[HBR] Using a BC-453 BFO

[B Smith]

Can I post your results to my BFO page? Could you 
take a photo of the
your temporary test setup?

73

breck

--------------------------------------------------
From: "Ian Wilson" <ianmwilson73 at gmail.com>
Sent: Friday, June 17, 2011 1:38 PM
To: "HBR Receiver List" <hbr at mailman.qth.net>
Subject: [HBR] Using a BC-453 BFO

> I dug out a BC-453 BFO coil (5852 I think) and a 
> 6C4.
> The following components were selected only by 
> being close to hand:
>
>  - plate to pin1 of the coil (no idea which is 
> pin1, which pin3; I was
> lucky)
>  - grid through parallel 47k/0.001uF mica to 
> pin2
>  - B+ through 22k to pin3 (see above)
>  - cathode to ground
>  - solder tag connection to coil metal, grounded
>  - 10pF from grid to frequency meter
>
> This worked over supply voltages from 90v to 
> 250v. The tuning range is
> about 83kHz to 86.2kHz. You would want to follow 
> Breck's modification
> to disconnect the internal variable capacitor to 
> get a bit more range,
> probably.
>
> Note that the original Command Set plate 
> decoupling resistor is probably
> too high (150k) to work with a 6C4 (which is 
> electrically half a 12AU7 and
> is a somewhat high plate-current triode).
>
> Hope this helps.
>
> 73, ian K3IMW
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