[ARC5] Transmiitters: Parameters?

[Leslie Smith]

Hello Dennis!
 
You wrote:
"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
 
****************
 
I don't understand your last sentence - and I think "whine" is a typo.
Maybe you meant "while it" or "when" or "will".  Also,  I don't follow
the idea that "... the oscillator provides JUST enough drive for a
SINGLE 1625 ...".  Clearly whoever designed this set - whether Dr. Drake
or another technical (military) type  - "knew his knitting".   Why only
JUST enough for a SINGLE 1625?   What's going on here?
 
 
73 de Les Smith
vk2bcu at operamail.com
 
 
 
On Thu, Mar 24, 2016, at 14:55, Dennis DuVall wrote:
> 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
>
> ****************
>
>
>
>
>
>> 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[1]
>> *Sent:* Wednesday, March 23, 2016 11:33 AM
>> *To:* Howard Holden[2]
>> *Cc:* kgordon2006 at frontier.com ; ARC-5 List[3]
>> *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>
>>> wrote:
>>>
>>> Tried the series cap instead, and it's not nearly as good as the
>>> parallel cap…...
>>
>>
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Links:

  1. mailto:duvallddennis at gmail.com
  2. mailto:holden7471 at msn.com
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