[ARC5] BC-453/Q5er Converter

[Leslie Smith]

Hello Dennis,
Your description of the set you designed is full of well written detail.  I enjoyed reading all the detail, and can imagine (or at least imagine I can imagine) both the circuit and the construction detail.  

One detail puzzles me: you mention that the dial stays calibrated when you use a 3500 and 7000kHz crystal.  The  BC-453 dial reads 190 to 550kHz.  Does that mean you lose the lower 200kHz of each band?  (Here, in Oz, our band covers 3500 to 3700kHz. I built a converter, but used a 3200kHz crystal, moving the band to 300 to 500kHz on the receiver dial).

I have run the R-23/BC-453 set with a loudspeaker too.  I used a 600 to 8 ohm transformer.  The volume is adequate in a quiet room.  

Again, thanks for the description of your circuit.  I may design a PC card for a converter similar to the one I have, or perhaps similar to your design.



Les
ex VK2BCU


> ----- Original Message -----
> From: Dennis Monticelli <dennis.monticelli at gmail.com>
> To: "Discussion of AN/ARC-5 military radio equipment." <arc5 at mailman.qth.net>
> Subject: Re: [ARC5] BC-453/Q5er Converter
> Date: Sat, 25 Sep 2010 21:32:32 -0700
> 
> 
> 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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