[ARC5] BC-453/Q5er Converter

[Henry Mei'l's]

Dennis,

Do you/can't you use the 3.5 MHz xtal's 2nd harmonic for 40M
in a doubler circuit switched via a ganged toggle or wafer switch?
Why should the mixer have 50 ohm termination when the ant. input of the 
BC-453
probably is not that  (maybe to match available coax feeder line)?
-- surely doesn't really matter because of ample converter output.
( BTW  what is the specified/aprox. actual input Z of a BC-453 and the 
higher freq.
receiver units in the ARC-5 series? -- I would guess, in the same range as 
the xmtrs.
But the BC-453 could also be used with a loop: I have one unit with an "A L" 
switch)

Henry, Cph.



----- Original Message ----- 
From: "Dennis Monticelli" <dennis.monticelli at gmail.com>
To: "Discussion of AN/ARC-5 military radio equipment." 
<arc5 at mailman.qth.net>
Sent: Sunday, September 26, 2010 6:32 AM
Subject: Re: [ARC5] BC-453/Q5er Converter


> Harvey,
>
> I designed and build a two-band (80/40M) solid state converter for my
> BC-453-B.  I built it over a piece of PCB acting as both the ground plane
> and substrate. It was mounted over the Dyno area and fed with the same 
> 12VDC
> that powers the filaments (this ARC-5 was converted when I got it).  I 
> used
> a double-tuned front end preselector in the form of a two-section air
> variable with a torroid for each section.  A small toggle swtich threw in
> extra C for use on 80M.  A JFET Colpitts XTAL osc served as the LO.  Plug 
> in
> a 3.5 rock for 80M or 7.0 for 40M and the dial remains calibrated.  The
> mixer is a Mini-Circuits SBL-1 feeding the source of another JFET
> that serves as the mixer's 50 ohm termination and outputs to a choke load 
> in
> the drain.  A piece of RG-174 skinny coax runs from the converter to the
> front antenna terminal.  I also added a 5K to 8 ohm transformer on the 
> board
> to convert the audio impedance.
>
> It works FB without image, overload or stability problems.  There is some
> conversion gain so the noise of the BC-453 is not a concern.  I've used it
> by itself and also with a T-22 for on-the-air work.
>
>
> Dennis AE6C
>
> On Mon, Sep 20, 2010 at 11:23 AM, <hmitchell3 at comcast.net> wrote:
>
>>
>>
>> I am looking for circuits for an 80 or 80/40 meter converter for the
>> BC-543. I have several old circuits but they involve coils and IF
>> transformers that are not readily available. Solid state is OK, I just 
>> want
>> to finally have a working Q5er.
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Harvey, K5YU
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