar noise on 2400.

For 144 or 432 probably the most accurate method 
for calib of azimuth is using a repeater many 
miles away (knowing both its Lat-Lon and your 
Lat-Lon with bearing sw that produces a great-circle bearing).


73, Ed - KL7UW, WD2XSH/45
==
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500-KHz/CW, 144-MHz EME, 1296-MHz EME
DUBUS Magazine USA Rep dubus...@hotmail.com
== 


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[amsat-bb] Re: Good Night, Loran

[Art McBride]

Loran C was only accurate near the US Coast Guard stations that provided the
corrections to each chain. The Correction stations were located where the
lines of position crossed at near right angles. If you were near the end of
the chain the errors could be in excess of 1/2 NM 
The use of differential Loran was popular before differential GPS which
dialed out selective availability just as Loran corrections did for Loran
errors. Loran was always an area navigation system. Good as it was in the
center of its coverage it still only provided coastal navigation. GPS as it
states is a global system you can use it anywhere in the World with good
accuracy. Both of these systems were very good replacements for
non-directional beacons in the 200KHz to 400KHz range that required Radio
Direction Finding technology. 
In the 50's and 60's Fishing Vessels sailing out of Southern California
could find the fishing grounds off of Guadalupe Island by using aircraft
charts and Loran A signals 1H4 from San Pedro and 3H3 out of Galveston Texas
on a Sky wave. Position was relative but got the fleet to the same place. 
Art,
KC6UQH
 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Howie DeFelice
Sent: Tuesday, February 09, 2010 3:03 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Good Night, Loran


Minor clarification, Loran-A was used from WW-2 until it was turned off in
the 1980's I believe. The current system, Loran-C was in commercial use
starting in the late 70's. When Loran-C was used for returning to a
previously stored waypoint, it's accuracy was almost as good as current GPS
and better than the early "dithered" commercial GPS service.

Howie
AB2S
  
_
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[amsat-bb] Re: Membership Benefits

[Art McBride]

Bob,
There are always a few that refuse to pay for anything and spend most of
their time trying to get something for free. 
If you spend a little on AMSAT then you can use the time that would be spent
on finding something for free, learning how to operate Satellites or build
some of the antennas published in the Journal and save real $

Most important is not to give any encouragement to the constant complainers
that never contribute anything to anything.

Art,
KC6QUH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob- W7LRD
Sent: Sunday, March 07, 2010 9:02 AM
To: Joel Black
Cc: AMSAT
Subject: [amsat-bb] Re: Membership Benefits




Hi Joel and all 

-This is a timely question for me.  Yesterday I organized and ran (with the
help of Wayne-W9AE) a AMSAT table at a local hamfest.  I had the opportunity
to meet many local hams both satellite ops and the curious.  I extolled the
virtues of AMSAT and the satellite community in general.  A few points I
noticed as an undercurrent in some of the conversations.  We hams are
generally a frugal bunch and in some cases just plain cheap.  I had several
antennas on display as well as several pictures, one was of an astronaut on
a EVA installing one of our  antennas on the outside of the space station. 
Some of the questions went like this, one guy asked, "do you have to belong
to AMSAT to operate satellites?", can I get this software (Satpc32) free on
line?" "are these books available any where else?"  My response to these and
similar queries was, "see this picture?" what do you think the shipping cost
is?"  "What we do, is rocket science, and rocket science is not cheap".  
How many active satellite operators do  not belong to AMSAT?  How many use
pirated tracking programs.  How many do not contribute "something" to
AMSAT.  Maybe some aspect of of AMSAT ticks you off, so you cut the cord. 
I'm sure some part of the government ticks you off, you don't move to
Canada.  In order for AMSAT and our efforts to succeed it takes money, and
yes probably lots of it.  This event was a learning process for me and in
the future I hope to hone my abilities and create more dues paying and
contributing members.  Finally- "this is rocket science and rocket science
is not cheap. 





73 Bob W7LRD 
Washington State AMSAT area coordinator 

- Original Message - 
From: "Joel Black"  
To: "AMSAT"  
Sent: Sunday, March 7, 2010 6:40:33 AM GMT -08:00 US/Canada Pacific 
Subject: [amsat-bb]  Membership Benefits 

AMSAT-BB, 

I realize what I'm going to get by asking this...  If you were giving a 
presentation to amateur radio operators who know little or nothing of 
AMSAT, what would you list as some of the benefits of being a member of 
AMSAT?  What would be the single most important reason? 


73, 
Joel, W4JBB 
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[amsat-bb] Re: BeeSat at 4800 GMSK

[Art McBride]

D-Star protocol is 4.8kb/sec for voice 1.2 kb for FEC and 1.2kb for data. It
is GMSK data, transmit rate is 3.6KHz max transmission rate, (7.2kb NRZ),
deviation is 1.8 KHz for a modulation index of 0.5.  BW per Carlson's rule
is 7.2 KHz 
A vocoder module provides for the voice compression. The Data side is used
for Call Sign, Name, City/ State, Brag Tape, GPS position, and Texting all
done with voice simultaneously. D-Star is not very successful in mobile
operation. I have had lots of conversations go R2D2 from a truck or car
passing me. From a fixed position range is surprisingly good. When used on a
Satellite this narrow mode I suspect is very sensitive to Doppler as well as
multipath. Circular antennas on both ends will solve multipath, but Doppler
shift must be dealt with.  
Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Nathaniel S. Parsons
Sent: Saturday, April 10, 2010 10:02 PM
To: Tom Azlin N4ZPT
Cc: AMSAT-BB
Subject: [amsat-bb] Re: BeeSat at 4800 GMSK

Ah, thanks for clarifying. Unfortunately, if I understand you correctly, we
would have to talk to our satellite via digital voice, or at 128kbps, which
would be great if we could!

-Nate

On Sat, Apr 10, 2010 at 10:15 PM, Tom Azlin N4ZPT  wrote:

> Well, make that the digital voice part of the protocol. The high speed
> digital data part is up to 128kbps which was not what I was thinking of.
>
> 73, tom n4zpt
>
> Tom Azlin N4ZPT wrote:
>
>> Hi Nate,
>>
>> the D-STAR protocol is only GMSK at 4800 bps and they selected a
>> time-bandwidth product of 0.5. 4,800 bps or 4k8 is perhaps not talked
about
>> as that IS the standard for D-STAR. So the software there might be
>> adaptable.  that is the reason I thought to suggest it.
>>
>> Good luck and 73, Tom n4zpt
>>
>>
>>
>> Nathaniel S. Parsons wrote:
>>
>>> Hi Tom,
>>>
>>> My mind had indeed played a trick on me, and I remembered MFSK as MSK.
>>>
>>> As far as the DStar group goes, I don't see any mention of 4800 bps or
>>> 4k8
>>> kbps on the public page, so if it's not the group's focus, I don't want
>>> to
>>> have to rely on that solution.
>>>
>>> Thanks,
>>> -Nate KC2SVI
>>>
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>>
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[amsat-bb] Re: SSB 70cm Pre AMp

[Art McBride]

Peter,
Signal from your transmitter is de-sensing your preamp. It could be 2 Meter,
white noise, or 3 harmonic. The third harmonic could come from the
transmitter or it could be made by corrosion on the antenna connections. 
I suggest you check all elements and their connections including the antenna
connectors first. Next step is to make or by filters or try a diplexer. If
you make your own filters start with the RSGB VHF/UHF Manual I has great
ideas and practical information for construction of all types of electronics
including filters. 

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Peter Wilson
Sent: Sunday, April 11, 2010 10:51 AM
To: Amsat BB
Subject: [amsat-bb] SSB 70cm Pre AMp

Hi Everyone,

Just set up my station and started to receive all the main satellites, using
a Gulf satellite antenna (2M + 70cm) + SSB 70cm Preamp and FT736R

When I transmit on 2M, especially FM, it's as if the preamp is squelching -
the receive signal reduces significantly. If I turn the preamp off I don't
get the problem, I can continue to hear the received signal.

Any ideas?

Peter Wilson
G8KEK
AMSAT UK 6897
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[amsat-bb] Re: Stacking satellite antennas on top of an HF beam howmuch separation?

[Art McBride]

Michael
At least 1/2 wave for the lowest frequency (38" 2M) if both antennas are
mounted in the same polarity. Nothing if crossed polarity (like arrow
Antenna)

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Michael Tondee
Sent: Monday, April 12, 2010 4:17 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Stacking satellite antennas on top of an HF beam howmuch
separation?

I'm trying to get a Cushcraft  MA5B HF mini beam back up in the air.
What I'd like to do is  use my azimuth rotator to rotate it and mount my
elevation rotator and Homebrew 2M and 70CM "cheap yagis" up above it on
the same mast. Aside form the obvious distance it will take to keep the
VHF/UHF array from hitting the HF array during elevation changes, what
is a rule of thumb for separation distance to keep the two systems from
interacting with each other? Like so many things, this is something I
used to know but seem to have forgotten in my old age.
  Tnx and73,
Michael, W4HIJ
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[amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

[Art McBride]

dBi is used in range calculations because a isotropic antenna has an even
radiating field leaving only distance as a variable when calculating path
loss. After determining the path loss for a given distance, the antenna
gain, transmit power, receiver sensitivity, receiver noise, cable loss, and
connector losses are factored into the equation to give a link budget. With
the excess allocated to fade margin. 
ERP calculations are used by regulatory agency's to determine possible
interference.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Edward Cole
Sent: Thursday, April 22, 2010 8:47 AM
To: w...@arrl.net; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

At 02:20 AM 4/22/2010, Stephen Melachrinos wrote:
>Ah, but this focuses on my question: Why is ERP referenced to a 
>dipole? Why did someone assume that Arecibo's stated gain of 60 dB 
>was dBd and not dBi? I've never seen the gain of a dish antenna used 
>in satellite work quoted in dBd. All of the references for 
>calculating gain are based on the isotropic reference. And all of 
>the usages I have seen (in professional satellite work) use ERP and 
>EiRP interchangeably, and the i in EiRP is used to explicitly state 
>"referenced to isotropic."
>
>In fact, the amateur community is the only place where there is a 
>fascination with the dipole reference.
>
>The dBd specs are useless for any real calculation purposes. Satcom 
>engineering is much simpler if everyone quotes isotropic, and all 
>commercial/government/military satellite link budgets are based on 
>isotropic references.
>
>Steve Melachrinos
>W3HF
>(Professional) Satcom Engineer since 1979
>
>
> > "ERP is about 243 MW" and
> > that comes from the conversion from dBi to dBd.
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In fact the first gain number published over a month ago was 58 
dBi.  Then I suppose a bunch of hams complained that they didn't 
understand isotropic gain so the Arecibo folks kindly converted the 
number to 60 dBd.  (i.e. unity isotropic gain, dBi=0, is what a true 
omni-directional antenna produces in free space)

Does anyone on this reflector know the formula for calculating gain 
of a parabolic dish (Yes, I know-I'm asking if you know)?  Did you 
know that Arecibo dish is spherical and not parabolic?  So we can 
only use the gain number they provide (BTW the UHF line-feed corrects 
for spherical aberration of the dish surface at Arecibo).  Arecibo 
can track a small amount of angle "because" the dish is 
spherical.  It is my understanding (might be wrong on this) the 
line-feed can adjust for the amount of surface irradiated (which will 
change the gain).

The formula normally used in radio astronomy and mw engineering is in 
terms of dBi.  Most (not all) eme hams use dBi vs dBd.

I am really amazed at this thread on amsat-bb.  I thought the 
satellite community was more globally oriented (International).  The 
different convention in expressing decimal numbers (aka using comma 
or period) is pretty well known (I thought).  US/UK use period and 
most EU use comma.

Most antenna analysis sw express gain in dBi


73, Ed - KL7UW, WD2XSH/45
==
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010
DUBUS Magazine USA Rep dubus...@hotmail.com
== 

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[amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

[Art McBride]

The mathematical model is well proven. The difference between a isotropic
and a dipole antenna is 2.1 dB. The practical accuracy of field strength
measurements on a antenna range is +/- 3dB, making this whole discussion
theoretical. (Just In The Interest Of Science) or JITIOS!
Art,
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Nigel Gunn G8IFF/W8IFF
Sent: Thursday, April 22, 2010 6:15 AM
To: w...@arrl.net
Cc: amsat-bb@amsat.org; Stephen Melachrinos
Subject: [amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

I guess because it's impossible to build an isotropic radiator and therefore
just as impossible to measure it.
Why would I believe, or want to use, something I can neither have, use or
measure?

An isotropic antenna doesn't exist.

On 22-Apr-10 10:20, Stephen Melachrinos wrote:

> In fact, the amateur community is the only place where there is a
fascination with the dipole reference.
>


-- 
Nigel A. Gunn,  1865 El Camino Drive, Xenia, OH 45385-1115, USA.  tel +1 937
825 5032
Amateur Radio G8IFF W8IFF (was KC8NHF),  e-mail ni...@ngunn.net   www
http://www.ngunn.net
Member of  ARRL, GQRP #11396, QRPARCI #11644, SOC #548,  Flying Pigs QRP
Club International #385,
Dayton ARA #2128, AMSAT-NA LM-1691,  AMSAT-UK 0182, MKARS,  ALC,
GCARES, XWARN.

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[amsat-bb] Re: Doppler Tuning Convention Question

[Art McBride]

I have seen it work with Sat PC 32 on VO52 Arm chair copy just move the
antenna once in a while. This was out doors, using a small ACER computer and
arrow antenna. 

I would like to try it on my ICom 720, but the data port does not work just
like everything else that is satellite related to that radio. 
When we get a HEO I will consider replacing the 720, until then no sense in
trying another radio with features that do not match the needs of the
operators. 

Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Gary "Joe" Mayfield
Sent: Monday, May 31, 2010 7:05 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Doppler Tuning Convention Question

Tim,

 Speak for yourself :-)  In the 20+ years I have been a satellite
operator, I have never gotten computer doppler control to work right on the
linear birds.  It works great on FM, but I always wind up fighting it on the
linear birds.  As soon as I tune the other guy in the computer moves me off
frequency.  It's so much easier to just listen and adjust on the fly.

Maybe there is some secret, but I have yet to be clued in...  If
someone wants to write a "Dummies Guide" for this I would be willing to be
your test subject.

73,
Joe kk0sd

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Tim - N3TL
Sent: Monday, May 31, 2010 8:42 PM
To: apbid...@mailaps.org; 'John Belstner'; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Doppler Tuning Convention Question

Alan, John and all,

There is no question that computer-controlled Doppler tuning makes working
the linear satellites easier. That being said, I am glad that my lack of a
computer to dedicate to ham radio forced me to learn and use manual tuning
by following the one true rule of always tuning the higher frequency.

These days, I often use SatPC 32 for computer control when I use my two
FT-817 QRP rigs for the satellites. But last year, right after Field Day,
the CAT plug on my FT-857D stopped working. Because of the choices I've made
about my station setup (i.e., a totally portable station that I can set up
and operate anywhere at any time), I need to use the 857 as a transmit radio
in order to work the DX into Europe and Africa that I have on AO-7 Mode B.
And without its higher power on 2 meters, I would not have gotten Hawaii
into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the
CAT plug died on the 857, I have been manually tuning on every pass during
which I use that radio. 

I really like being able to do it, even if I don't have to. I hope new
satellite operators will take the time to at least develop the basic ability
to effectively use manual tuning. But then - dinosaur that I am - I also
wish more amateurs in general would at least learn Morse Code at slow speeds
... hihi.

And since we're on the topic ... has anyone else noticed that the latest
edition of "The ARRL Satellite Handbook" uses VO-52 as the example for
Doppler tuning - and that it suggests that newcomers who are manually tuning
for Doppler park their transmit frequency on the UHF uplink and tune the VHF
downlink (i.e., the exact opposite of the One True Rule)? That is really
mystifying and disappointing.

Alan, I have no doubt that you're right about the necessity for Doppler
control above Mode B satellites. Having always preferred the KISS approach
whenever possible, I suppose that's why I haven't been able to get myself
very excited for L- and S-band opportunities. I definitely enjoy the
benefits of computer control for Doppler. I just don't much care for having
no choice in using it (or not) to effectively work a satellite.

73 to all,

Tim - N3TL


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Alan P. Biddle
Sent: Monday, May 31, 2010 6:07 PM
To: 'John Belstner'; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Doppler Tuning Convention Question

John,

MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what
has been called the One True Rule.  The usual name for the implementation is
Full Doppler Tuning.  You are doing it right.  When everyone does this, it
provides a very pleasant opportunity to talk instead of tune.  It also keeps
from drifting all over another QSO, though the transponders are seldom full
these days.

However, that is not to say that people not using this are doing it wrong,
exactly.  There are still many rigs in use which do not have the capability
for computer frequency control.  In the old days, the rule was to tune the
highest frequency, whether uplink or downlink, since this is where the
Doppler shift is greatest.  Take a look at KB5MU's original article and
updates here:

http://www.amsat.org/amsat/features/one_true_rule.html

My suggestion is to use full tuning until you find that the other operator
isn't.  Then adapt, usually by turning off the updating for the lower
frequency.  

[amsat-bb] Re: Arrow antenna will not unscrew, help

[Art McBride]

Bill,
A product called Kroil from Kano Labs is the best penetrate I have found.
Some heat helps too, but not enough to anneal the aluminum.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of B J
Sent: Wednesday, June 02, 2010 9:32 AM
To: Bill Dzurilla
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Arrow antenna will not unscrew, help



> We are leaving today for Europe and
> of course I waited until the last minute to take down my
> Arrow antenna, which has been mounted outside for about a
> year.  But, when I attempted to unscrew the elements,
> they would not budge, even after receiving a big dose of
> WD-40.  And the elements are not that solid so it's not
> possible to use a great deal of force.
> 
> Is there some trick to unscrewing these things?



I've loosened corroded threads after applying penetrating oil and then
*gently* applying torque.  Usually I was successful, though I sometimes had
to repeat the process.

After disassembling the elements, it might be a good idea to remove the
threaded stud and run a tap down the holes at the ends of the shafts to
clean them out.  I also recommend cleaning the external threads with a wire
brush or running a die over them.

If the latter doesn't help, replacement studs might be available at places
such as hardware or building supply stores or automotive parts dealers.  If
not, they could be made by cutting ready rod to length and beveling the
ends.

To prevent the threads from binding in the future, there are compounds
available just for that purpose.  A building supply store might have
something like that for threaded pipe.  Just dip the external thread in it
and screw the element back together.

I hope this helps.

73s

Bernhard VA6BMJ @ DO33FL



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[amsat-bb] Re: CP antenna from 2 WiFi panels

[Art McBride]

I have made a LH circular patch for 2.4 GHz and mounted it as a feed for a
1'prime focus dish. I have successfully used it on AO 51. The Patch is in
air with 1/4 " spacing, The active element is rectangular with 2 opposite
clipped corners. It has less than 1 dB of axial ratio. It is fed near one
corner at the 50 Ohm point. 

Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of John Belstner
Sent: Monday, June 07, 2010 8:47 PM
To: Greg D
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: CP antenna from 2 WiFi panels

Hi Greg,

What I meant by "at best" is that it will certainly be a challenge (at 2.5
GHz) to get one panel just a perfect 1/4 wavelength forward from the other.
It will be equally as challenging (at 2.5 GHz) to make 75 ohm phasing cables
some odd multiple of 1/4 wavelength.  

I say that because I found it quite challenging to make phasing cables for
1.3 GHz and even 440 MHz and I had a network analyzer to help me.  Just when
I thought I had it cut perfect I put the connector on and found myself 10 to
20 degrees off.  That will affect the circularity of the polarization.  I
finally gave up and mounted the elements of one yagi 1/4 wavelength forward
from the other and used equal length cables. 

Physical spacing is easier to achieve within a few degrees at the lower
frequencies (VHF/UHF).  Another alternative would have been to use a 90
degree broadband hybrid (that can handle 25 watts) but that was much more $
than I wanted to spend.

If you have a helix already, I would use that.  But don't let me talk you
out of experimentation.  It is possible and might be fun.

73, John


Sent from my Verizon Wireless BlackBerry

-Original Message-
From: Greg D. 
Date: Mon, 7 Jun 2010 20:22:22 
To: 
Cc: 
Subject: RE: [amsat-bb]  CP antenna from 2 WiFi panels


Hi John,

"At best"?  Interesting...  I've seen many diagrams about mounting two
linear YAGIs at 90 degrees from each other on the same cross arm, with the
appropriate phasing harness.  My plan is to mount the two panels the same;
one next to the other, rotated 45 degrees in opposite directions on the
cross arm, with one pushed out 1.23 inches by a block of wood.  How bad will
this be?  One will surely get some elliptical effects when the satellite is
off-axis, but keeping them aimed at the satellite is what the rotor and
computer are for...

I understand that I'm losing some NF by not using a proper splitter, but I
don't have one handy, and this is (was) supposed to be a low effort
adventure.  Again, for AO-51 VS, I should have plenty of margin.

I've built several helixes, both 2.4 ghz for the feed to my BBQ grill, and
my current L-band uplink, and could do the same here.  But, back to the low
effort part of things...

If this simply isn't going to work, then I'll just leave my current setup
alone.  It consists of a 3 3/4 turn helix feeding a 30 inch BBQ grill, lined
with window screen.  All combined, it's kind of heavy, and the wooden cross
arm is showing the effects of the weight and its age.  It was built for
AO-40, and for the current satellites I don't really need this much gain,
hence the replacement idea.  

Bad idea?

Greg  KO6TH




> Subject: Re: [amsat-bb]  CP antenna from 2 WiFi panels
> From: jbelst...@yahoo.com
> Date: Mon, 7 Jun 2010 07:37:17 -0700
> CC: amsat-bb@amsat.org
> To: ko6th_g...@hotmail.com
> 
> Hi Greg,
> 
> These panels are patch style antennas and as such you will not be able to
place one behind the other to obtain circular polarization.  Placing one
next to the other will at best produce an elliptically polarized pattern,
and you should use a 50 ohm splitter to keep your impedance 50 ohms.  The
shape of the patch and position of the feed point is typically how you
obtain circular polarization with a patch antenna.
> 
> Or, you can obtain RHCP with the same or more gain and less trouble by
making a Helix.  A sheet of aluminum, #8 copper wire and and a piece of PVC
of the right diameter is all you need.
> http://brneurosci.org/helix-antenna.html
> 
> Or, you can try just a single panel and see how it performs for a while.
> 
> Good luck!
> 
> 73, John W9EN
> DM13le
> w...@amsat.org
> 
> 
> 
> 
> 
> 
> 
> 
> On Jun 6, 2010, at 1:15 PM, Greg D. wrote:
> 
> > 
> > Hi folks,
> > 
> > Before I start nailing stuff together, I just want to verify what I'm
doing...
> > 
> > I want to make a 2.4ghz Right-Hand Circular antenna from two flat panel
Wi-Fi antennas.  The idea is to mount them at 90 degrees from each other,
with one 1/4 wavelength in front of the other.  Combine the two feeds with a
simple Tee (the feeds are of equal length), and into the pre-amp.  Since I'm
not transmitting, I'm not too worried about the resulting 25 ohm impedance
(or should I be?).
> > 
> > If it matters, the panels are from HyperLink Technologies, their model
HG2414P, with a claimed 14dBi gain.
> > 
> > So, the questions:
> > 
> > 1.  1/4 wavelength at 2401 mhz is ((3 x 10**8 

[amsat-bb] Re: My $0.02 worth

[Art McBride]

While we are collecting cents!
AO-40 a HEO was available for up to 12 hours each pass. Doppler and antenna
pointing happened slowly for most of the pass. I had one antenna on a step
ladder the other on a tripod. A slight adjustment every half hour was all
that was needed. I worked 10 foreign countries and all across the US. I
could set up and work at my leisure as many Stations as I wanted to. 1/2 to
one hour QSO's were common. It was not rush and set up your gear have a 5
minute hair raising QSO experience, controlling Doppler on two frequencies
using one knob, or throwing out a perfectly good operating radio because the
computer control doesn't work.
Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Larry Gerhardstein
Sent: Thursday, June 17, 2010 6:58 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] My $0.02 worth

I don't feel a bit sorry for those who gripe on this BB about there not 
being enough HEO birds, too many FM birds (operators), not enough linear 
transponders, or the like.  Yesterday, I encountered a nice FO-29 pass 
with maxEL about 60 degrees here at my QTH.  I heard no one, yet I could 
hear my CW/SSB downlink signal from the bird loud and clear.  For awhile 
the footprint covered the entire 48 state region.  I thus called CQ for 
nearly 15 minutes, but no one (that's zero, na-da) came back to my calls.

Then later there was a good VO-52 pass and I did manage to work N6PAA, 
very good clear SSB signals both ways.  But during the 10-15 minutes of 
that pass, I heard no one else in a QSO or calling CQ etc.

I think before we start making complaints about the current state of 
affairs, we seriously consider making use of those resources we do have 
at present.  And then make a financial donation to the various AMSAT's 
and teams working to make future birds possible.  We all want another 
HEO with lots of modes/bands, but complaining will not make one 
magically appear.

73, Larry W7IN, DN27, Plains Montana.



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[amsat-bb] Re: Re; Homebrew Polarity Switch

[Art McBride]

Nick,
The circuit you referred to can be simplified. The two 1/4 wave 75 Ohm coax
sections match the two antennas to 50 Ohms. A 1/4 50 ohm line will delay the
signal by 90 degrees for circular polarization. The opposite rotation is
accomplished by adding of a 1/2 wave 50 ohm section to delay one side by 180
degrees. Further simplification when using crossed Yagi's is to space one
Yagi a 1/4 wave behind the other and use only the 1/2 wave section.
The end result is to have one antenna lead or lag by 90 degrees for RH or LH
rotation. 
To make this work both antennas must be the same electrically and any feed
line after the matching sections must be identical lengths to the antennas.
All wavelength calculations use 2952/frequency in MHz times the VP of the
coax for a 1/4 wave in inches. Multiply by 2 for 1/2 wave.
Experiment and build your own.
Amateur radio is learning by doing!

Art, KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Daniel "Nick" Kucij
Sent: Thursday, July 29, 2010 9:11 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re; Homebrew Polarity Switch

> If anyone can point me in the right direction to find this item I  
> would
> appreciate it.  Additionally, if it is something that I could  
> fabricate and
> there is good info available online, please forward any appropriate  
> links to
> me.
>
>


David,

PA3GUO has described a homebrew switch on his website,
http://www.pa3guo.com/ 
 Click on Antennas, then scroll to the Polarity Switch button.

Nick KB1RVT


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[amsat-bb] Re: New Satellite Downlink?

[Art McBride]

In the USA

I am not aware of any Federal law that prevents listening to government
frequencies. They are considered directed communications and can not be used
for personal gain nor be repeated or transcribed by the listener. 

There are many local laws, however as soon as the constitutionality of the
local laws are challenged (Regulatory rights for radio communication are
reserved for the Federal Government) charges are dropped. These laws are
maintained only for their nuisance value.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of David - KG4ZLB
Sent: Saturday, August 28, 2010 3:01 PM
Cc: amsat-bb@amsat.org
Subject: [amsat-bb] Re: New Satellite Downlink?

  I would have to side with Nigel here as my understanding is that he is 
quite correct - you are not allowed to listen into the Police 
frequencies for instance or any other frequency that you are not 
authorized for - maybe you can in Scotland Gordon :-P

As always, I am happy to be corrected though.

David
M0ZLB/KG4ZLB



On 8/28/2010 14:45, Gordon JC Pearce wrote:
> On Fri, 2010-08-27 at 23:40 +, Nigel Gunn G8IFF/W8IFF wrote:
> I don't know where you've been in Europe, but that would be perfectly
> legal in the UK.
>
> Gordon MM0YEQ
>
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[amsat-bb] Re: Antenna Opinions?

[Art McBride]

Greg,
 I would keep the one that works the best. 
I have been disappointed in the performance of long boom Yagi's for UHF.
Resistance loss in the elements often reduces the gain by several dB over
calculated gain. Also they are very narrow band, the helix is good for an
octave.
Art,
KC6UQH
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Greg D.
Sent: Tuesday, September 21, 2010 10:04 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Antenna Opinions?


Hi folks,

So, we had a swap meet a couple of weekends ago, and I found a bargain I
couldn't refuse.  Of course, now I need to decide what to do with it...  

The Find was a 35 element 1296mHz antenna, well built and in excellent
condition.  Linearly polarized, horizontal; supposed to be 23dBi gain.
Manufacturer, of course, is unknown.  No markings, but it does not look
home-built.  By the mounting hardware, it looks like it was part of some
sort of stacked array.

The problem is that I already have a 1296mHz antenna.  Home-made, circularly
polarized, 18 turns Helix.  Should be something like 17dBic, if the
calculations are correct.

In the shack, which is at the wrong end of 60' of 1/2" hardline and a total
of about 15' of RG-213 or something like it, I have my Yaesu 736R and its 10
watts of screaming RF power.  No preamps.

Which antenna should I keep up on the rotor assembly?

Last weekend I put up the new antenna.  I've made one AO-51 LU pass with the
new antenna, and I was not impressed.  Several times I couldn't get into the
bird, presumably because of the crossed polarization.  But when I did get
in, it was full quieting, even at low elevations.  I don't recall having
this much trouble with the Helix.  I think AO-51 is the only current
satellite on L-band, right?

For other uses, there's nothing terrestrial to aim at, repeaters-wise;
they're all hiding behind one or more hills, or went off the air years ago.
That leaves Weak Signal work (hence the horizontal mounting).  I do have one
shot into the valley, to the North West, but probably slim pickings for
contacts.  I haven't tried EME.

I'm leaning towards putting the Helix back up, and passing the new one on to
someone more able to use it.  What are your thoughts?

Thanks,

Greg  KO6TH

  
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[amsat-bb] Re: AO-7 Mode A antennas

[Art McBride]

Jeff, 
Check to see if the 10M band is open in your area. 
Signals from space on 10M will be weak or not heard depending on how good
the 10M opening is. They can't get through the ionization layers when the
band is open. Signals 2M and higher are not effected by the ionization
layers. 
Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Daniel "Nick" Kucij
Sent: Saturday, October 30, 2010 6:04 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: AO-7 Mode A antennas

Jeff:

I have not used an external 10M preamp yet, but I just got an ARR from  
another op, so I'll be giving it a try. So far, I've used my FT-847  
and the internal preamp. It has not been as consistent as Mode B, but  
when the 10M signal is coming in, reception is usually fair to good. I  
have noticed quite a bit of QSB at times, so it's worth being patient.

Nick
KB1RVT
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[amsat-bb] Re: AO-51 S-Band antenna polarization

[Art McBride]

John,
>From the information of the time I researched it soon after AO-51 was
launched, I recall it was linear but polarity was pointing angle dependent.
I used a patch LH rotation feed on a 20" MDS dish with great results using a
KG5NA down converter. Being circular there was one less variable to contend
with during the short duration passes of AO-51. The gain of the dish with
the low noise figure of the down converter more than made up for the 3 dB
loss from linear to circular. 

Art,
 KC6UQH



-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of jmfranke
Sent: Tuesday, December 21, 2010 11:57 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] AO-51 S-Band antenna polarization

Does anyone know the polarization of the 2.4 GHz transmissions from AO-51. 
Are they circular?  If so which polarity, RHCP or LHCP?  Are they linear? 
If so is there a preferred receiving polarization?  I have examined the 
AMSAT web site and many references on the Internet, but cannot seem to find 
the answer.

Thanks,

John  WA4WDL  AMSAT member 10211 


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[amsat-bb] Re: Fw: Stop flaming please

[Art McBride]

In Part 97 of the FCC Rules (USA) states one of the purposes of the Amateur
Radio Service is to promote international goodwill. We as Amateur Radio
Operators should all be mindful of our relationship to Amateur Radio and
practice goodwill in all of our communications both internationally as well
as domestically. 

A few apologies from the active participants would be appreciated and
provide for closure of this ugly thread.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Roger
Sent: Saturday, December 03, 2011 9:49 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Fw: Stop flaming please

I don't think that it is appropriate language or a civil response. The 
author should be moderated.

Roger
WA1KAT

On 12/3/2011 2:26 PM, andy thomas wrote:
> I don't think this is the spirit of informed and reasonable debate.
>   
> 73 de andy g0sfj
>
> - Forwarded Message -
> From: Kevin Deane
> To: andythomasm...@yahoo.co.uk
> Sent: Saturday, 3 December 2011, 19:15
> Subject: RE: [amsat-bb] Stop flaming please
>
>
> shut the fuck up dumbass, there will be nobody there on FM
>
>
> Kevin
> KF7MYK
>
>
>   
> Date: Sat, 3 Dec 2011 16:35:10 +
> From: andythomasm...@yahoo.co.uk
> To: amsat-bb@amsat.org
> Subject: [amsat-bb] Stop flaming please
>
> I don't see why someone can't make a suggestion about a qrp experiment
without being flamed about being incompetent, inadequate,  financially poor
or in some other way a lesser member of the -bb. You guys ought to learn a
little more tolerance.
>   
> Fact #1 is, ao-51 is dead and we don't have anything else of that quality
for all of those operators who like doing field operations with an arrow.
SO-50 is at best unpredictable and AO27 is not always on, depends on its
ssp. Fact #2 is that anyone who is an alligator could have taken over vo-52
and didn't, thankfully. Fact #3 is that nobody would without seeking
permission.
>   
> So please cut back from the snide clever-clever remarks about having too
small a piece of kit, hi. I don't feel bad about raising the idea.
>   
> 73 de andy g0sfj
> ___
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[amsat-bb] Re: 2 Meter TV Interference

[Art McBride]

Charles,
Our Channels 8 & 10 moved the digital channel from UHF to VHF at the end of
the conversion period. Since they had to give up one channel and the
operating costs for the same coverage are considerably less on VHF it was a
easy decision to make. I doubt this is what FCC had in mind, but that is how
it worked out. 

UHF has less noise (Very little galactic noise) and significantly smaller
antennas,(shorter wavelength) making the UHF segment more desirable for
portable operations. Best policy is to use the VHF band for TV and save UHF
for other uses. 

Interesting enough a 5 Watt "S" Band link transmitter carries the video
signal to the local cable TV companies that serve 90% of the viewers. Only
10% receive their TV signals over the air!

That is how it is done in Southern California.

73,
Art KC6UQH  

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Charles Suprin
Sent: Wednesday, December 07, 2011 1:49 PM
To: Bob Bruninga
Cc: amsat-bb@amsat.org; Gordon JC Pearce
Subject: [amsat-bb] Re: 2 Meter TV Interference

I didn't think there were any vhf stations left. All the numbers on the
channels now are virtual. All the tv antenna plans are for uhf bands. A
quick look in the Boston market and the lowest channel is 19, channel
2@500MHz. Are there places that still use vhf?

Charles
On Dec 7, 2011 1:38 PM, "Bob Bruninga"  wrote:

> HPF above 500 MHz?  Then the TV would not be able to see anything but a
few
> UHF channels.
>
> What is needed is a stub filter.  Just a piece of open ended coax 13" long
> "T"ed into the antenna lead
>
> The 13" is about 66% of a quarter wave at 2 meters.
>
> Done
>
> Bob, WB4APR
>
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of Gordon JC Pearce
> Sent: Wednesday, December 07, 2011 3:02 AM
> To: amsat-bb@amsat.org
> Subject: [amsat-bb] Re: 2 Meter TV Interference
>
> On Tue, 6 Dec 2011 21:17:55 -0600
> Wyatt Dirks  wrote:
>
>
> > Just recently I have been having troubles with a neighbor while I am
> working the FM satellites(SO-50 and AO-27). The setup I am currently using
> is my mobile setup because I am unable to put a base station up for many
> reasons. I am using a FT8900 with 50 watts out into a 1/4 wave or 1/2
> Larson
> mobile antenna.The 1/4 wave is mounted permanently via a hole in the roof
> of
> my truck an the 1/2 wave is mounted on a mount opposite the factory
> installed FM/AM radio whip. It doesn't seem to matter what antenna I use
> for
> the problem to occur. Then I use either the arrow antenna or my cju for
the
> downlink.
>
> Use 5W into a hand-held Yagi.  You'll get far better results.
>
>
> > Today I had another local ham over at the request of the neighbor and
his
> mobile Kenwood radio did the same thing to the neighbors tv when he
> transmitted on 2 meter with 50 watts out. He also recommended that they
get
> a filter. I did not see the specs on the filter nor do I know what
> bandwidth
> it was for.
>
> What you want is a highpass filter that will lop off everything below
> 500MHz.  The chances are that your TX output is clean enough but the
little
> amplifier in the splitter for the TV is causing all sorts of intermod -
and
> probably covers from broadcast VHF radio to the top of the TV band.
>
> --
> Gordon JC Pearce MM0YEQ 
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[amsat-bb] Re: Noise from notebook's PSU

[Art McBride]

Andy,
My first suggestion is to one by one disconnect any peripherals that are
connected to the notebook, begin with the battery charger/power-source, and
leave the antenna control wires for last. Watch the "S" meter and determine
the level of interference contribution of each device connected to the
notebook. Ferrites on interfering cables will help if you find that
disconnecting the cable reduces the noise. 

If you still have interference with everything disconnected, first shutdown
any programs that are not used for Satellite operation, then try moving the
notebook to different locations and orientations until the noise goes away.
Move any cables from the radio away from the notebook. If you still have
interference look at the antenna cable, use a quality cable like RG214,
RG142, RG 223 with a double shielded braid, or use 100% shielded cables like
LMR 195, LMR 400. Radio Shack cables are noted for having a single 40%
coverage braid.

Never assume that the noise has only one point of entry. In most cases it
comes from several places, being conducted by wiring and radiated by
circuitry inside the notebook. Newer notebooks have far less radiated
emissions from improved technology. If you are using an old notebook, try to
borrow a newer one and see it the problem goes away.

Good Luck,
Art,KC6UQH


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Andy Brian
Sent: Sunday, December 25, 2011 6:30 AM
To: AMSAT-BB
Subject: [amsat-bb] Noise from notebook's PSU

Hi,

I found that I get a high level of noise on my RX from PSU of the
laptops. I need notebook for my antenna control and I'm looking how to
reduce or minimaze the noise from PSU, any good suggestion are welcome.
thanks
MX and HNY2012
regards Andy
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[amsat-bb] Re: VO-52 in Mode J?

[Art McBride]

I also can confirm VO-52 was active, but I had to use an amplifier during
Field Day, with everyone using power it left my signal in the noise without
it.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of George Henry
Sent: Sunday, June 24, 2012 9:25 PM
To: amsat bb
Subject: [amsat-bb] Re: VO-52 in Mode J?

Must have been a hardware issue at your end, as VO-52 was quite active for 
Field Day.  Remember, its downlink is on 2 meters, while AO-27 and FO-29 
downlink on 70cm, so hearing them would tell you nothing about your ability 
to hear VO-52 (or not).


George, KA3HSW


- Original Message - 
From: 
To: 
Sent: Sunday, June 24, 2012 10:03 PM
Subject: [amsat-bb] Re: VO-52 in Mode J?


[snip]
>
> I dont't know, but I usually have zero trouble working VO-52 during Field 
> Day, but this year I never heard even a peep from it on about a dozen 
> passes that I tried. It felt almost as if the satellite was not there or 
> the transponder was off. Probably an equipment problem on my end, but I 
> was able to hear (but not work) AO-27 and FO-29 a few times, so I know I 
> at least had my Android phone set up properly for making pass predictions,

> and they also matched the pass predictions on AMSAT.ORG online. So, unlike

> prior years, when I've done stupid things like not correct for Daylight 
> Saving Time or updated the station coordinates, I know I at least had 
> those major goofs prevented. But I was shocked and disappointed that I 
> could not even hear the slightest bit of activity or signal return this 
> past weekend. Like I said, this has always been an excellent, reliable 
> linear transponder, so I was particularly surprised...
>
> W0JT (for the W0BU Field Day effort)

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[amsat-bb] Re: One questiong for ant hombrewers...

[Art McBride]

Pavel,
 You may want to consider a one wavelength one turn QFH. Its best gain is
below 30 degrees above the horizon. The pattern is still omni. 

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Pável Milanés Costa co7wt
Sent: Monday, July 23, 2012 5:14 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] One questiong for ant hombrewers...

Hi to all.

I'm Pavel Milanes, CO7WT, from Cuba, member of the GROS.

I have a question in my head and I have not enough arguments to decide, I
have to BUILD my own antennas, so having this into account:

What is the most cost effective (cost / gain / difficult in building / omni
pattern) that can I build?

I have in plans to build a LNA from a servian pdf using the BF998 MOSFET,
that will be at the antenna point, Andrew Heliax LDF-4 50 ohms for the
download to the shack and of course this is a FIXED antenna, with NO rotors.

I have heard of and modeled all this ones and all have his pros and cons...
- QFH
- Turnstile dipoles
- Turnstile moxons (100 ohms)
- Eggbeater

I think (correct me if I'm wrong) that the best election will be the QFH,
because his really omni pattern, beside the fact that I will have to build
two of them (rhcp and lhcp switched properly with a relay) and the lower
gain will be 'compensated' with the LNA...

Please, I don't want to start a flag war, only heard about some experiences
to decide my self.

Last tip, TRX on 70 cm will be a Kenwood channelized TK-382N for FM (5W) and
TRX on 2m will be a Alinco DR-130.

73



Este mensaje ha sido enviado mediante el servicio de correo electronico que
ofrece la Federacion de Radioaficionados de Cuba a sus miembros para
respaldar el cumplimiento de los objetivos de la organizacion y su politica
informativa. La persona que envia este correo asume el compromiso de usar el
servicio a tales fines y cumplir con las regulaciones establecidas.
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[amsat-bb] Re: Antenna Polarization Technical Question

[Art McBride]

Bob,
Just a reminder, a QFH antenna is circularly polarized over the whole
envelope of the antenna. A sharp null exists on the back side. A one
wavelength, one turn has gain at low angle side radiation and a 4 dB loss
overhead, where the distance to the ground station is the smallest.
Certainly this is a good fit for satellites.

Turnstile antennas and patch antennas are linear polarized at the sides and
of course are the easiest to implement on a satellite. 

My point is all circular antennas are not equal and having an antenna with
gain on the sides opposed to the center of the antenna is very desirable.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Bob Bruninga 
Sent: Saturday, August 04, 2012 3:25 PM
To: Thomas Doyle
Cc: amsat-bb@amsat.org; andrew abken
Subject: [amsat-bb] Re: Antenna Polarization Technical Question

> Not sure why anyone would want to maintain the 
> orientation of the satellite in such a way that 
> would cause the direction of circular
> polarization to change during the path. 

Lets try this approach... As I said before,  By the laws of physics, what
comes out one side of a circular polarized low gain antenna as RHCP comes
out the opposite side as LHCP.

Now given that, and the fact that someone in Maryland is in the center of
the RHCP beam, then by the laws of physics, the guy in California must see
mostly LHCP.  No matter how much one of those persons demands that he
deserves the RHCP beam, by definition, someone else somewhere will get the
LHCP one, and the geometry changes at least every 10 minutes or so and every
time the spacecraft rotates a bit.

So one might say, "point it down" then only the person in Kansas will see
the main beam and those in CA or MD will be completely off the sides almost
70 degrees from the main beam.  Mot people do not realize how LOW these
satellites are.  The only solution is to put satellites so high, that "down"
is about the same to everyone (geostationary altitude).  But then that takes
100 times more altitude, and that takes 10,000 times more power.

Better to just live with the laws of physics... I guess.

Bob, WB4aPR

>
>On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga  wrote:
>>> I believe that is true but that does not explain
>>> why the optimum polarity setting on the receive
>>> end would change during a pass.
>>
>> That's easy.  The circularity on a pair of crossed dipoles (about all
you can get on a spacecraft) May be designed for Right hand circularity when
viewed from the prime direction.  But by definition, that save waveform will
be LHC when viewed from the opposite direction.
>>
>> And since the geometry to any one observer is constantly changing by
almost 180 degrees during an overhead pass, that is why it is very easy to
see, complete change in circularity.
>>
>> Bob, WB4APR
>>
>
>
>
>-- 
>
>Sent from my computer.
>
>tom ...
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[amsat-bb] Re: Antenna Polarization Technical Question

[Art McBride]

Domenico,

You are correct, the crossed dipoles fed in quadrature when on axis exhibit
LH and RH circular patterns, but 90 degrees from axis they are linearly
polarized. This gives poor performance at low angles as well as requiring
both RH and LH rotations for a full pass reception. 

Obviously the QFH antenna to be effective should point down at the earth,
with the sides pointing to the horizon and the backside towards outer space.
The one wave one turn can be optimized,(Length to Diameter ratio)to provide
best radiation at the horizon. This will give good performance when the
satellite is near zenith as well as provide improved performance at low
elevations.

Circular polarization does help to eliminate multipath and provide a steady
copy, even while the antenna is mechanically rotating with the satellite for
stabilization and temperature stability. 

Art,
KC6UQH

-Original Message-
From: i8cvs [mailto:domenico.i8...@tin.it] 
Sent: Sunday, August 05, 2012 3:27 PM
To: AMSAT-BB; Bob Bruninga ; kc6...@cox.net; Thomas Doyle
Subject: Re: [amsat-bb] Re: Antenna Polarization Technical Question

Hi Art, KC6UQH

It is correct that a QFH is circularly polarized over the whole envelope
of the antenna.If it is left wound the polarization is RHCP and if it is
right wound the resulting polarization is LHCP.

By the way the point is the satellite antenna.

If the satellite antenna is made using two crossed dipoles mounted in the
same mechanical plane and are supplied with 90° out of phase than the
radiated polarization is RHCP along one axial direction and LHCP along
the other axial direction.

Since the satellite is thumbling orbiting in the space than the polarization
coming from the satellite to earth or coming from the ground station to
the satellite is continuing changing from RHCP to LHCP to linear passing
through elliptical.

The bad point is that a QFH can only radiate RHCP or LHCP depending
on it's winding direction so that using only one QFH the QSB generated
by the satellite thumbling cannot be completely eliminated and two
switchable QFH's one RHCP and the other one LHCP would be necessary.

73" de

i8CVS Domenico

- Original Message -----
From: "Art McBride" 
To: "'Bob Bruninga '" ; "'Thomas Doyle'"

Cc: ; "'andrew abken'" 
Sent: Sunday, August 05, 2012 10:44 PM
Subject: [amsat-bb] Re: Antenna Polarization Technical Question


> Bob,
> Just a reminder, a QFH antenna is circularly polarized over the whole
> envelope of the antenna. A sharp null exists on the back side. A one
> wavelength, one turn has gain at low angle side radiation and a 4 dB loss
> overhead, where the distance to the ground station is the smallest.
> Certainly this is a good fit for satellites.
>
> Turnstile antennas and patch antennas are linear polarized at the sides
and
> of course are the easiest to implement on a satellite.
>
> My point is all circular antennas are not equal and having an antenna with
> gain on the sides opposed to the center of the antenna is very desirable.
>
> Art,
> KC6UQH
>
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of Bob Bruninga
> Sent: Saturday, August 04, 2012 3:25 PM
> To: Thomas Doyle
> Cc: amsat-bb@amsat.org; andrew abken
> Subject: [amsat-bb] Re: Antenna Polarization Technical Question
>
> > Not sure why anyone would want to maintain the
> > orientation of the satellite in such a way that
> > would cause the direction of circular
> > polarization to change during the path.
>
> Lets try this approach... As I said before,  By the laws of physics, what
> comes out one side of a circular polarized low gain antenna as RHCP comes
> out the opposite side as LHCP.
>
> Now given that, and the fact that someone in Maryland is in the center of
> the RHCP beam, then by the laws of physics, the guy in California must see
> mostly LHCP.  No matter how much one of those persons demands that he
> deserves the RHCP beam, by definition, someone else somewhere will get the
> LHCP one, and the geometry changes at least every 10 minutes or so and
every
> time the spacecraft rotates a bit.
>
> So one might say, "point it down" then only the person in Kansas will see
> the main beam and those in CA or MD will be completely off the sides
almost
> 70 degrees from the main beam.  Mot people do not realize how LOW these
> satellites are.  The only solution is to put satellites so high, that
"down"
> is about the same to everyone (geostationary altitude).  But then that
takes
> 100 times more altitude, and that takes 10,000 times more power.
>
> Better to just live with the laws of physics... I guess.
>
> Bob, WB4aPR
>
> >
> >On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga

[amsat-bb] Re: Icom AG-35 Preamp Question

[Art McBride]

Rick,
I suggest you use a VOM or DMM to measure the current drawn on 12 volts
going to the power injector. If everything is connected correctly It will
draw 30-200 mA. Confirm that you have continuity in your coax. Some
lightning arrestors have a DC block built in. It is best to test it with a
short run of coax between the preamp and the power injector at the radio
while listening to a local repeater to see if the signal increases when you
apply power to it. If it operates then you can proceed to determine if there
are problems with the coax to the antenna, not carrying the 12 VDC. 
73
Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Lawn, Richard
Sent: Saturday, August 11, 2012 3:30 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Icom AG-35 Preamp Question

I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it
as virtually brand new and it was/is. I planned to use it this summer with a
TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as
other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to
drive mast mounted the preamp. When I turn the power on there seems to be
little or no noticeable difference in background noise and worse than that I
cannot here any signals on FO-29 downlink, and I know the bird has been
active. Any suggestions? Is the preamp fried? I can't even get the weather
proof case off to trouble shoot, not that I'd know what to look for. Any
suggestions on repair?

TNX
73
Rick
W2JAZ


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[amsat-bb] Re: dismantling satellite antennas

[Art McBride]

TO All,
This is just another thread documenting Pioneers, (the ones with the arrows
in their backs). Isn't this the same as 200 Meters and down that happened
almost 100 years ago? 
The experts at the time decided any communications on frequencies above
1,500 KHz would only carry a hundred miles or so and were useless for most
communications. Everything above 1,500 KHz was given to the Radio Amateurs
to experiment with. Once the experts were proven wrong, the government took
most of the spectrum from the Radio Amateurs, assigning it to commercial and
government interests. 

Amateur Radio Operators pioneered communications by satellite with the OSCAR
satellite series. Communications by Satellite has been led by Government and
Commercial interests since the 80's of the last century. At least this time
they haven't reassigned spectrum, but government support is no longer
provided for experimentation or emergency communication via satellites. 

New innovations now come from groups, not individuals because of the
combination of skills needed in engineering to develop a new innovation. It
is difficult to assemble a group of Amateur Radio Operators with the needed
skill sets to compete with commercial development and the development of
IC's to support new technology is economically beyond our reach. The days of
Edison and Bell with new inventions are gone. 

If we all hit the lottery, would we rush out and buy a launch for a HEO? 
Amateur Radio Operators represent 1/2 of 1 % of the US population, even the
politicians have no interest in us. 

Art,
KC6UQH



-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of John Spasojevich
Sent: Sunday, September 23, 2012 4:46 AM
To: TuZZio
Cc: AMSAT-BB
Subject: [amsat-bb] Re: dismantling satellite antennas

Ok..then I can do this.
No HEO so I wont pay my dues. I think AMSAT Italia should start right now
building a real satellite. I have been waiting and complaining for years.
Why wont they build it. Come on who cares about money just do ir so I can
stop writing daily about how schools are stealing our frequencies. When did
hams own frequencies? Nevermind. Beep sats and bleep sats and leo sats and
easy sats are all suck sats so I will not support any AMSAT

So how about I post that again and again day after day, week after week,
month after month. You can after all simply delete it when you see the
subject line.

John, AG9D
On Sep 23, 2012 1:36 AM, "TuZZio"  wrote:

> Il 22/09/2012 23.00, John Spasojevich ha scritto:
> > Then I guess we won't have to read any more complaining e-mail anymore
> >
> > John, AG9D
>
>
> Sorry to say but after the first reading, you can suppose the e-mail
> content from the subject, so you always have the "Canc" key; let people
> expose their free opinions until their are in topic.
>
> Good DX - 73 - I0NLK
> __**_
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[amsat-bb] FW: Re: dismantling satellite antennas

[Art McBride]

-Original Message-
From: Art McBride [mailto:kc6...@cox.net] 
Sent: Sunday, September 23, 2012 11:31 AM
To: 'John Spasojevich'; 'TuZZio'
Cc: 'AMSAT-BB'
Subject: RE: [amsat-bb] Re: dismantling satellite antennas

TO All,
This is just another thread documenting Pioneers, (the ones with the arrows
in their backs). Isn't this the same as 200 Meters and down that happened
almost 100 years ago? 
The experts at the time decided any communications on frequencies above
1,500 KHz would only carry a hundred miles or so and were useless for most
communications. Everything above 1,500 KHz was given to the Radio Amateurs
to experiment with. Once the experts were proven wrong, the government took
most of the spectrum from the Radio Amateurs, assigning it to commercial and
government interests. 

Amateur Radio Operators pioneered communications by satellite with the OSCAR
satellite series. Communications by Satellite has been led by Government and
Commercial interests since the 80's of the last century. At least this time
they haven't reassigned spectrum, but government support is no longer
provided for experimentation or emergency communication via satellites. 

New innovations now come from groups, not individuals because of the
combination of skills needed in engineering to develop a new innovation. It
is difficult to assemble a group of Amateur Radio Operators with the needed
skill sets to compete with commercial development and the development of
IC's to support new technology is economically beyond our reach. The days of
Edison and Bell with new inventions are gone. 

If we all hit the lottery, would we rush out and buy a launch for a HEO? 
Amateur Radio Operators represent 1/2 of 1 % of the US population, even the
politicians have no interest in us. 

Art,
KC6UQH



-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of John Spasojevich
Sent: Sunday, September 23, 2012 4:46 AM
To: TuZZio
Cc: AMSAT-BB
Subject: [amsat-bb] Re: dismantling satellite antennas

Ok..then I can do this.
No HEO so I wont pay my dues. I think AMSAT Italia should start right now
building a real satellite. I have been waiting and complaining for years.
Why wont they build it. Come on who cares about money just do ir so I can
stop writing daily about how schools are stealing our frequencies. When did
hams own frequencies? Nevermind. Beep sats and bleep sats and leo sats and
easy sats are all suck sats so I will not support any AMSAT

So how about I post that again and again day after day, week after week,
month after month. You can after all simply delete it when you see the
subject line.

John, AG9D
On Sep 23, 2012 1:36 AM, "TuZZio"  wrote:

> Il 22/09/2012 23.00, John Spasojevich ha scritto:
> > Then I guess we won't have to read any more complaining e-mail anymore
> >
> > John, AG9D
>
>
> Sorry to say but after the first reading, you can suppose the e-mail
> content from the subject, so you always have the "Canc" key; let people
> expose their free opinions until their are in topic.
>
> Good DX - 73 - I0NLK
> __**_
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> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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fo/amsat-bb>
>
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[amsat-bb] Re: fund raising for Fox

[Art McBride]

To All
This is a great way to reduce the posts to a quantity approaching "0" Could
AMSAT save money?
73,
Art, KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of K4FEG
Sent: Saturday, October 20, 2012 3:46 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] fund raising for Fox

I propose that AMSAT-NA start charging to post on the BB. My proposal 
goes something like this;

to be able to post on the AMSAT-BB, the individual posting must link a 
PayPal account or Valid Credit Card that AMSAT-NA can charge each time 
that they post on the BB.

The fee schedule would be as follows: Members; $1.00 per post, 
Non-members; $1.50 per post, a monthly charge for members of $60.00 per 
month for unlimited posts for that month and non-members a monthly 
charge $100.00 for the same unlimited monthly posting. Then there could 
be an annual charge to members of $500.00 for 1 year of unlimited 
postings or for non-members an annual charge of $750.00 for unlimited 
postings.

Finally we could sell Lifetime Posting Privileges for a one time fee of 
$5,000.00 for members and non-members a charge of $7,500.00.

These fee schedules are in line with many of the other organizations and 
just think of the funding that could be brought in for launching new 
satellites!!

Heck we could have HEO's, MEO's, LEO's and NEO's. There aren't enough 
engineering schools in the world to help us build the satellites. In the 
last month alone the fees would have funded putting a linear transponder 
on the MOON!

This is just one simple man's idea of how we could raise the money to 
get us some more Satellites in orbit!!
Heck, we are being charged for everything else why not tap into this 
valuable resource and raise some money for a good cause!

And you folks thought it would be tough to raise the money!

The simple ideas are always the best!

K4FEG
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[amsat-bb] Re: receiving 5.8 GHz

[Art McBride]

Norm,
You could start with the 5.1 GHz DRO in an old C Band LNB for the LO. Add an
LNA IC, and Mixer. Use the IF section in the C Band LNB to cover cable loss.

Art,
KC6UQH


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Lizeth Norman
Sent: Sunday, November 11, 2012 11:11 AM
To: <,amsat-bb@amsat.org>,
Subject: [amsat-bb] receiving 5.8 GHz

Hi all!
What schemes are available for someone who only has a funcube dongle?
It tops out at 1700 MHz. I am thinking hetrodyining using a brick and
a double balanced mixer. Block down converter is another option.
Any other options on the cheep side?
Norm n3ykf
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[amsat-bb] Re: receiving 5.8 GHz

[Art McBride]

Norm,
The LNB units are used on the C Band Satellite TV Receiving Dishes ( the
ones that are 8 to 15 ' in diameter). The DRO is a ceramic piece glued to
the PCB with a metal case around it and a adjustment screw. Some are fixed
in a metal can. The Mixer is used for 3.7 to 4.2 GHz Y may be able move it
up to 5.8 GHz. The LNA may be able to go there as well. The ARRL and THE
RSGB have several books on making things in this band. A lot of surplus
equipment at sites is being changed out for new, and you might find
something that can be tuned down in frequency from the 6 GHz band.
Mini-circuits has several Low Noise amplifiers and mixers that can be used.
Suggest you check out their web site. Try to fine some Amateur Radio
Microwave Activity in your area. Most of us will spend time helping others
to "get on the air" 

Good Luck,
Art, KC6UQH
http://www.minicircuits.com/homepage/homepage.html 
Good luck with the project
-Original Message-
From: Lizeth Norman [mailto:normanliz...@gmail.com] 
Sent: Sunday, November 11, 2012 10:04 PM
To: kc6...@cox.net
Cc: amsat-bb@amsat.org
Subject: Re: [amsat-bb] receiving 5.8 GHz

Art,
How do I recognize the Dielectric Resonance Oscillator? Where might I
get one of these units? Where, how and with what do I plumb the rf
with?
Suggestion on parts re the lna ic and I assume a mixer ic?
Wonder about the limit of dead bug construction at  GHz? What methods
might one use? I assume microstripline transmission lines..
No trips to AES, HRO or Skycraft here..
73 de Norm n3ykf

On Mon, Nov 12, 2012 at 12:46 AM, Art McBride  wrote:
> Norm,
> You could start with the 5.1 GHz DRO in an old C Band LNB for the LO. Add
an
> LNA IC, and Mixer. Use the IF section in the C Band LNB to cover cable
loss.
>
> Art,
> KC6UQH
>
>
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of Lizeth Norman
> Sent: Sunday, November 11, 2012 11:11 AM
> To: <,amsat-bb@amsat.org>,
> Subject: [amsat-bb] receiving 5.8 GHz
>
> Hi all!
> What schemes are available for someone who only has a funcube dongle?
> It tops out at 1700 MHz. I am thinking hetrodyining using a brick and
> a double balanced mixer. Block down converter is another option.
> Any other options on the cheep side?
> Norm n3ykf
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> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>

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[amsat-bb] Re: Microwave brick oscillators

[Art McBride]

Norm,
A few pF cap to the input side of the oscillator and a +10 dBm level signal
should work.
Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Lizeth Norman
Sent: Wednesday, November 28, 2012 6:02 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Microwave brick oscillators

Hi all!
Anyone have any experience with said units made by California
Microwave and Harris?
I do have a general idea how they work and would like to drive them
with a signal generator for lab use and testing for now.
Any ideas? I have pulled the crystal and know which pads drive. how do
I go from a signal generator to a crystal input?
Norm
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[amsat-bb] Re: QFHA for SO-50... polarization issue ???

[Art McBride]

Ing. Pavel,

There are a whole series of QFH antennas. 1/4,turn, 1/4 wavelength through 1
turn 1 Wavelength. 
Gain at the horizon is determined by the ratio of the axial length in
fractions of a wave length. The best performance I have obtained is a 1
wavelength per side, 1 turn, for good gain at the horizon with an axial
length of .65 wavelengths. You need the least gain at the Zenith as the
satellite is closest in range at that point.

The best reference I found is "Resonant Quadrifilar Helix Design" by C.C.
Kilgus, December 1970 Issue, of the Microwave Journal, Pgs 49-54.

73,
Art KC6UQH 






-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Ing. Pavel Milanes Costa
Sent: Saturday, February 16, 2013 8:22 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] QFHA for SO-50... polarization issue ???

This weekend I tested a Quadrifiliar Helicoidal Antenna for 70cm (LHCP)

I designed it by the online calculations of jcoppens on the internet...

It is a 1/2 turn and 1 lambda, about 5 meters of elevation with ~25 cm 
of RG-58U (a section of it is coiled to form a balum) and then ~15 
meters of A.H. LDF4-50A down to the shack directly to the radio, of 
course BNC to N adapter on the antenna and N to PL259 on the radio 
side... It's at mast top.

Results are good... In passes of over 20 degrees (almost the real 
horizon here) I have a good copy, until... TCA, in which I lost the 
signal completely...

TCA = Time of Closest Approach.

In northbound passes (I've not tested it in southbound) it work as I 
just said...

I have been reading and investigating this strange issue and I think it 
is due to polarization...

I had read that SO-50 is linear polarized on 2m AND 70cm with aprox 45 
degrees each other...

Then Linear to LHCP in the worst case is 3dB loss (half power) but 
consistent over the entire pass... or have SO-50 some 
circular/elliptical component in it's signals that renders useless the 
antenna after TCA? spin maybe?

There is any chapter of the book I missed or other variable(s) that I 
have not taking into account here?

Any comment, link or other kinds of help are welcomed..

73 de CO7WT.

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[amsat-bb] Re: Pendulum type elevation measurement

[Art McBride]

Panasonic and others offer a single or 3 axis accelerometer for Wi game
controllers. They provide outputs in analog, or digital. Sts and others also
have these with only digital outputs. The Single axis unit is 0.2 " square
by 0.1 " high runs on 5 VDC.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Gus
Sent: Sunday, February 24, 2013 1:15 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Pendulum type elevation measurement

On 02/24/2013 07:45 AM, Richard Ferryman wrote:
> For some time I have wanted a more accurate antenna elevation measurement
system.  Shaft encoders are beyond my budget.
Do mice still have balls?

Once upon a time every old mouse had two optical shaft-encoders built 
right in.  And mice can detect very tiny movements, so the 
sensors/encoders must be fairly precise.  Nowadays, most mice are 
optical or 'laser', but apparently, some mice are still available with 
balls.

So, who is going to take a mouse apart and use the bits to sense AZ/AL 
angles on an antenna array?

-- 
73, de Gus 8P6SM
Barbados, the easternmost isle.

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[amsat-bb] Re: Mount an Arrow on rotator with 2m vertical orhorizontal

[Art McBride]

RT,
It is done all the time. Each antenna is 50 Ohms A 1/4 wavelength or any
other odd multiple will transform impedance. Two 100 Ohm impedance ends are
combined make 50 Ohms. The impedance of the transforming line = 50 Ohms
times 100 Ohms = 5000 to the 1/2 power is 70.7 Ohms. So 75 OHM (closest to
70.7 Ohm line) is the line of choice for the power divider section. If you
put 1/2 the power into each antenna the gain for two antennas is 3 dB over
the total power into one antenna. The gain comes from the narrowing of the
pattern for a net gain of 3dB if the antennas are identical, pointed the
same direction, same polarization, and separated by at least 1/2 wave
length.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Douglas Phelps
Sent: Tuesday, April 16, 2013 11:31 AM
To: R.T.Liddy; amsat-bb@amsat.org
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical
orhorizontal

Any reason why, using identical coax lengths, you could not transform the 
impedance to 100 ohms and then use a T connector to sum both antenna signals
and 
achieve 50 ohms to the radio?  I know Transmit power will be 3 dB down at
either 
antenna but is there any reason it will not work?  Any antenna gurus out
there?





From: R.T.Liddy 
To: amsat-bb@amsat.org
Sent: Tue, April 16, 2013 11:46:35 AM
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical or
horizontal

For the Satellites, it completely doesn't matter. At any given moment,
you only have 1 chance in 90 that you will have matching polarization.
 
So, if you plan to use the antenna for other than Satellites, set your 
polarization
for that purpose (V for FM or H for SSB/CW).
 
My plan is to install 2 Elk antennas, one V and one H. Then, have a relay
that
I can switch between the two and choose the best downlink signal at any
given moment. This arrangement will also give me optimum flexibility for
terrestrial operation on 2 & 440. 
 
Now, where can I find a relay to do that function?
 
73/GL,    Bob K8BL


--- On Tue, 4/16/13, Lee Maisel  wrote:


From: Lee Maisel 
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical or
horizontal
To: "Don Hoover (WS4E)" 
Cc: amsat-bb@amsat.org
Date: Tuesday, April 16, 2013, 12:24 AM


Hi Don,

I have mine mounted with 2m elements horizontal, because that's how it 
seems I used it most when it was handheld.

Lee
W5LMM


Don Hoover (WS4E) wrote:
> Just wondering, should I mount my arrow with the 2m elements oriented
> vertical or horizontal?
>
> I am planning on putting it at 15deg and just using a az rotator.
>
> Does it even matter which way its oriented since the polarity of the sats
> are always changing?
>
> Maybe I should mount it like this: / instead.
>
> Just curious what some thought was the best way to go.
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>   


-- 


ΜΟΛΩΝ ΛΑΒΕ

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[amsat-bb] Re: Mount an Arrow on rotator with 2m verticalorhorizontal

[Art McBride]

Domenico,
There are two solutions to use coax to combine two 50 Ohm antennas. 70.7 Ohm
cable (50 to 100) [Two 50 ohm antennas transformed by two lines to 100 Ohms
each, in parallel = 50 Ohms] and your suggestion using 35.4 Ohm cable
section (25 to 50) = [Two 50 ohm antennas connected in parallel = 25 Ohms,
transformed to 50 Ohms] 

The interesting part is you do not save anything when using 75 Ohm coax as
1/4 wave sections (two in parallel =37.5 Ohms) VS two separate 75 ohm
sections one to each antenna.

Art, KC6UQH


-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of i8cvs
Sent: Wednesday, April 17, 2013 5:00 AM
To: Douglas Phelps; R.T.Liddy; Amsat - BBs
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m
verticalorhorizontal

Hi Douglas,

Using two identical 50 ohm coax lenght you can't  transform each 50 ohm
antenna impedance into 100 ohm but if you connect both 50 ohm coax cables
to a T connector than the resulting impedance at the common output of the T
connector will be 25 ohm i.e. two 50 ohm impedances in parallel and your
radio will see a VSWR of 50/25 = 2 and this is the reason it will not work !

BTW if you connect the above 25 ohm impedance to the input of a 1/4
electrical wavelenght long coax cable of 36 ohm impedance than at the output
of it you will get an impedance of  36^2 / 25 =  52 ohm toward the main feed
line with a good VSWR of about 1 in TX and RX

To build a 1/4 electrical wavelengt long of a transmission line of 36 ohm
impedance you can connect in parallel two 1/4 electrical wavelenght of
75 ohm coax cable like RG-59 or  RG-11 i.e. 34,13  centimeters or 13,38
inches long  for 145 MHz

BTW in this situation if both antennas are mounted in parallel one Vertical
and the other one Horizontal and if the elements are mounted on the same
plain with respect to the space than the resulting polarization of the
radiated field can be at 45 degrees like \ or at 135 degrees like /
depending at wich side of the dipoles the inner conductors of the 50 ohm
feed lines are connected.


73" de

i8CVS Domenico

- Original Message -
From: "Douglas Phelps" 
To: "R.T.Liddy" ; 
Sent: Tuesday, April 16, 2013 8:31 PM
Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical
orhorizontal

> Any reason why, using identical coax lengths, you could not transform the
> impedance to 100 ohms and then use a T connector to sum both antenna
> signals and achieve 50 ohms to the radio? I know Transmit power will be
> 3 dB down at either antenna but is there any reason it will not work?
> Any antenna gurus out there?
>

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[amsat-bb] Re: Mount an Arrow on rotator with 2m verticalorhorizontal

[Art McBride]

Domenico,
Loss for a 1/4 wave resonant line is small. RG 4121/2 5/8 and 3/4 inch 75
Ohm line for CATV is very low loss. If you build your own Coax the impedance
should be 35.4 Ohms for your preferred match.

73, Art   

-Original Message-
From: i8cvs [mailto:domenico.i8...@tin.it] 
Sent: Saturday, April 20, 2013 3:29 PM
To: kc6...@cox.net; 'Douglas Phelps'; 'R.T.Liddy'; 'Amsat - BBs'
Subject: Re: [amsat-bb] Re: Mount an Arrow on rotator with 2m
verticalorhorizontal

Hi Art, KC6UQH

Feeding a 50 ohm antenna with a odd numbar of 1/4 electrical wavelenght of
75 ohm coax cable you transform the 50 ohm antenna impedance into 100 ohm
and connecting two 100 ohm impedances in parallel you get again 50 ohm to
supply the system main fedline to TX and RX but using this solution the VSWR
into the 75 ohm coax cables is 75/50 = 1.5 and this VSWR represent losses
particularly at high frequencies from 435 MHz and up to 1296 MHz

On the other side feeding two 50 ohm antennas with the same lenghts of 50
ohm coax cables in parallel  you get a 25 ohm impedance to be transformed
again into 50 ohm using a matching line of  37.5 ohm 1/4 electrical
wavelenght long made with two pieces of coax cable 1/4 electrical wavelenght
long but in this solution the VSWR into both 50 ohm feeding lines will be
a good 1 to 1 and the losses are not very high so that this second solution
seems to be preferable.

The 37.5 ohm Zo impedance power divider can be professionally built in air
using two sections of round copper tubing 1/4 wavelenght long using the
following formula:

Zo = 138 log  (D/d)
  10

where D is the inside diameter of the outer tubing and d is the outside
diameter of the inner tubing.

In this solutions the RF losses are less than using two sections of 75 ohm
coax cables in parallel each 1/4 electrical wavelenght long so that this
round copper tubing power divider solution seems to be preferred and it
is that I currently use up to 1296 MHz


73" de

i8CVS Domenico

----- Original Message -
From: "Art McBride" 
To: "'i8cvs'" ; "'Douglas Phelps'"
; "'R.T.Liddy'" ; "'Amsat -
BBs'" 
Sent: Saturday, April 20, 2013 7:47 PM
Subject: RE: [amsat-bb] Re: Mount an Arrow on rotator with 2m
verticalorhorizontal


> Domenico,
> There are two solutions to use coax to combine two 50 Ohm antennas. 70.7
> Ohm cable (50 to 100) [Two 50 ohm antennas transformed by two lines to
> 100 Ohms each, in parallel = 50 Ohms] and your suggestion using 35.4 Ohm
> cable section (25 to 50) = [Two 50 ohm antennas connected in parallel
>  = 25 Ohms, transformed to 50 Ohms]
>
> The interesting part is you do not save anything when using 75 Ohm coax as
> 1/4 wave sections (two in parallel =37.5 Ohms) VS two separate 75 ohm
> sections one to each antenna.
>
> Art, KC6UQH
>
>
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of i8cvs
> Sent: Wednesday, April 17, 2013 5:00 AM
> To: Douglas Phelps; R.T.Liddy; Amsat - BBs
> Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m
> verticalorhorizontal
>
> Hi Douglas,
>
> Using two identical 50 ohm coax lenght you can't  transform each 50 ohm
> antenna impedance into 100 ohm but if you connect both 50 ohm coax cables
> to a T connector than the resulting impedance at the common output of the
> T connector will be 25 ohm i.e. two 50 ohm impedances in parallel and your
> radio will see a VSWR of 50/25 = 2 and this is the reason it will not
> work !
>
> BTW if you connect the above 25 ohm impedance to the input of a 1/4
> electrical wavelenght long coax cable of 36 ohm impedance than at the
> output of it you will get an impedance of  36^2 / 25 =  52 ohm toward
> the main feed line with a good VSWR of about 1 in TX and RX
>
> To build a 1/4 electrical wavelengt long of a transmission line of 36 ohm
> impedance you can connect in parallel two 1/4 electrical wavelenght of
> 75 ohm coax cable like RG-59 or  RG-11 i.e. 34,13  centimeters or 13,38
> inches long  for 145 MHz
>
> BTW in this situation if both antennas are mounted in parallel one
> Vertical and the other one Horizontal and if the elements are mounted on
> the same plain with respect to the space than the resulting polarization
> of the radiated field can be at 45 degrees like \ or at 135 degrees like /
> depending at wich side of the dipoles the inner conductors of the 50 ohm
> feed lines are connected.
>
>
> 73" de
>
> i8CVS Domenico
>
> - Original Message -
> From: "Douglas Phelps" 
> To: "R.T.Liddy" ; 
> Sent: Tuesday, April 16, 2013 8:31 PM
> Subject: [amsat-bb] Re: Mount an Arrow on rotator with 2m vertical
> orhorizontal
>
&

[amsat-bb] Re: J-Pole Antenna

[Art McBride]

Jeff,
You are correct, a J Pole is an end fed dipole on its side. Max gain at the
horizon and extinction at 90 degree elevation. The J section is for matching
and does not radiate. Gain = 2.1 dBi at the horizon.

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Jeff Moore
Sent: Sunday, May 12, 2013 10:48 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: J-Pole Antenna

I wouldn't recommend a J-pole for satellite work unless you expect to 
only work sats on the horizon.  The J-Pole antenna has a low take-off 
angle and almost NO radiation overhead,  an plain 1/4 wave ground plane 
antenna would work better for the sats.



J-poles are great terrestrial communications antennas, not so much for 
working overhead satellite passes.  An Eggbeater or quadrifiliar antenna 
would be a better choice.

7 3

Jeff Moore  --  KE7ACY

On 5/12/2013 8:00 AM, Werner, HB9BNK wrote
> Thank you all for your valuable hints and advices !
>
> I will now build such an antenna and then supply here the results.
>
> 73 Werner, HB9BNK

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[amsat-bb] Re: ISS HamTV Frequencies

[Art McBride]

Roger,
A SWAG, (Wild Guess) 1 degree per second at a Zenith of 90 degrees. Anything
less than 90 degrees will be slower with several minutes spent near the
horizon. You can use an orbital program to get exact numbers. With a wide
beam width antenna, the lag overhead may never require the antenna to move
with the object, as there will be time for the antenna system to catch up
after passing overhead. 
Art,
KC6UQH 

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Roger
Sent: Sunday, May 12, 2013 2:34 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: ISS HamTV Frequencies

Anybody off the top of their heads know how many degrees a second swing 
are (is?) required for direct aim at the ISS?  I know there are beam 
width tolerances, altitude variations and degree above horizon 
variations but I'm looking at Bob B's fixed antenna aiming of 15-20 
degrees above horizon to evaluate swinging a dish without torque eating 
up the drive train...

Roger
WA1KAT
On 5/12/2013 5:01 PM, M5AKA wrote:
> The AMSAT-UK page at http://amsat-uk.org/2013/05/12/hamtv-from-the-iss/
provides the links, they are:
>
> Facebook https://www.facebook.com/Hamtvproject
>
> More information at http://www.amsat.it/Amsat-Italia_HamTV_brochure.pdf
> and http://www.amsat.it/Amsat-Italia_HamTV.pdf
>
> The HamTV.pdf gives the link budget, looks like there's 7dB of
coax/connector losses to overcome between the ISS transmitter and the
antenna. That document indicates a 90cm dish should be sufficient.
>
> I believe that it's going up on ATV 4 which is currently slated for June
5.
>
> 73 Trevor M5AKA
>
>

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[amsat-bb] Re: Better/best operating system for SatPC32?

[Art McBride]

To ALL,
I have used Sat PC for several years on XP, and Vista. It crashes on me if I
disconnect the USB serial connection to the radio, otherwise it is a well
behaved program. How the bios handles the USB ports is computer specific and
could be the cause of the crashing. 

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Hector, CO6CBF
Sent: Saturday, May 18, 2013 9:56 AM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Better/best operating system for SatPC32?

Hello to all!

I have an old desktop PC dedicated to ham radio ( 1 GHz Pentium CPU, 256 MB
of RAM and Win XP). I have had SatPC32 running  24x7 since December and I
have never had a SatPC32 crash. 

73!

Hector, CO6CBF

-Mensaje original-
De: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] En nombre
de Jim Jerzycke
Enviado el: sábado, 18 de mayo de 2013 1:13
Para: amsat-bb@amsat.org
Asunto: [amsat-bb] Re: Better/best operating system for SatPC32?

Same here.

I've had it running on XP and Win 7 64-bit for WEEKS at a time and 
_never_ had a crash.

Jim  KQ6EA

On 05/18/2013 04:26 AM, George Henry wrote:
> Interesting.  I have NEVER had a SatPC32 crash, under XP or Win7, and 
> I have left it running continuously for several days at a time.
>
>
> George, KA3HSW
>
>
> - Original Message - From: "Lizeth Norman" 
> 
> To: "Philip Jenkins" 
> Cc: 
> Sent: Friday, May 17, 2013 10:55 PM
> Subject: [amsat-bb] Re: Better/best operating system for SatPC32?
>
>
>> None. Pick you poison. Satpc32 crashes using all operating systems. Good
>> for an hour or so. Then you get an OLE FEHER error. Tried this over all
>> operating systems (xp, win7, win8)
>> Grab a pc from the kerb and load up xp. cheap and simple.
>> As many problems as satpc32 has, it's far and away better than the
>> competition.
>>
>
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>

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[amsat-bb] Re: FO-29 wierdness during field day

[Art McBride]

Greg,
I had a hard time getting into the bird on that pass, figured it was
pointing angle or inversion layer. Next morning it was fine.

Art, KC6UQH (W6NWG for FD)

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Greg D
Sent: Tuesday, June 25, 2013 8:50 PM
To: Amsat BB
Subject: [amsat-bb] FO-29 wierdness during field day

Hi folks,

Now that the bustle of Field Day is over, an observation I want to pass 
on.  Did anyone else experience this?

On one of the Saturday night passes I noticed that FO-29 suddenly went 
kind of silent.  Not totally so, but enough that the QSO that I was 
desperately trying to complete was interrupted.  It was around 9:45 pm 
local PDT, if I recall.  Just finished with K6MMM, and was trying to get 
K6AA, I think.  (Note to self:  turn on the recorder next time!)

I didn't check for an eclipse, but that's my guess, though it was also 
about the time the bird went past TCA and all Doppler had broken loose.  
The bird sounded like 20 meters during the day, but with everyone's VFO 
on skids going in different directions.

Right towards the end of the pass I heard another station on, so I know 
the bird hadn't died.

Anybody hear that?

Greg  KO6TH

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[amsat-bb] Re: Lightning protection

[Art McBride]

Surface area counts ten for lightning protection. Down conductor braid ,
copper pipe or strap 2-3" wide has the most conductivity. Coiling Coax in a
3" diameter at the base of the tower and placing a separate ground strap on
the coax before the coil to strip off the lightning currents will off some
degree of protection.
For ideas and knowledge visit  http://www.protectiongroup.com/Home 

Art,
KC6UQH

-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of K5OE
Sent: Wednesday, October 16, 2013 11:45 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] Re: Lightning protection


K9STH wrote:
> Sorry, but NFPA NEC (National Electrical Code) definitely requires that
ALL 
> grounding electrodes MUST be connected together!  There are VERY good
reasons 
> for doing this...

Yeah, this is a requirement that has vexed designers of complex electrical
systems for years.
One solution, generally meeting this requirement, is to go ahead an utilize
separate ground rods
and tie the rods together with a (large) grounding cable--usually pvc
insulated cable for corrosion 
protection. In industrial installations these connections are often made so
they can be 
disconnected in the event of differential currents flowing and causing
problems with 
communication/signal systems.

Much like K8BL's recommendations, I too have used #10 AWG for the ground
from the rotor/mast
 to the ground rod, and hoped and prayed the lightning liked it (if ever
needed).  This is especially important
for a non-earthed installation like a tripod on a roof.  I have been
fortunate to never having to find out...

73,
Jerry, M0GOE
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