It would be even better if you could tandem 4 pots to vary the bandwidth
of the whole filter and 4 more to vary the center frequency just like the
old Autek filters. As a matter of fact, if you can find an Autek, maybe
you can just patch it in to your existing circuit and be done with it. I
have a couple of these filters here i the shack and they are great.
Putting one in line with the agc system would be awesome! Usually you can
find these for about $35 on the used market.
> > I pulled out the QST issues referred to in a recent post here and
> found the one about adding a cw filter to the 540/544 very interesting.
> (for reference, QST Sept 1081, p. 16). I also checked out the audio
> filter (TT 245) and, with an assist from "Solid State Design for the
> Radio Amateur", figured out how to lower the bandpass center frequency
> a bit. By my figuring, one only needs to add a paralleled capacitor
> of a value of 240pF to 330pF to the 8 caps in the filter
> freq-determining circuitry. Now the only thing left is to figure out
> a non-invasive way to switch in the 4 sections of the audio filter
> one at a time. It might mean an outboard box (as in the Sep '81 QST
> article on adding a crystal filter).
>
> 73 K7GT / AE6TT
>
> --
>
> Allan G Taylor
>
> agtaylor@llnl.gov
>
>
> --
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>
>
Steve Ellington N4LQ
N4LQ@IGLOU.COM
--
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