[ARC5] BC-453/Q5er Converter

Wed Sep 29 23:45:55 EDT 2010

Hello Les,

Yes, I simply meant to say that the dial will cover a 350 KHz spread with an
offset of 200KHz.  I did not explain that well and could have been more
explicit.   I actually use a 6800 rock in mine because I like CW.  7000 is
good for SSB plus SW broadcast.  The actual circuit also accomodates 30M,
though I did not mention that.  If you would like a softcopy of the
schematic and a little writeup just let me know.  There are several folks
that have requested that so I scanned the schematic today.  The circuit is
quite simple and you can substitute just about any commercial
double-balanced diode mixer or merely wind your own.  You can also reduce
the double tuned front to a single tuned circuit at the expense of image
rejection, though with a IF of only 200 550KHz, you can use all the front
end selectivity you can muster.

BTW, my daughter studied for 5 months in Townsville at James Cook
University.  We joined her upon completion for two weeks of holiday up and
down your eastern side.  Lovely country and people.

Dennis AE6C

On Wed, Sep 29, 2010 at 2:51 PM, Leslie Smith <vk2bcu at operamail.com> wrote:

> 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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