[Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[skipp025]

While you guys are on the subject of Motorola Mobile Radios made 
into repeaters... 

The factory frequency programming for the original repeater setup 
has a "blank" entry for the tx function in the receive radio and 
the same blank label in the rx frequency of the tx radio. Once 
someone changes the frequency slot it's not obvious how to restore 
a blank function into a replacement radio.  We've tried blank and 
zeros into the frequency slot but the software doesn't like something 
about the entry and defaults back to a number. 

Any clue how to enter in the "blank" or no-entry function in an 
unused motorola gm300/m120 mobile radio frequency choice? 

thanks for your answers... 
skipp  

> Mike Morris WA6ILQ <[EMAIL PROTECTED]> wrote:
>
> At 11:57 AM 03/20/07, you wrote:
> >You might want to try pin 14 instead of pin 8.
> >
> >I just got done interfacing a controller to a GM300 and couldn't
get pin 8
> >to work but pin 14 did.
> >
> >The RSS indicates both pin 8 and 14 are PL/DPL/CSQ detect but only
pin 14
> >seems to function properly.
> >
> >Randy
> 
> RSS will let you assign a function (like RSS) to multiple pins, but
> the radio won't work properly if you do that (the programmer that
> created that RSS forgot to check for that).  Before you upload a
> new codeplug to a radio you need to review the programming and
> make sure that you haven't multiply assigned a function.
> 
> And note that some pins pull down, and some pull up.
> Pin 4 pulls up, pin 8 and 14 both pull down.
> Some are output only, some are input only, and some are
> bidirectional.
> See this article "The Definitive Guide to the 16 pin MaxTrac and
> Radius Option Connector " at
> 
> 
> Mike
>

RE: [Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[N9WYS]

Skipp,

Not sure what the problem is you're experiencing there, but each time I
needed to blank out a frequency entry, I enter all zeros (000.0) and
when I hit he ENTER key it reads back as "Blank"... maybe you have something
else going on there.  ???

I know this didn't help your situation, but it sounds like you were doing
what you needed to.

Mark - N9WYS

-Original Message-
From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025


While you guys are on the subject of Motorola Mobile Radios made 
into repeaters... 

The factory frequency programming for the original repeater setup 
has a "blank" entry for the tx function in the receive radio and 
the same blank label in the rx frequency of the tx radio. Once 
someone changes the frequency slot it's not obvious how to restore 
a blank function into a replacement radio.  We've tried blank and 
zeros into the frequency slot but the software doesn't like something 
about the entry and defaults back to a number. 

Any clue how to enter in the "blank" or no-entry function in an 
unused motorola gm300/m120 mobile radio frequency choice? 

thanks for your answers... 
skipp  

RE: [Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[n3cdy]

type the word blank in the freq window
The radios were most likely programmed in the repeater mode of rss not radio 
mode.
This is a normal thing to occur
This is not even required unless you need to make absolutely sure that a 
receive radio never transmits ( ie into a preamp or multicoupler for instance )

-- Original message -- 
From: "N9WYS" <[EMAIL PROTECTED]> 

> Skipp, 
> 
> Not sure what the problem is you're experiencing there, but each time I 
> needed to blank out a frequency entry, I enter all zeros (000.0) and 
> when I hit he ENTER key it reads back as "Blank"... maybe you have something 
> else going on there. ??? 
> 
> I know this didn't help your situation, but it sounds like you were doing 
> what you needed to. 
> 
> Mark - N9WYS 
> 
> -Original Message- 
> From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025 
> 
> 
> While you guys are on the subject of Motorola Mobile Radios made 
> into repeaters... 
> 
> The factory frequency programming for the original repeater setup 
> has a "blank" entry for the tx function in the receive radio and 
> the same blank label in the rx frequency of the tx radio. Once 
> someone changes the frequency slot it's not obvious how to restore 
> a blank function into a replacement radio. We've tried blank and 
> zeros into the frequency slot but the software doesn't like something 
> about the entry and defaults back to a number. 
> 
> Any clue how to enter in the "blank" or no-entry function in an 
> unused motorola gm300/m120 mobile radio frequency choice? 
> 
> thanks for your answers... 
> skipp 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links 
> 
> 
> 

Re: [Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[Bob M.]

Just type BLANK and a bunch of spaces to fill the
field up. I know you can do this to the TX freq if you
want a receive-only channel, but I'm not sure you can
do it to the RX freq and still have a TX freq entered.
Try it and see. The MaxTrac RSS requires an RX freq
but the TX freq can be blank. Other radios may vary.

Bob M.
==
--- skipp025 <[EMAIL PROTECTED]> wrote:

> While you guys are on the subject of Motorola Mobile
> Radios made 
> into repeaters... 
> 
> The factory frequency programming for the original
> repeater setup 
> has a "blank" entry for the tx function in the
> receive radio and 
> the same blank label in the rx frequency of the tx
> radio. Once 
> someone changes the frequency slot it's not obvious
> how to restore 
> a blank function into a replacement radio.  We've
> tried blank and 
> zeros into the frequency slot but the software
> doesn't like something 
> about the entry and defaults back to a number. 
> 
> Any clue how to enter in the "blank" or no-entry
> function in an 
> unused motorola gm300/m120 mobile radio frequency
> choice? 
> 
> thanks for your answers... 
> skipp


 

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[Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[skipp025]

Well... 

Tried all that and the software wouldn't allow the blank entry. 
Per one of the other reply posts I only tried programming through 
the radio direct... not through the repeater software. Other 
than talking to the rick... what does the repeater software give
or get for me? 

Here's a cute service call cluster problem of the month.  
I actually sourced this fun out a few years back. 

The radius repeater was 100% original. The tx pa died and the 
previous service shop traded the radios around with minor 
re-programming. 

The tx radio was set to simplex (talk around) on the tx frequency. 

The co-channel user started trunking (without the proper license) 
on the same frequency. The tx radio heard the trunk beacon and would 
kerchunk itself into transmit (yeah... go figure). Every 10 seconds 
the repeater would kerchunk itself. Made the customer nuts for a  
week before I was called. 

The patch was to program a different frequency and dcs code into 
the tx radio receive frequency choice.  I know the original repeater 
tx radio had a programmed blank rx frequency... but I'm not able to 
restore that blank function rx programming. 

(sidebar note) Although I've never done it the Motorola Rick unit 
appears to be bidirectional if properly programmed. 

The additional patch was to let the co-channel user know his trunking 
operation was to "go away by the end of the week"... which it did for 
6 months before "she" tried it again. 

So the blank rx frequency option remains a mystery? 

skipp 


> "Bob M." <[EMAIL PROTECTED]> wrote:
> Just type BLANK and a bunch of spaces to fill the
> field up. I know you can do this to the TX freq if you
> want a receive-only channel, but I'm not sure you can
> do it to the RX freq and still have a TX freq entered.
> Try it and see. The MaxTrac RSS requires an RX freq
> but the TX freq can be blank. Other radios may vary.
> 
> Bob M.
> ==
> --- skipp025 <[EMAIL PROTECTED]> wrote:
> 
> > While you guys are on the subject of Motorola Mobile
> > Radios made 
> > into repeaters... 
> > 
> > The factory frequency programming for the original
> > repeater setup 
> > has a "blank" entry for the tx function in the
> > receive radio and 
> > the same blank label in the rx frequency of the tx
> > radio. Once 
> > someone changes the frequency slot it's not obvious
> > how to restore 
> > a blank function into a replacement radio.  We've
> > tried blank and 
> > zeros into the frequency slot but the software
> > doesn't like something 
> > about the entry and defaults back to a number. 
> > 
> > Any clue how to enter in the "blank" or no-entry
> > function in an 
> > unused motorola gm300/m120 mobile radio frequency
> > choice? 
> > 
> > thanks for your answers... 
> > skipp
> 
> 
>  
>

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[Repeater-Builder] Vertex VXR 7000 for sale

[Chris]

http://cgi.ebay.com/VERTEX-VXR-7000-VHF-130-174-pogrammable-
repeater_W0QQitemZ150103459155QQcategoryZ43010QQssPageNameZWDVWQQrdZ1QQc
mdZViewItem

hope this link works. item # 150103459155

Thanks

Chris

[Repeater-Builder] Repeater Controller

[Sam]

Do you have to use an external controller when putting 2 radios 
together for a repeater? I just want a simple RX & TX and have the TX 
radio PG with a 2min TOT. There are some cables on the internet that 
claim all you have to do is plug and play (MOTO Radiuu 16 pin). Do they 
really work?

Sam

Re: [Repeater-Builder] Vertex VXR 7000 for sale

[cruising7388]

 
In a message dated 3/21/2007 10:34:42 A.M. Pacific Daylight Time,  
[EMAIL PROTECTED] writes:

 
 
 
_http://cgi.ebay.http://cgi.http://cghttp://cgi.ehttp://cgi.e_ 
(http://cgi.ebay.com/VERTEX-VXR-7000-VHF-130-174-pogrammable-) 
repeater_W0QQitemZ1repeater_W0QQiterepeater_W0QQiterepeater_W0QQiterepea





 
Will it play below 146Mhz?



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Re: [Repeater-Builder] Repeater Controller

[Nate Duehr]

On 3/20/07, Sam <[EMAIL PROTECTED]> wrote:
> Do you have to use an external controller when putting 2 radios
> together for a repeater? I just want a simple RX & TX and have the TX
> radio PG with a 2min TOT. There are some cables on the internet that
> claim all you have to do is plug and play (MOTO Radiuu 16 pin). Do they
> really work?
>
> Sam

What service are you putting the repeater in?  Amateur?  Commercial?  GMRS?

Most services need some sort of transmitter ID to be legal.  If the
radios can't generate an ID, then the cross-over cable between two
rigs will "work" as a basic repeater, but could be illegal without
some form of ID.  Of course, we don't even know where you are, either
-- since this is an international list, so ... perhaps you're
somewhere the rules are different.

Also if this is your first foray into repeater building, you'll need
more than just the two radios and a cable!  If you're planning on
duplexing those radios into the same antenna you'll need at least a
duplexer... best to read up at http://www.repeater-builder.com for a
while on antenna systems.

This is a good starting point:
http://www.repeater-builder.com/rbtip/checklist.html

The majority of the cost (2x to 4x or more of the cost of the radios
themselves) of a good repeater setup at a fixed location isn't in the
radios at all, it's in the antenna, duplexer, isolator, bandpass
cavities (if needed), and feed line... if you're doing it "right".

Since you're talking about using mobile rigs, be aware that most
mobile rig transmitters will have to be de-rated in power by quite a
bit (and probably have fans added too) to survive the 100% duty-cycle
of typical repeater operation.

It all depends on what you're trying to accomplish... a couple of
mobile rigs can make a decent low-usage "backyard" low-power (and
usually low performance) repeater... but with some work can perform
okay.

Share some more details of what you're trying to accomplish, and folks
here are very helpful... most folks here can really say "been there,
done that - here's the best way to do what you're trying to
accomplish"... or at least give you two or three good options.

Nate WY0X

[Repeater-Builder] Trielectric Amp

[D Chubski]

Please anyone have any information on a Trielectric VHF Amp   Model A-2080 HBR 
?  
Thanks
   
  Dave
   

 
-
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.

Re: [Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[Charles Schmell]

Skipp - Make sure you know any "custom" programmng of
the radio in question (i.e. the 16 pin connector),
then switch back and forth between repeater and radio
modes in the RSS.  After you get back to the repeater
mode, only 1 option will be available for the TX and 1
for the Receiver.  At least that's how mine works. ;-)

Charles, KS3Z

--- skipp025 <[EMAIL PROTECTED]> wrote:

> While you guys are on the subject of Motorola Mobile
> Radios made 
> into repeaters... 
> 



 

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Re: [Repeater-Builder] Repeater Controller Recommendations

[no6b]

At 3/19/2007 18:52, you wrote:
>Question for the gurus: I am tuning up and donating an E.F. Johnson CR1100 
>repeater to the local Ham Club. They have asked me to install a talking, 
>chirping, beeping type repeater controller (which they have offered to 
>buy). I work with basic "repeater, one each" type stuff, so I have no idea 
>where to start. I welcome any opinions of a repeater controller that meets 
>the following somewhat carefully thought out criteria:
>
>1. Reasonably affordable. (a couple hundred bucks or so)

Here, essentially you get what you pay for.  I consider LinkComm & S-Com to 
be the top of the line in repeater controllers, but you'll pay a bit more, 
especially for the LinkComm RLC-Club, but it easily satisfies all the other 
requirements.

>
>2. It has to talk, beep and chirp.

Just about every controller beeps.  By "chirp" do you mean fancy sound 
effects?  Some of the cheaper controllers only have simple beeps & won't 
"chirp".

Bob NO6B

Re: [Repeater-Builder] 220 conversion

[James H Vernetti]

Has anyone tried to do a 220 mhz conversion on the Mitrek?

Re: [Repeater-Builder] Repeater Controller Recommendations

[Nate Duehr]

On 3/21/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:

> >2. It has to talk, beep and chirp.
>
> Just about every controller beeps.  By "chirp" do you mean fancy sound
> effects?  Some of the cheaper controllers only have simple beeps & won't
> "chirp".

Hahaha... I love the way you put that Bob.  It won't chirp!

The sound effects get old, real fast.  Even a simple dual-tone
ascending courtesy tone in a fast conversation can get annoying.  I
programmed one of our controllers on a repeater we recently worked on
this way.

I laughed out loud when one of our other techs who helped get it on
the air commented (after about a 40 minute drive home -- using the new
repeater and seeing how its coverage was working) -- "I feel like I've
been playing pong for half an hour!"

We'll probably be ... uh... removing that courtesy tone.

There is really only one good purpose for the sound effects... I can
tell which repeater I'm hearing, coming out of the scanner across the
room!

Nate WY0X

Re: [Repeater-Builder] OT: anyone a member of the MSF5000 group?

[Ken Arck]

At 01:54 PM 3/20/2007, you wrote:

>Didn't know there is or was a MSF group. Could someone give me some info

<--There's one on Yahoogroups (well actually 2 but one only has 5 
members so what's the point?)

I took delivery of a MSF5000 a couple of days ago and there is a bit 
of a learning curve (gimme a Micor and I'll recite everything about 
it in my sleep!).

I joined the groups several days ago but have not yet been approved 
by the owner... in the meantime, trying to figure out why the thing 
won't make power (I was lucky and received the complete set of 
manuals with the radio at least!)

Ken

--
President and CTO - Arcom Communications
Makers of the world famous RC210 Repeater Controller and accessories.
http://www.arcomcontrollers.com/
Coming soon - the most advanced repeater controller EVER.
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.net

Re: [Repeater-Builder] 220 conversion

[Glenn Little WB4UIV]

If your really meant what you asked, conversion to subaudiable frequencies, 
220 milliHertz, the conversion would be very difficult.

If you really meant 220 MHz, the conversion should be very similar to any 
other radio. Basically you have to convert the front end by reresonating 
the coils at the new frequency. Change the multipliers to get the proper 
injection frequency and level. The transmitter exciter can be changed by 
reworking to multipliers to get the desired frequency to a final. The final 
would have to be removed and replaced with either a home built PA or a PA 
module for the correct frequency.

The PA cannot be changed in frequency far enough to get to the new band as 
the transistors would be operating too far outside their frequency range.

The conversion is pretty straight forward and doable by someone with a good 
understanding of FM transmitters and superhetrodyne receivers.

I know of no cookbook method to do the conversion. One may exist, but I am 
not aware of it.

All the best on the conversion.

73
Glenn
WB4UIV



   At 06:19 PM 03/21/07, you wrote:
>Has anyone tried to do a 220 mhz conversion on the Mitrek?
>

[Repeater-Builder] Preamp and attenuator

[ldgelectronics]

Hi all, 

We've added a preamp to our local repeater and found that it had too 
much gain. It started picking up lots of garbage. Reducing the gain 
by about 6db seems to put it in a good operating place.

We also found that by putting the 6db attenuator on the input of the 
preamp (right after the band pass can), it's real easy to add in the 
system. If we mount it after the preamp, we'll need an adapter on 
each side of the preamp to make it all connect up. Obviously it would 
be best if we could put the attenuator after the pre and have no 
adapters, but it's not convenient. 

The question is how much trouble will be getting into by putting the 
6db attenuator on the input side of the preamp? Would it still be 
better to put it after the preamp even though it would add two 
adapters?

Thanks,

Dwayne Kincaid
WD8OYG

Re: [Repeater-Builder] Preamp and attenuator

[Ken Arck]

At 06:02 PM 3/21/2007, you wrote:




>The question is how much trouble will be getting into by putting the
>6db attenuator on the input side of the preamp? Would it still be
>better to put it after the preamp even though it would add two
>adapters?

<---You'd be much better placing the attentuator in the OUTPUT of the 
preamp (between it and the receiver). Remember that every dB of loss 
you place ahead of the preamp adds 1 dB of noise figure to the 
receiver. So you'd be adding 6 dB to your overall receiving system if 
you place the attentuator between the preamp and the duplexer

Ken
--
President and CTO - Arcom Communications
Makers of the world famous RC210 Repeater Controller and accessories.
http://www.arcomcontrollers.com/
Coming soon - the most advanced repeater controller EVER.
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.net

Re: [Repeater-Builder] Preamp and attenuator

[Steve Bosshard (NU5D)]

I have added a preamp (ARR GasFet) in front of older GE Pro receivers on UHF
and really made an improvement.  I am guessing you are using a single
antenna and a duplexer and the preamp is between the duplexer and receiver?

Are you using a band pass / band reject duplexer?  Some notch duplexers on
440 let signals either side of the notch pass through freely.  You might
change the coupling on the loops in the receive side of the duplexer to
increase loss (attenuation) and get steeper skirts.  Tell me a little about
the system, antenna, feedline, duplexer, jumpers, the repeater itself?

Thanks,  Steve NU5D

On 3/21/07, ldgelectronics <[EMAIL PROTECTED]> wrote:


Hi all,

We've added a preamp to our local repeater and found that it had too
much gain. It started picking up lots of garbage. Reducing the gain
by about 6db seems to put it in a good operating place.



Ham Radio Spoken Here.NU5D
Visit the Temple Ham Club Website
http://www.tarc.org
www.yahoogroups.com/group/Temple_arc
www.yahoogroups.com/group/60meter

[Repeater-Builder] Re: Preamp and attenuator

[ldgelectronics]

Steve,

It's on 2M, single Station Master antenna with about 400 feet of 7/8" 
feedline. The duplexer is a BP/BR followed by a band pass can, then 
the pre, then the radio side. All cables are RG-400.

The radio is GE Exec II. The sensitivity without the pre is about 
0.35 uV. The noise floor is pretty low, but the ARR pre was picking 
up a bunch of garbage without the attenuator.

Dwayne Kincaid
WD8OYG


>
> I have added a preamp (ARR GasFet) in front of older GE Pro 
receivers on UHF
> and really made an improvement.  I am guessing you are using a 
single
> antenna and a duplexer and the preamp is between the duplexer and 
receiver?
> 
> Are you using a band pass / band reject duplexer?  Some notch 
duplexers on
> 440 let signals either side of the notch pass through freely.  You 
might
> change the coupling on the loops in the receive side of the 
duplexer to
> increase loss (attenuation) and get steeper skirts.  Tell me a 
little about
> the system, antenna, feedline, duplexer, jumpers, the repeater 
itself?
> 
> Thanks,  Steve NU5D
> 
> On 3/21/07, ldgelectronics <[EMAIL PROTECTED]> wrote:
> >
> > Hi all,
> >
> > We've added a preamp to our local repeater and found that it had 
too
> > much gain. It started picking up lots of garbage. Reducing the 
gain
> > by about 6db seems to put it in a good operating place.
> >
> 
> Ham Radio Spoken Here.NU5D
> Visit the Temple Ham Club Website
> http://www.tarc.org
> www.yahoogroups.com/group/Temple_arc
> www.yahoogroups.com/group/60meter
>

Re: [Repeater-Builder] Re: Moto GM300's Used With External Controller - Blank Frequency Entry

[Milt]

Skipp,

IIRC the GM300 will not allow a blank RX only a blank TX.  Usual way to fix 
the issue you described is just what you did, different freq and a wierd PL 
or DPL, also set the RX to LOCAL.  The RICK was a general do-it-all-for -you 
controller and can be set up as Uni-directional or Bidirectional.  It can 
also support a local controller or with some creativity a third radio as a 
link.

Milt
N3LTQ

- Original Message - 
From: "skipp025" <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, March 21, 2007 1:08 PM
Subject: [Repeater-Builder] Re: Moto GM300's Used With External Controller - 
Blank Frequency Entry


> Well...
>
> Tried all that and the software wouldn't allow the blank entry.
> Per one of the other reply posts I only tried programming through
> the radio direct... not through the repeater software. Other
> than talking to the rick... what does the repeater software give
> or get for me?
>
> Here's a cute service call cluster problem of the month.
> I actually sourced this fun out a few years back.
>
> The radius repeater was 100% original. The tx pa died and the
> previous service shop traded the radios around with minor
> re-programming.
>
> The tx radio was set to simplex (talk around) on the tx frequency.
>
> The co-channel user started trunking (without the proper license)
> on the same frequency. The tx radio heard the trunk beacon and would
> kerchunk itself into transmit (yeah... go figure). Every 10 seconds
> the repeater would kerchunk itself. Made the customer nuts for a
> week before I was called.
>
> The patch was to program a different frequency and dcs code into
> the tx radio receive frequency choice.  I know the original repeater
> tx radio had a programmed blank rx frequency... but I'm not able to
> restore that blank function rx programming.
>
> (sidebar note) Although I've never done it the Motorola Rick unit
> appears to be bidirectional if properly programmed.
>
> The additional patch was to let the co-channel user know his trunking
> operation was to "go away by the end of the week"... which it did for
> 6 months before "she" tried it again.
>
> So the blank rx frequency option remains a mystery?
>
> skipp
>
>
>> "Bob M." <[EMAIL PROTECTED]> wrote:
>> Just type BLANK and a bunch of spaces to fill the
>> field up. I know you can do this to the TX freq if you
>> want a receive-only channel, but I'm not sure you can
>> do it to the RX freq and still have a TX freq entered.
>> Try it and see. The MaxTrac RSS requires an RX freq
>> but the TX freq can be blank. Other radios may vary.
>>
>> Bob M.
>> ==
>> --- skipp025 <[EMAIL PROTECTED]> wrote:
>>
>> > While you guys are on the subject of Motorola Mobile
>> > Radios made
>> > into repeaters...
>> >
>> > The factory frequency programming for the original
>> > repeater setup
>> > has a "blank" entry for the tx function in the
>> > receive radio and
>> > the same blank label in the rx frequency of the tx
>> > radio. Once
>> > someone changes the frequency slot it's not obvious
>> > how to restore
>> > a blank function into a replacement radio.  We've
>> > tried blank and
>> > zeros into the frequency slot but the software
>> > doesn't like something
>> > about the entry and defaults back to a number.
>> >
>> > Any clue how to enter in the "blank" or no-entry
>> > function in an
>> > unused motorola gm300/m120 mobile radio frequency
>> > choice?
>> >
>> > thanks for your answers...
>> > skipp
>>
>>
>>
>>
> 
>> Sucker-punch spam with award-winning protection.
>> Try the free Yahoo! Mail Beta.
>> http://advision.webevents.yahoo.com/mailbeta/features_spam.html
>>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>

[Repeater-Builder] Re: Preamp and attenuator

[ldgelectronics]

Ken, thanks for the input.

So if I were to adjust the band pass can to have 3 db loss (it's at 
0.5 db right now) and steeper skirts, it would raise the noise figure 
about 2.5 db as well.

That seemed like a good trick at first, but still raises the noise 
figure.

Obviously lower noise figure is better, but is there some place where 
the trade off would be worth it? Maybe I'm not asking the question 
properly.

> 
> >The question is how much trouble will be getting into by putting 
the
> >6db attenuator on the input side of the preamp? Would it still be
> >better to put it after the preamp even though it would add two
> >adapters?
> 
> <---You'd be much better placing the attentuator in the OUTPUT of 
the 
> preamp (between it and the receiver). Remember that every dB of 
loss 
> you place ahead of the preamp adds 1 dB of noise figure to the 
> receiver. So you'd be adding 6 dB to your overall receiving system 
if 
> you place the attentuator between the preamp and the duplexer
> 
> Ken
> 
--
> President and CTO - Arcom Communications
> Makers of the world famous RC210 Repeater Controller and 
accessories.
> http://www.arcomcontrollers.com/
> Coming soon - the most advanced repeater controller EVER.
> Authorized Dealers for Kenwood and Telewave and
> we offer complete repeater packages!
> AH6LE/R - IRLP Node 3000
> http://www.irlp.net
>

Re: [Repeater-Builder] Re: Preamp and attenuator

[Ken Arck]

At 06:31 PM 3/21/2007, you wrote:

>Ken, thanks for the input.
>
>So if I were to adjust the band pass can to have 3 db loss (it's at
>0.5 db right now) and steeper skirts, it would raise the noise figure
>about 2.5 db as well.

That seemed like a good trick at first, but still raises the noise figure.
>
>Obviously lower noise figure is better, but is there some place where
>the trade off would be worth it? Maybe I'm not asking the question
>properly.

<--What make and model preamp are you running? Or at least, what is 
it spec'd for gain-wise?

Ken
--
President and CTO - Arcom Communications
Makers of the world famous RC210 Repeater Controller and accessories.
http://www.arcomcontrollers.com/
Coming soon - the most advanced repeater controller EVER.
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.net

Re: [Repeater-Builder] Re: Preamp and attenuator

[Steve Bosshard (NU5D)]

Sounds like a nice setup Dwayne.  I would make sure the duplexer is tuned
properly, maybe run an isolated TEE test just to be sure everything is OK.

Next I would rotate the coupling loops to increase insertion loss and make
the skirts steeper.  What Wacom taught me to do was to take a cavity, hook
up a sweeper with a TEE fitting between the Gen and Rec and set a reference
signal, then hook the TEE to one side of the cavity and rotate the loop for
about 8 db of notch at the pass freq, then move the TEE to the other side of
the cavity, and again rotate the second loop for the same degree of notch -
this makes the cavity symetrical so that both the input and output loops
have the same degree of coupling.  Next measure the loss through the
cavity.  Play with the degree of coupling and insertion loss till you get
what you are looking for.

Best 73, Steve NU5D


RG-400 or LMR 400?  sb


On 3/21/07, ldgelectronics <[EMAIL PROTECTED]> wrote:


Steve,

It's on 2M, single Station Master antenna with about 400 feet of 7/8"
feedline. The duplexer is a BP/BR followed by a band pass can, then
the pre, then the radio side. All cables are RG-400.

The radio is GE Exec II. The sensitivity without the pre is about
0.35 uV. The noise floor is pretty low, but the ARR pre was picking
up a bunch of garbage without the attenuator.

Dwayne Kincaid
WD8OYG




--
Ham Radio Spoken Here.NU5D
Visit the Temple Ham Club Website
http://www.tarc.org
www.yahoogroups.com/group/Temple_arc
www.yahoogroups.com/group/60meter

Re: [Repeater-Builder] Re: Preamp and attenuator

[Steve Bosshard (NU5D)]

I did mean coupling loops on the single band pass cavity and not the
duplexer.  SB


On 3/21/07, Steve Bosshard (NU5D) <[EMAIL PROTECTED]> wrote:


Sounds like a nice setup Dwayne.  I would make sure the duplexer is tuned
properly, maybe run an isolated TEE test just to be sure everything is OK.

N



--
Ham Radio Spoken Here.NU5D
Visit the Temple Ham Club Website
http://www.tarc.org
www.yahoogroups.com/group/Temple_arc
www.yahoogroups.com/group/60meter

[Repeater-Builder] Re: Preamp and attenuator

[Laryn Lohman]

--- In Repeater-Builder@yahoogroups.com, "ldgelectronics"
<[EMAIL PROTECTED]> wrote:
>
> Hi all, 
> 
> We've added a preamp to our local repeater and found that it had too 
> much gain. It started picking up lots of garbage. 

Elaborate on the term .  Intermod?  Users from distant
repeaters?  If intermod, it may be produced in the preamp or receiver
if not protected enough with selectivity ahead of the preamp.  If
users, you've achieved your goal of increasing the sensitivity of your
system.  Adding attenuation ahead of the preamp very effectively
removes much of the sensitivity you've gained with the preamp.  I'd
deal with that kind of garbage in other ways.

Reducing the gain 
> by about 6db seems to put it in a good operating place.
> 
> We also found that by putting the 6db attenuator on the input of the 
> preamp (right after the band pass can), it's real easy to add in the 
> system. If we mount it after the preamp, we'll need an adapter on 
> each side of the preamp to make it all connect up. Obviously it would 
> be best if we could put the attenuator after the pre and have no 
> adapters, but it's not convenient. 

Attenuation placed ahead of the preamp is nowhere near the same as
placing it behind.  Placing it behind reduces the gain of the preamp
while retaining the noise figure of the preamp.  In my experiments on
2m with an ARR preamp and Motrac receiver, up to about 10db of
attenuation after the preamp did not reduce system sensitivity.

> 
> The question is how much trouble will be getting into by putting the 
> 6db attenuator on the input side of the preamp? Would it still be 
> better to put it after the preamp even though it would add two 
> adapters?

In most cases yes.  I've read about cases on this group where
attenuation ahead of the preamp is the proper thing to do, but the
reasons escape me.  

Laryn K8TVZ


> 
> Thanks,
> 
> Dwayne Kincaid
> WD8OYG
>

Re: [Repeater-Builder] 220 conversion

[Mike Morris WA6ILQ]

At 04:19 PM 03/21/07, you wrote:
>Has anyone tried to do a 220 mhz conversion on the Mitrek?

I've been thinking about it for a while...
There are two approaches - take a UHF radio and put a
modified high band front end in, and bypass a doubler, or
take a high band radio and move it up.

The mods that move the entire radio multipliers from
12mhz x12mult=144mhz to 18.5mhz x 12mult=222Mhz
just are not practical... the 18mhz rocks are not stable in
the channel elements, plus they don't modulate well.
The conversion of the final multipler from a x2 to a x3 is
much cleaner and simpler.

I'd take a high band radio and change both the receiver
local oscillator multiplier and the transmitter exciter multipler
so that instead of doubling from 74mhz to 148mhz you triple
from 74 to 222MHz.  You might need to change out the last
multipler transistor to something with a little bit higher Ft.

The front end work has pretty much been done by Scott
and Kevin on the Micor, and the same techniques can
be used both there and in the helicals between the
exciter and the PA deck.

The PA is hopeless as the VHF striplines won't play
at 220, but a radio with a dead PA is ideal for conversion...
just strip the PA down to the heat sink and put down a
220mhz power brick.  Or if you have enough drive use
a Wilkinson combiner backwards to split the drive to
two PAs and use a second one to combine them back
to a single feedline.  Double the pleasure and all that...

The transmitter deviation will need to be cranked down as
the multipler is higher... times 18 vs times 12.
If it comes to the worst case a 3:2 resistive divider can be
inserted between the audio stages and the channel element.

Receive audio is unchanged.

The high band Mitrek is essentially an updated single-board
version of the old Motran with a better front end, and a
stripline PA vs an LC PA...
the techniques developed by the 220Mhz guys in Chicago
(CFMC ??? I forget) 30 years ago for the Motran still work
fine (except for the PA mod).

Mike WA6ILQ

[Repeater-Builder] Re: Preamp and attenuator

[ldgelectronics]

Darn, I meant to put that in before. I have severaldifferent units. I'd 
like to use an ARR with 15 db gain (1 db NF), but we also have a couple 
of older Lunar with about 15 db gain and some stock GE units with about 
10 db. The Angle is on the list to try.

One of the systems we just took out the ARR and put the GE back in at 
the lower gain (higher NF) until we figure out this attenuator thing.

Dwayne Kincaid
WD8OYG

> <--What make and model preamp are you running? Or at least, what is 
> it spec'd for gain-wise?
> 
> 

Re: [Repeater-Builder] Re: Preamp and attenuator

[Ken Arck]

At 08:21 PM 3/21/2007, you wrote:


>Darn, I meant to put that in before. I have severaldifferent units. I'd
>like to use an ARR with 15 db gain (1 db NF), but we also have a couple
>of older Lunar with about 15 db gain and some stock GE units with about
>10 db. The Angle is on the list to try.

<--I heartily recommend AngleLinear products. You simply can't go wrong!

Ken
--
President and CTO - Arcom Communications
Makers of the world famous RC210 Repeater Controller and accessories.
http://www.arcomcontrollers.com/
Coming soon - the most advanced repeater controller EVER.
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.net

[Repeater-Builder] Re: Preamp and attenuator

[ldgelectronics]

Steve,

That's good info on tuning the BP can. I will put that info in the 
file.

I'm pretty sure the duplexer is tuned properly. The four can BP/BR is 
a Sinclair 202. It's got right at 1.5 db loss on each side with about 
83 db of rejection on each.

There area also two Sinclair BP/BR cans. One on the TX and one on the 
RX. The loss is set for 0.5 db on each.

The interconnect cable is RG-400, no LMR.

Dwayne Kincaid
WD8OYG


>
> Sounds like a nice setup Dwayne.  I would make sure the duplexer is 
tuned
> properly, maybe run an isolated TEE test just to be sure everything 
is OK.
> 
> Next I would rotate the coupling loops to increase insertion loss 
and make
> the skirts steeper.  What Wacom taught me to do was to take a 
cavity, hook
> up a sweeper with a TEE fitting between the Gen and Rec and set a 
reference
> signal, then hook the TEE to one side of the cavity and rotate the 
loop for
> about 8 db of notch at the pass freq, then move the TEE to the 
other side of
> the cavity, and again rotate the second loop for the same degree of 
notch -
> this makes the cavity symetrical so that both the input and output 
loops
> have the same degree of coupling.  Next measure the loss through the
> cavity.  Play with the degree of coupling and insertion loss till 
you get
> what you are looking for.
> 
> Best 73, Steve NU5D
> 
> 
> RG-400 or LMR 400?  sb
> 
> 
> On 3/21/07, ldgelectronics <[EMAIL PROTECTED]> wrote:
> >
> > Steve,
> >
> > It's on 2M, single Station Master antenna with about 400 feet of 
7/8"
> > feedline. The duplexer is a BP/BR followed by a band pass can, 
then
> > the pre, then the radio side. All cables are RG-400.
> >
> > The radio is GE Exec II. The sensitivity without the pre is about
> > 0.35 uV. The noise floor is pretty low, but the ARR pre was 
picking
> > up a bunch of garbage without the attenuator.
> >
> > Dwayne Kincaid
> > WD8OYG
> >
> >
> 
> -- 
> Ham Radio Spoken Here.NU5D
> Visit the Temple Ham Club Website
> http://www.tarc.org
> www.yahoogroups.com/group/Temple_arc
> www.yahoogroups.com/group/60meter
>

[Repeater-Builder] Comtegra DTMF

[Com/Rad Inc]

21 Mar 2007

We have a Comtegra remote application and desire to add DTMF decode.
This is a software download of some type. 
Need to avoid adding an aftermarket decoder if possible

Ed Folta
Com/Rad Inc.

[Repeater-Builder] Re: Preamp and attenuator

[ldgelectronics]

The "garbage" was pops, static, crackling on weak user signals. There 
was also some intermod that would drop the receiver on all but the 
strongest users.

The distant users were able to go farther, but the garbage noise made 
it more difficult to actually use.

Dwayne Kincaid
WD8OYG

> Elaborate on the term .  Intermod?  Users from distant
> repeaters?  

[Repeater-Builder] LMR feedline revisited and revised!

[Jay Urish]

Did anybody see the ad for the 'new' LMR series feedline in this months 
league journal?(QST)

They are going to an aluminum braid instead of the tinned copper. Its 
supposed to make it lighter and cheaper.

Any opinions on whether this will make it more suitable for duplex work?
-- 
Jay Urish W5GM
ARRL Life MemberDenton County ARRL VEC
N5ERS VP/Trustee

Monitoring 444.850 PL-88.5

RE: [Repeater-Builder] Re: Preamp and attenuator

[Gary Schafer]

Hook your signal generator up to your system at the antenna port and measure
receiver sensitivity with and without the preamp. Then with the preamp in
circuit start adding attenuation between the preamp and the receiver. When
you just start to loose sensitivity stop adding attenuation. That should
give you near optimum sensitivity without excessive gain. Too much gain in
the preamp overloads the receiver mixer and front end amp if it has one. 

For every db of gain you add in front of the receiver you reduce the IM
performance of the receiver.

You only want enough preamp gain to overcome the noise figure of the
receiver. Although the noise figure of the receiver and preamp are
cumulative the preamp is the biggest contributor in setting system noise
figure. In other words putting a hot preamp on a very hot receiver will give
you a better overall noise figure than putting that same preamp on a poor
receiver but the difference will not be great.

You may not be able to realize the full benefit of the preamp if you have
excessive IM. You may have to add more attenuation to where it further
reduces receiver sensitivity. When you get down to the point that the
sensitivity is the same as it was without the preamp, then throw out the
preamp. But you may be able to find a happy medium where the preamp does
help some without destroying your IM performance.

If you still have excess IM problems you can add attenuation ahead of the
preamp by raising the insertion loss of the loops on your band pass filter
as others have suggested. By raising the insertion loss on the loops it does
the same thing as adding an attenuator ahead of the preamp but with the
added benefit of steeper skirts on the band pass filter.

By the way don't worry about adding adaptors between the preamp and
receiver. After all you are looking to add attenuators anyway. But adaptors
really make no measurable difference in attenuation at vhf or uhf. They may
give a slight impedance mismatch but you probably don't have anything that
will measure the small amount of loss from them.

73
Gary  K4FMX


> -Original Message-
> From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
> [EMAIL PROTECTED] On Behalf Of ldgelectronics
> Sent: Wednesday, March 21, 2007 9:32 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Re: Preamp and attenuator
> 
> Ken, thanks for the input.
> 
> So if I were to adjust the band pass can to have 3 db loss (it's at
> 0.5 db right now) and steeper skirts, it would raise the noise figure
> about 2.5 db as well.
> 
> That seemed like a good trick at first, but still raises the noise
> figure.
> 
> Obviously lower noise figure is better, but is there some place where
> the trade off would be worth it? Maybe I'm not asking the question
> properly.
> 
> >
> > >The question is how much trouble will be getting into by putting
> the
> > >6db attenuator on the input side of the preamp? Would it still be
> > >better to put it after the preamp even though it would add two
> > >adapters?
> >
> > <---You'd be much better placing the attentuator in the OUTPUT of
> the
> > preamp (between it and the receiver). Remember that every dB of
> loss
> > you place ahead of the preamp adds 1 dB of noise figure to the
> > receiver. So you'd be adding 6 dB to your overall receiving system
> if
> > you place the attentuator between the preamp and the duplexer
> >
> > Ken
> > 
> --
> > President and CTO - Arcom Communications
> > Makers of the world famous RC210 Repeater Controller and
> accessories.
> > http://www.arcomcontrollers.com/
> > Coming soon - the most advanced repeater controller EVER.
> > Authorized Dealers for Kenwood and Telewave and
> > we offer complete repeater packages!
> > AH6LE/R - IRLP Node 3000
> > http://www.irlp.net
> >
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 

RE: [Repeater-Builder] LMR feedline revisited and revised!

[Eric Lemmon]

Jay,

You are referring to the blurb on the lower right corner of page 69 of the
April, 2007, issue of QST.

The notion of a "lite" version of any coaxial cable raises a red flag in my
mind.  Emotions aside, my take is that it will be LESS suitable for duplex
work, and will enjoy the same low esteem earned by the "new" Belden 9913F
cable.  Inasmuch as the antenna and its feedline are usually the MOST
critical components in any radio station, and usually are the MOST difficult
to install, maintain, or troubleshoot (usually when freezing temperatures
and high winds prevail), it hardly seems likely that anyone would even
consider saving a few bucks to buy "lite" coaxial cable- but they are out
there!

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jay Urish
Sent: Wednesday, March 21, 2007 9:01 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] LMR feedline revisited and revised!

Did anybody see the ad for the 'new' LMR series feedline in this months 
league journal?(QST)

They are going to an aluminum braid instead of the tinned copper. Its 
supposed to make it lighter and cheaper.

Any opinions on whether this will make it more suitable for duplex work?
-- 
Jay Urish W5GM
ARRL Life Member Denton County ARRL VEC
N5ERS VP/Trustee

[Repeater-Builder] Re: Preamp and attenuator

[skipp025]

> > We've added a preamp to our local repeater and found that it 
> > had too much gain. It started picking up lots of garbage. 

I would ask if there is such a thing as "too much gain" but there 
can be. Normally I would would not expect gain to be a problem in a 
well designed - constructed system. But I was not able to get one 
of Angle's 40 dB gain jobs to work without a whip and a chair. So 
yes I guess there can be cases of too much preamp gain. But probably 
not with a typical good repeater receiver preamplifier in many/most 
common repeater applications. You have a fly in your soup... is 
it gain fly or something else?  
 
> Elaborate on the term .  Intermod?  Users from distant
> repeaters?  If intermod, it may be produced in the preamp or 
> receiver if not protected enough with selectivity ahead of the 
> preamp.  

A big time Amen... people forget the short distance a preamp travels 
to become a mixer. We really should know more about his receiver 
protection as requested below. 

> Adding attenuation ahead of the preamp very effectively
> removes much of the sensitivity you've gained with the preamp.  
> I'd deal with that kind of garbage in other ways.

A much better idea... why point a finger at the preamp when the 
problem might actually be part of a bigger system picture. 

> > Reducing the gain by about 6db seems to put it in a good 
> > operating place. We also found that by putting the 6db 
> > attenuator on the input of the preamp (right after the band 
> > pass can), it's real easy to add in the system. If we mount 
> > it after the preamp, we'll need an adapter on each side of 
> > the preamp to make it all connect up. Obviously it would 
> > be best if we could put the attenuator after the pre and have 
> > no adapters, but it's not convenient. 

> Attenuation placed ahead of the preamp is nowhere near the same 
> as placing it behind.  Placing it behind reduces the gain of the 
> preamp while retaining the noise figure of the preamp.  In my 
> experiments on 2m with an ARR preamp and Motrac receiver, up to 
> about 10db of attenuation after the preamp did not reduce system 
> sensitivity.

Some of us are wondering why you need an attenuator in any position?  
It's not an automatic requirement... 

> > The question is how much trouble will be getting into by putting 
> > the 6db attenuator on the input side of the preamp? Would it 
> > still be better to put it after the preamp even though it would 
> > add two adapters?

Forget the attenuators and the adapters and give us more information 
about the system.  What type of preamp, bandpass cavity, duplexer 
and receiver are you using?  Gasfet?, Phempt?, Bipolar? Nuvistor? 
(I said Nuvistor for some of you older radio guys)

> In most cases yes.  I've read about cases on this group where
> attenuation ahead of the preamp is the proper thing to do, but the
> reasons escape me.  

Depends on the equipment but the first answer I would say is for
reasons of stability. Some of us actually use more than one series 
preamp with specific value attenuators in specialized antenna 
combiner systems... very "hot" high performance receiver antenna 
systems. 

cheers, 
s. 

[Repeater-Builder] Register now for 2007 IRLP/VoIP conference

[Nevada Amateur Radio Repeaters, Inc.]

The date for the 2007 VoIP Conference is Friday April 13 - Sunday April 15,
2007  just before the National Association of Broadcasters (NAB) conference,
also in Las Vegas.  The conference highlights IRLP but all VoIP systems
owners and users are invited to present papers, or just attend.

 

http://www.narri.org/Annual_IRLP_Conference.html

 

http://www.narri.org/IRLP_Conference_Details.html 

 

http://www.narri.org/IRLP_Conference_Registration_Form.html 

 

For more information contact Kent W7AOR at w7aor at narri dot org