[Milsurplus] ATD Transmitter

[Meir-WF2U]

Hi Rian,

 

I used the 100 pF series cap because it works well with my BC-1306 on the
same frequencies; I’m getting around 22 W out of it on CW.

I don’t use a series cap with the GRC-9. The “Doublet” position tunes into
50 ohms just fine and the power output is 20W.

The 100 pF series cap also works with the BC-223 to run it into 50 ohms.
Without it I can only get around 2 W into the 50 ohm system. With it, I get
20W out, which would be what I’d expect from the output tube.

The ATD may have somewhat different tuning characteristics, as the aircraft
antennas used with it are longer than the whips the “field” radios were
designed for.

More experimentation is needed with the matching. I expect with proper
matching I should be getting at least 60 W out of it.

 

73, Meir WF2U

Landrum, SC 

 

   _____  

From: Rian Robison [mailto:krrobison at earthlink.net] 
Sent: Wednesday, October 01, 2008 12:40 AM
To: w7qho; Meir-WF2U; Milsurplus at mailman.qth.net
Subject: RE: [Milsurplus] ATD Transmitter

 

Hi,

I found that 100 pf with my GRC-9 produced less power output into a 50 ohm
load that a 50 pf did.  I tried a variable and found different values
changed the tuning (of course) but didn't change the power output much
between a little less than 50 pf to about 80 pf  then it dropped off with
either less or more.  I would suggest trying 50 pf or so and see if you get
more output.  I know the ATD is different but I feel it is worth a try if
you haven't done so yet.

Rian



-----Original Message----- 
From: w7qho 
Sent: Sep 30, 2008 9:21 PM 
To: Meir-WF2U , Milsurplus at mailman.qth.net 
Subject: RE: [Milsurplus] ATD Transmitter 


On Sep 30, 2008, at 7:56:40 PM, Meir-WF2U <wf2u at ws19ops.com> wrote:

Then I proceeded to hook up a 100pF cap in series with the output and the 50
ohm load, now the PA tuning is better and I'm getting almost 30W out.

I had to use a series cap for 50 ohms also.  Don't remember exactly what
size.......

 

--

Dennis D.  W7QHO 

Glendale, CA


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