[Milsurplus] BC-611 power

[J Forster]

   From: "Richard Arland

Hi John:

 Thanks for the input. My thoughts were originally to have them make
separate
 dc-to-dc converters for each radio, but then, after reading your post,
I
 think that maybe a generic converter might be a better idea. One that
would
 put out 1.5, 3, 6.3 & 12 V dc for filaments,


Actually, I did not suggest making filament voltages by conversion. IMO,
it's pointless as most sets can be run on 1 to 8 dry cells (C or D). No
converter is 100% efficient and why waste up to 50% of your battery life
making useless heat?  It only makes sense if you are going to use a car
battery or some such the primary power source.

-John


various bias voltages and a
 selection of B+ outputs all from a single unit. SMD would be a definite

 option to keep things small. Anyway, more inputs are welcome. I will
take
 these present them to Dave for his review.

 Again, thanks guys.

 73 Rich



 | It's a relatively straight forward task. I roughed out a design for
an
 | inverter to run a WS 58 (Canadian, 6 to 9 MHz). It had a 555 as a
clock
 | running about 120 Hz, a flip-flop divide by two to ensure symmetry, a

 | quad gate to ensure the oscillator was running and protect the output

 | FETs, a 24 V CT Radio Shack filament transformer run backwards and a
 | bridge and single stage, full wave, doubler (the 58 set needs both 90

 | and 180 VDC). There was also a small full wave tripler off the
primary
 | side of the transformer to make a -21 V C bias. I used a small reed
 | relay, rewound with heavy wire, in the filament line so the inverter
 | would come start when the set was switched on.
 |
 | The whole thing required 8 C or D cells (2 for filaments, 6 for HT)
and
 | I figured 30 to 40 hours per battery set with Alkalines.
 |
 | I never got to packaging it for the set, but I know it worked.
 |
 | -John