[ARC5] Transmiitters: Parameters?

[Dennis DuVall]

For operating into a 50 ohm load on 75/80 meters I have used a 100pf series cap with command sets and other radios originally designed to operate into electrically short antennas with entirely consistent and satisfactory results starting with my first  BC-457A as a novice back in the 1950s.  Adjust  the series inductor (roller or tapped) to peak the output and then adjust the variable link to give the desired output level, keeping the final dipped along the way of course.  Fifty (50) pf in series about right for 40M BTW.  Using the same capacitors shunting the output terminal to ground forms an “L” network with the rolled inductor which works FB for loading end-fed half wave wire antennas. 

On command sets specifically would recommend putting a shaft extension out the side of the chassis  on the PA padding cap (already an opening there) so you can keep the PA properly dipped.

Ken mentioned PA grid drive on these radios.  The oscillator provides just enough drive for a single 1625 in these sets whine limits the useful power output of course. 

Dennis D.  W7QHO
Glendale, CA

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> On Mar 23, 2016, at 11:47 AM, Howard Holden <holden7471 at msn.com> wrote:
> 
> I got inconsistent results using the series cap (several different values), and as I recall, somewhat greater output with the parallel. And with the SO-239, I simply use a Tee fitting, and run a short cable to whatever cap I want from one end of the Tee, and take the output off the other. I usually use a large air cap. My $0.02.....
>  
> From: Dennis DuVall <mailto:duvallddennis at gmail.com>
> Sent: Wednesday, March 23, 2016 11:33 AM
> To: Howard Holden <mailto:holden7471 at msn.com>
> Cc: kgordon2006 at frontier.com <mailto:kgordon2006 at frontier.com> ; ARC-5 List <mailto:arc5 at mailman.qth.net>
> Subject: Re: [ARC5] Transmiitters: Parameters?
>  
> In what way,,,?
>  
> Dennis D.  W7QHO
> Glendale, CA
>  
> ****************
>  
>  
> 
> 
>  
>> On Mar 23, 2016, at 11:04 AM, Howard Holden <holden7471 at msn.com <mailto:holden7471 at msn.com>> wrote:
>>  
>> Tried the series cap instead, and it's not nearly as good as the parallel cap…...
> 
>  
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