RE: [AMRadio] BC-610 terminating impedance

[John Coleman ARS WA5BXO]

I may have missed something here amongst all the messages and I
really am not too familiar with the BC610 but I thought it had variable
loading with an adjustable 3-4 turn link.  If so, it should be able to
load into a fairly wide range of loads.  On my variable link rig I can
go down to about 10 ohms load by pulling the link out to maintain the
proper plate current, but with the link in all the way the proper
loading (indicated by plate current)is reached when the load is about
100 ohms.  Of course if the load is 10 ohms and the link pulled out for
proper plate current I need to be very careful not to pour the coals on
with the plate voltage or the link will over heat.  I have been able to
load to proper plate current with a 300 ohm load but I had to parallel
tune my link instead of series tune.  

As for SWR bridges, I think many people get the properties of
loads and sources mixed up.  All the SWR meters I have measure the match
between the line and the load and they don't give a hoot about the
source as long as there is no reactance in the line from the source.

SWR is defined as the ratio of transmission line to load.  Not
source to line.  

Given the scenario of a XMITER (say 100 watts) that has been
adjusted to match a 50 ohm dummy load on a 1/2 wave length of coax cable
and the SWR meter is at the load end of the cable.  If the load
resistance is increase to 100 ohms the SWR meter should show 2:1 and the
transmitter should have 1/2 output RF current, Hence 1/2 power.  If the
transmitters load is adjusted to compensate and bring the RF current and
plate current back up to normal it will be putting out 100 watts again.
But the SWR meter should still show 2:1.  The 100 ohm load will get all
must a hot as the 50 ohm load and in many cases you will not be able to
tell the difference in temperature.  If there is a slight difference it
will be caused by the slight increase in loss of the transmission line
due to the SWR of 2:1.  This is generally not of any consequence on 80
or 40 meters.  For the most part the load is still getting the 100 watts
even though it is 100 ohms instead of 50 ohms.

By the same token many SWR meters that are not at the load end
of the cable may not give the correct reading and especially if the
source is not a resistive output as most transmitters are not unless
they or pre adjusted with the desired load attached with a very short
cable.

The reason I said a 1/2 wave length of coax in the above
scenario, is because that with a 1/2 wave length (must take in effect of
slow velocity of coax) the value of load resistance is reflected at the
source.  At a 1/4 wave length is either multiplied of divided by the SWR
depending on whether the load is greater that the line characteristic
impedance or less than it.

Of course if the SWR is 1:1 then it doesn't matter how long the
line is or where you measure it.

The only need I have found for an SWR meter is, as an indicator
of the tuning of an antenna tuner for random length wire or balanced
line doublets.  Also many solid state radios have no tuning built in and
can only work right into a 50 ohm non reactive load.  In this case a PI
type tuner for coax fed antennas is very useful for fine tuning to the
proper load. (Basically, it takes the place of an internal tune and load
procedure, as older tube type radios had.)  The SWR meter is a good
indicator to use when it is placed at the input of the tuner and the
transmitter has been pre-tuned into a 50 ohm dummy load.  When the
antenna tuner is adjusted correctly, as indicated by the SWR meter, the
transmitter will be loaded just as it was with the dummy load and will
not have to be retuned.

SEE http://www.qsl.net/wa5bxo/swr/swr.htm

John,
WA5BXO



  
  

Re: [AMRadio] BC-610 terminating impedance

[Barrie Smith]

This has been an interesting thread, and I learned some things about the 
HT4-B/BC-610.


Relative to the polarization issue:  I read a rather long article quite a 
few years ago about a ham who was also an electronics professor at a 
university in Italy, I believe.


He set up two separate antennas, one vertical and one horizontal, feeding 
two separate receivers, and fed the IF output of one of the RX to the 
vertical plates of an O'scope, and the other RX to the horizontal plates.


With each receiver tuned to the same frequency, he could watch the relative 
signal strength of the vertical or horizontal polorization on the 'scope.


While I don't remember all the details, I do remember that when skip was 
involved the polorization of the incoming signal varied considerably, and 
the most likely polorization was a combination of both, which was a 45 
degree angle trace on the scope.


I think that cross-polorization only really matters on line-of-sight 
signals.


73, Barrie, W7ALW 



---
[This E-mail scanned for viruses by Declude EVA]

[AMRadio] SX101MARK3A

[david oneill]

HAVE FOR SALE A NICE WORKING GOOD LOOKING SX101 $225.00 PHOTOS ON REQUEST.

[AMRadio] Re: [Johnson] Amp advice

[John Lawson]

On Sat, 29 Oct 2005, Ed Tanton wrote:

Well... just my 2 cents, mind you... but it's bad enough using a linear for 
AM, considering the efficiency yielding only a little more signal than 
talking louder would accomplish... but a **SINGLE** 3-500Z combined with all 
that INefficiency? Complete waste of time and 3-500Z after (what will be) 
short-lived 3-500Z.




   Thanx Ed!



  Well:  Nummer One - It's only a Hobby. As in: to have fun with.

 Nummer Two - I got the AL-80 and Tuner pretty cheap. (SK estate)

 Nummer Three - I have a Ranger and a Valiant. The Ranger needs a 
couple of minor 'tweaks'; the Valiant has a few things that need fixin', 
and that equals time and money, thus I'll go with what I have, and work on 
Improvements later..


 Nummer Four - I'm actively looking for a Thunderbolt - none on 
the hook right now.


 Nummer Five - No one's actually *answered* the questions I have 
about 'waking up' the amp. (Yet, at any rate.) There has been some very 
pertinent and helpful advice, however - much appreciated.


 Nummer Six - see Nummer One. Don't curse the QRP - light a 
Filament!




Cheers

John   KB6SCO

Re: [AMRadio] BC-610 terminating impedance

[Jim Wilhite]

- Original Message - 
From: "Jim Candela" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "Discussion of AM Radio" 


Sent: Saturday, October 29, 2005 9:39 AM
Subject: Re: [AMRadio] BC-610 terminating impedance



Bob Wrote:
>
Now about that polarization issue you mentioned. I had
long in depth conversations with the late Ozona Bob,
W5PYT concerning this. What I recall is that when
receiving skip at HF, the polarization is constantly
changing, and the QSB you experience is in part due to
that. The other part is vector addition & subtraction
from picking up the same signal from different paths,
phase, and time delay. Bob figured that if he
transmitted circular polarization this would in effect
reduce QSB at the receiving end. I recall he had huge
diagonally mounted turnstile dipoles mounted nearly a
football field high (the top). At my QTH (Austin), he
was always on the S-meter peg, and NO QSB. That was a
distance of 250 miles, day and night.

I myself would be hesitant to put up a 80 meter
vertical because my buddies close in within Texas
would have trouble hearing me if they were beyond
groundwave distance, and before the first hop
distance.

Now how does KC9VF get out so well? Doesn't he have a
vertical dipole on 80 meters?

For skip reception, it seems that the transmitted
polarization, isn't a big issue, but more of a angle
of radiation issue.

Regards,
Jim Candela
WD5KJKO



Jim did you ever visit Bob, W5PYT at his shack?  I was there once a few 
years before he died.  I missed him but went out to where the transmitter 
was located in an old abandoned microwave transmitter site.  I would guess 
the tower to be about 300 ft. high and so many wires hanging from it a bird 
could not fly within 1/4 mile of it.


I didn't see a turnstile, but I would have challenged anyone to spot any of 
antenna in that grouping.  As for Marv., his antenna is a 193 ft.tower 
installed like a broadcast antenna.  He operated it for a while without 
radials until he could find time to install them.  The only difference in 
his signal then and now with the radials, is he is a bit louder at my QTH 
but not a lot.  I always hear his signal and if I loose him, I loose signals 
from stations equidistant that use dipoles.


I have a friend that says the antennas are the only black art left.  You 
calculate what it will do then install it.  Then you set about making it 
work.  I tend to agree with that logic.  One thing I am convinced about is 
put up a dipole rather than a Vee.  The mismatch is minimal but you get the 
voltage points up in the air.  In that case the ends do not tend to induct 
into the ground or surrounding structures, natural or manmade.


I know many people will disagree and use some magic antenna modeling 
calculator to prove me wrong, but I get consistently better signals reports 
using a dipole at 40 ft. than with a Vee at 55 ft.  In Marv's case he has 
more tower (wire) in the air therefore more capture/radiation area.  And he 
also has a good ground system.


At the lower frequencies of BCB you see a lot of stations that you hear day 
and night and the low angle radiation tends to extend the coverage at night, 
but there are still lobes that will cover closer in.  I had a vertical in 
Wyoming and was able to work the same stations at nigh that I did in the 
daytime.  I only had 4 quarter wave radials under it.  My signal was not as 
strong at night, but I still had "local" coverage with a good enough signal.


I know I am opening a can of worms since so much of this theory depends on 
your installation so let the guessing begin.


73  Jim
W5JO 

Re: [AMRadio] BC-610 terminating impedance

[k0ng]

Well said Jim !! There is only one antenna that works well at any given
moment and that is the one that does (work well) if you are lucky.

73, Charlie, K0NG.

Quoting Jim Candela <[EMAIL PROTECTED]>:

> Bob Wrote:
>
> >Of course I have not pursued a whip installation.  It
> >would seem to be a useless endeavor as the 160, 80,
> 40, >and 20 meter bands are "normally" of horizontal
> >polarization.  I see no logic in operating in cross
> >polarization, and making communications more
> difficult >than necessary.
>
> Hi Bob, I enjoyed your BC-610 thread. It makes me wish
> I had obtained one back when I had several chances. I
> recall a story from Dave, W6PSS when he was moving his
> three 610's in a trailer, and was involved in a bad
> traffic accident. He was OK, but the 610's did not
> fare well.
>
> Now about that polarization issue you mentioned. I had
> long in depth conversations with the late Ozona Bob,
> W5PYT concerning this. What I recall is that when
> receiving skip at HF, the polarization is constantly
> changing, and the QSB you experience is in part due to
> that. The other part is vector addition & subtraction
> from picking up the same signal from different paths,
> phase, and time delay. Bob figured that if he
> transmitted circular polarization this would in effect
> reduce QSB at the receiving end. I recall he had huge
> diagonally mounted turnstile dipoles mounted nearly a
> football field high (the top). At my QTH (Austin), he
> was always on the S-meter peg, and NO QSB. That was a
> distance of 250 miles, day and night.
>
> I myself would be hesitant to put up a 80 meter
> vertical because my buddies close in within Texas
> would have trouble hearing me if they were beyond
> groundwave distance, and before the first hop
> distance.
>
> Now how does KC9VF get out so well? Doesn't he have a
> vertical dipole on 80 meters?
>
> For skip reception, it seems that the transmitted
> polarization, isn't a big issue, but more of a angle
> of radiation issue.
>
> Regards,
> Jim Candela
> WD5KJKO
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
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> AM List Admin: Brian Sherrod/w5ami
>





This message was sent using IMP, the Internet Messaging Program.

Re: [AMRadio] Amp advice

[Mike Dorworth,K4XM]

Good point. The Ranger modulation transformer is 7500 to 3500 ohms and rated
for about 15 watts audio level. It was used at 32.5 watts for voice service
which is A-OK. As example the famous ART-13 transformer is rated at 50 watts
and we all know that they will do plenty more for VOICE service. The mod
transformer that has to pass the magnetizing final current requires very
careful spacing of the core gap. Broadcast service gets by this at the
higher powers by using a choke and capacitor to shunt feed the final. This
allows more BASS. They have to do 50 cycles ( Hertz for new guys).
.
>
> Remember, the less load drawn through the secondary of the stock Ranger
> modulation transformer, the better the audio is going to sound, stock
> out of the Ranger.
> The reason being, there's less plate current being drawn through the
> secondary of the modulation transformer, and therefore less chance of
> core-saturation, cause the hysteresis curve of the transformer not to be
> as linear as possible.
>
> ---
> 73 = Best Regards,
> -Geoff/W5OMR

Re: [AMRadio] Amp advice

[W5OMR/Geoff]

W5OMR/Geoff wrote:

The reason being, there's less plate current being drawn through the 
secondary of the modulation transformer, and therefore less chance of 
core-saturation, cause the hysteresis curve of the transformer not to 
be as linear as possible.




should read "causING the hysteresis curve of..." 


darned blonde fingers.  ;-)


---
73 = Best Regards,
-Geoff/W5OMR 

Re: [AMRadio] Amp advice

[W5OMR/Geoff]

Mike Dorworth,K4XM wrote:


It seems we're back to where we were. In theory the maximum carrier is
limited to half the tube dissipation. i.e 250 watts. The power supply is
good for about half that amount. This means the Ranger can put out at MAX
around 12  to13 watts. The carrier about 125 watts, the pep output about 500
watts. Your ability to buy power transformers and tubes may vary.. Hope this
helps.. Mike



Sounds good. 

Were it me, and that was the way I had to go, I think I'd stiffen up the 
power supply as best as possible.
Depending on the capabilities of the plate transformer, maybe stick 
another 3-500Z in parallel to the one that exists, and run the amp to 
300w of carrier, and let the positive peaks fill the 1.5kW pep 
envelope.  It might even take a bit more drive from the Ranger, so 
instead of an attenuator pad for RF on the amp input, maybe vary the DC 
voltage on the plate, or the screen voltage of the 6146 in the Ranger, 
adjusting the level to whatever is required.


Remember, the less load drawn through the secondary of the stock Ranger 
modulation transformer, the better the audio is going to sound, stock 
out of the Ranger.
The reason being, there's less plate current being drawn through the 
secondary of the modulation transformer, and therefore less chance of 
core-saturation, cause the hysteresis curve of the transformer not to be 
as linear as possible.


---
73 = Best Regards,
-Geoff/W5OMR

Re: [AMRadio] Amp advice

[Mike Dorworth,K4XM]

It seems we're back to where we were. In theory the maximum carrier is
limited to half the tube dissipation. i.e 250 watts. The power supply is
good for about half that amount. This means the Ranger can put out at MAX
around 12  to13 watts. The carrier about 125 watts, the pep output about 500
watts. Your ability to buy power transformers and tubes may vary.. Hope this
helps.. Mike
- Original Message - 
From: "John Lawson" <[EMAIL PROTECTED]>
To: 
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, October 29, 2005 4:25 PM
Subject: [AMRadio] Amp advice


>
>   I have recently acquired (from the estate of a Silent Key) an Ameritron
> AL-80 (not A, B, or C) and the Ameritorn ATR-15 tuner.
>
>   These were used together for years, then sat for an unknown length of
> time before being disconnected and moved.   I am the second owner.
>
>The tuner exhibits constructional saliency with masonry defecatoria,
and
> appears to be in nearly factory-new shape internally - the case is dusty a
> bit, but also very nice.
>
>The amp, [while modified slightly with some extra ventilation holes and
> a large power-transistor type heatsink bolted to the case adjacent to
> where the 3-500Z lives], seems to be visually in good shape - it seems to
> have had one of it's power-equalizing resistors (on the rectifier/filter
> board) replaced. It's wired for a 220 mains supply, which I will also
> operate it on.
>
>   Initially I'll be driving the AL-80 with a Ranger, thence into the
> ATR-15, 450-ohm ladderline to the 450' fence-top loop guarding my back
> yard.  I've completed the re-route of that ladder-line following previous
> suggestions and admonishments, BTW - and thanks to y'all for that!!
>
>
>I've not owned a higher-power amp before, so aside from the usual
> caveats concerning powering up 'older' gear for the first time - I was
> wondering if there are any Ameritron-specific "gotchas" to be aware of -
> and certainly if there is any wisdom, anecdotes, or cautions concerning
> this amp - especially as I'm going to use it on AM fone - I'd be
> appreciative of the experiences you've (collectively) had.
>
>
>Cheers
>
> John KB6SCO
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
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> AM List Admin: Brian Sherrod/w5ami
>

[AMRadio] Amp advice

[John Lawson]

 I have recently acquired (from the estate of a Silent Key) an Ameritron 
AL-80 (not A, B, or C) and the Ameritorn ATR-15 tuner.


 These were used together for years, then sat for an unknown length of 
time before being disconnected and moved.   I am the second owner.


  The tuner exhibits constructional saliency with masonry defecatoria, and 
appears to be in nearly factory-new shape internally - the case is dusty a 
bit, but also very nice.


  The amp, [while modified slightly with some extra ventilation holes and 
a large power-transistor type heatsink bolted to the case adjacent to 
where the 3-500Z lives], seems to be visually in good shape - it seems to 
have had one of it's power-equalizing resistors (on the rectifier/filter 
board) replaced. It's wired for a 220 mains supply, which I will also 
operate it on.


 Initially I'll be driving the AL-80 with a Ranger, thence into the 
ATR-15, 450-ohm ladderline to the 450' fence-top loop guarding my back 
yard.  I've completed the re-route of that ladder-line following previous 
suggestions and admonishments, BTW - and thanks to y'all for that!!



  I've not owned a higher-power amp before, so aside from the usual 
caveats concerning powering up 'older' gear for the first time - I was 
wondering if there are any Ameritron-specific "gotchas" to be aware of - 
and certainly if there is any wisdom, anecdotes, or cautions concerning 
this amp - especially as I'm going to use it on AM fone - I'd be 
appreciative of the experiences you've (collectively) had.



  Cheers

John KB6SCO

[AMRadio] Re: [T-368_BC-610] BC-610 terminating impedance

[Rbethman]

Robert & others,

Both, my BC-610(I) AND my T-213 have had the porcelain insulators 
replaced with an SO-239.  Upon loading into the ME-165G, my SWR into the 
50 ohm dummy load "barely" flickers the needle off the stop on 
reflected, it at all.


Both of the transmitters came with movable link coils.  The only coils I 
have that DON'T have movable links are the 160 meter ones.


In testing the ME-165G with an antenna impedance test bridge shows it 
indeed to be 50 ohm impedance.


With all this in consideration, I must therefore conclude that the 
output of BOTH transmitters to be 50 ohm output.


The 3 terminal input insulators on the side of the BC-939 are 
misleading.  Internal inspection reveals one terminal to be for a ground 
connection.  The other two are wired internally with 50 ohm coaxial 
cable.  The reason for the space between those two terminals is the 
plate voltage issue.  In the CW position, the plate voltage is 2500VDC.  
In AM, the plate voltage is 2000VDC.  were it NOT for the spacing of the 
terminals, there would be constant issues with possible arcing - 
ESPECIALLY while you are tuning the BC-939 to the tuning tables/cards.


There are also TWO different models of the BC-939.  There is an A model 
and a B model.  I haven't noted any obvious differences, but there 
apparently are some somewhere.


Bob N0DGN

[EMAIL PROTECTED] wrote:


Bob & Group,

As originally issued, the BC-610-A through -E had plug-in final 
amplifier tank coils with fixed links.  Conversion kits were issued 
during the war that included the rotary link tank coils.  Those issued 
for SCR-299 also included tuning units above 8 MC (originally the 
upper limit of the SCR-299-A through -D).  Some of the kits, including 
one for SCR-399-A and SCR-499-A (BC-610-E), came with a doublet 
(dipole) antenna which eventually (post-war) became AN/GRA-4.  The 
1.0-2.0 MC kits also included a doublet.


The BC-939-A originally came with a 3-terminal feed-through insulator 
on the side for input.  It and the earlier BC-729 were connected to 
the BC-610-(*) with a short length of shielded cable.


The ME-165/G was built for the T-368/GRT, which was set up for coaxial 
cable from the git-go.


But anyway, the output impedance of a BC-610 depends on the number of 
turns in the output coupling link on the plug-in final amplifier plate 
tank coil, not whether it has the original ceramic feed-through posts 
or not.


In a message dated 10/28/2005 12:53:43 PM Central Daylight Time, 
[EMAIL PROTECTED] writes:



There is NO question that the output of the BC-610 series, my first one
happens to be an (I) model, is indeed 50 ohms impedance.  It is
unfortunate that some hams make the ASSUMPTION that since it has
porcelain insulators for the output, that it is a balanced output of
OTHER than 50 ohms.

I cannot stress the importance of obtaining the manual, carefully
studying it, and pay close attention to the details.  The ME-165G is
unquestionably a 50 ohm input SWR/Wattmeter/dummy load.  It comes with
"N" connectors for input and output.




--
Bob - NØDGN
  
+--+

|  \\"""//\\"""//  |
|   (@ @)   Bob Bethman - NØDGN(@ @)   |
+---oOOo-(_)-oOOo--oOOo-(_)-oOOo---+
| NØDGN AMRadio Manassas, VA|REAL Tube Radio and AM|
+---+--+
|   Manassas Radio - Home of Homemade Kielbasa & Pirogi|
+---+--+
| Bob Bethman\\\|/// " The absence of a danger |
| rbethman(at)comcast.net   \\ ~ ~ //  signal does *NOT* mean  |
|   (/ @ @ /)  that everything is OK " |
+-oOOo-(_)-oOOo+
|   |
| 1 BC-61ØI w/BC-614I,1 T-213/GRC-26 w/BC614I,1 '51 Collins R-390A |
|  SP-600/NR Type 159, Heath DX-60, Apache, Mohawk, SX-101, HT-32A |
+---.oooO---Oooo.---.oooO---Oooo.--+
|   () ()   () ()  |
|\  (   )  / \  (   )  /   |
| \ _) ( _/   \ _) ( _/|
+--+
|   Amateur Astronomer - Celestron Nexstar 8   |
| 12" f5 Dob coming soon!  Being built |
|  Meade ETX-6Ø|
|   38 Deg 46'48.62"' N - 77 Deg 28'26.89" W   |
+--+
|   Opinions expressed are that of my own and do not necessarily   |
| coincide with or represent those of ANYONE else  |
+--.oooO

Re: [AMRadio] FS: Several Microphones

[Rbethman]

You only fixed one of them - Keep trying.

Bob - N0DGN

[EMAIL PROTECTED] wrote:


Try again now Geoff:

http://www.af4k.com/imag/ham/CB45.jpg

On 29 Oct 2005 at 10:23, W5OMR/Geoff wrote:

 


[EMAIL PROTECTED] wrote:

   


FOR SALE - MICROPHONES FOR HAM RADIO ETC.

Picture: http://www.af4k.com/imag/ham/CB45.jpg


 


error 404: File not found

   

http://af4k.com/turner_sr785_datasheet.jpg 

 


error 404: File not found

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--
Bob - NØDGN
  
+--+

|  \\"""//\\"""//  |
|   (@ @)   Bob Bethman - NØDGN(@ @)   |
+---oOOo-(_)-oOOo--oOOo-(_)-oOOo---+
| NØDGN AMRadio Manassas, VA|REAL Tube Radio and AM|
+---+--+
|   Manassas Radio - Home of Homemade Kielbasa & Pirogi|
+---+--+
| Bob Bethman\\\|/// " The absence of a danger |
| rbethman(at)comcast.net   \\ ~ ~ //  signal does *NOT* mean  |
|   (/ @ @ /)  that everything is OK " |
+-oOOo-(_)-oOOo+
|   |
| 1 BC-61ØI w/BC-614I,1 T-213/GRC-26 w/BC614I,1 '51 Collins R-390A |
|  SP-600/NR Type 159, Heath DX-60, Apache, Mohawk, SX-101, HT-32A |
+---.oooO---Oooo.---.oooO---Oooo.--+
|   () ()   () ()  |
|\  (   )  / \  (   )  /   |
| \ _) ( _/   \ _) ( _/|
+--+
|   Amateur Astronomer - Celestron Nexstar 8   |
| 12" f5 Dob coming soon!  Being built |
|  Meade ETX-6Ø|
|   38 Deg 46'48.62"' N - 77 Deg 28'26.89" W   |
+--+
|   Opinions expressed are that of my own and do not necessarily   |
| coincide with or represent those of ANYONE else  |
+--.oooO---Oooo.---+
|  () ()   |
|   \  (   )  /|
|\ _) ( _/ |
|ALL E-mail received and sent scanned by AVG & Norton System Works |
+--+


   

Re: [AMRadio] FS: Several Microphones

[bcarling]

Try again now Geoff:

http://www.af4k.com/imag/ham/CB45.jpg

On 29 Oct 2005 at 10:23, W5OMR/Geoff wrote:

> [EMAIL PROTECTED] wrote:
> 
> >FOR SALE - MICROPHONES FOR HAM RADIO ETC.
> >
> >Picture: http://www.af4k.com/imag/ham/CB45.jpg
> >  
> >
> 
> error 404: File not found
> 
> >http://af4k.com/turner_sr785_datasheet.jpg 
> >
> 
> error 404: File not found
> 
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
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Re: [AMRadio] FS: Several Microphones

[bcarling]

You were too quick - I uploaded it about 10 seconds after your e-
mail!

Try again now Geoff!

http://www.af4k.com/imag/ham/CB45.jpg

On 29 Oct 2005 at 10:23, W5OMR/Geoff wrote:

> [EMAIL PROTECTED] wrote:
> 
> >FOR SALE - MICROPHONES FOR HAM RADIO ETC.
> >
> >Picture: http://www.af4k.com/imag/ham/CB45.jpg
> >  
> >
> 
> error 404: File not found
> 
> >http://af4k.com/turner_sr785_datasheet.jpg 
> >
> 
> error 404: File not found
> 
> __
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Re: [AMRadio] FS: Several Microphones

[W5OMR/Geoff]

[EMAIL PROTECTED] wrote:


FOR SALE - MICROPHONES FOR HAM RADIO ETC.

Picture: http://www.af4k.com/imag/ham/CB45.jpg
 



error 404: File not found

http://af4k.com/turner_sr785_datasheet.jpg 



error 404: File not found

[AMRadio] FS: Several Microphones

[bcarling]

FOR SALE - MICROPHONES FOR HAM RADIO ETC.

First is a brand new dual impedance hand microphone:
Shure Hand Microphone CB45. NEW IN BOX. 

This is a great noise cancelling microphone - 
ideal for high noise environments such as 
mobile in a car or truck. It has the famous Shure 
"CONTROLLED MAGNETIC cartridge." 
Dual Impedance - LOW or HIGH. 
Works great with any radio. Brand new and never 
has been used.  Available for $35.00 plus 
shipping.
Picture: http://www.af4k.com/imag/ham/CB45.jpg

TURNER DESK MICROPHONE. 
Model "Plus Three" - Excellent condition. Has 
a nice coil cord all in good shape with 4-pin 
plug. 
Was used with a Heath HW-101 Transceiver. Works 
fine with many other rigs too. 
Will sell for $35.00 plus shipping. 
Picture: http://www.af4k.com/imag/ham/TURNER3.JPG

Turner SR785 Gooseneck microphone, NEW IN THE BOX. 
Just like at K Mart! Has PTT bar and cable 
attached. 
This is a rugged, low impedance communications 
microphone, 150 ohms. 
Designed for crystal clear voice communications by 
radio or P.A. 
If you know Turner mics, you know that they all 
sound great. 
Satin-chrome finish with rugged, durable metal 
construction that 
will give you many years of good performance in 
any communications 
environment. Comes new in the box with data sheet.

QTY 2 left - New in box for $19.00 each plus 
shipping

Picture: 
http://af4k.com/imag/ham/turner_gooseneck.jpg
http://af4k.com/turner_sr785_datasheet.jpg 

Re: [AMRadio] BC-610 terminating impedance

[Jim Candela]

Bob Wrote:

>Of course I have not pursued a whip installation.  It
>would seem to be a useless endeavor as the 160, 80,
40, >and 20 meter bands are "normally" of horizontal
>polarization.  I see no logic in operating in cross 
>polarization, and making communications more
difficult >than necessary.

Hi Bob, I enjoyed your BC-610 thread. It makes me wish
I had obtained one back when I had several chances. I
recall a story from Dave, W6PSS when he was moving his
three 610's in a trailer, and was involved in a bad
traffic accident. He was OK, but the 610's did not
fare well.

Now about that polarization issue you mentioned. I had
long in depth conversations with the late Ozona Bob,
W5PYT concerning this. What I recall is that when
receiving skip at HF, the polarization is constantly
changing, and the QSB you experience is in part due to
that. The other part is vector addition & subtraction
from picking up the same signal from different paths,
phase, and time delay. Bob figured that if he
transmitted circular polarization this would in effect
reduce QSB at the receiving end. I recall he had huge
diagonally mounted turnstile dipoles mounted nearly a
football field high (the top). At my QTH (Austin), he
was always on the S-meter peg, and NO QSB. That was a
distance of 250 miles, day and night.

I myself would be hesitant to put up a 80 meter
vertical because my buddies close in within Texas
would have trouble hearing me if they were beyond
groundwave distance, and before the first hop
distance.

Now how does KC9VF get out so well? Doesn't he have a
vertical dipole on 80 meters? 

For skip reception, it seems that the transmitted
polarization, isn't a big issue, but more of a angle
of radiation issue.

Regards,
Jim Candela
WD5KJKO