[HBR] Small 100Khz IF transformers

[hbr@mailman.qth.net]

In a message dated 5/5/02 7:24:14 AM Eastern Daylight Time, bob@atl.org 
writes:

> Have you given any thought to using two of these 262 coils?
>  Place the windings in series on each and wind yourself a link
>  coil on each, between the windings. Use this link coil as your
>  coupling between the two tuned circuits. If you experiment a
>  bit, you can likely stick a cap across the link to vary bandwidth.

Better yet, try this:

Connect the two coils in series-aiding but leave one end of the winding free 
(may require destruction of the internal capacitors). Use "bottom coupling" 
like in the DC-500 receiver to obtain adjustable bandwidth. The DC-500 
claimed bandwidths suitable for AM, SSB and CW from 50 kc. IFs made from TV 
width coils, whose Q is probably not as good as the Miller IFs. 
  
>  I've not built this, just a thought. I get them sometimes
>  when it's still early in the AM and I've just had my morning coffee :-)

Great thought, tho!! Only real problem is getting enough of the 262's.

With 2 IF stages and a single transformer feeding the detector, 5 cans would 
be needed - 6 if you use one for the BFO. With 3 IF stages the number jumps 
to 7 and 8, respectively.

73 de Jim, N2EY