I believe when the 544 is switched to CW one stage of the filter is active.
The second CW position uses all stages. The 544 AGC voltage is derived from
audio. The Ten-Tec filter appears in the audio string before the AGC
sampling point. So to be properly effective, an added audio filter needs to
be put into the audio circuitry before the AGC sampling. If this is not
done, then signals outside the passband of the filter can still pump up the
73, Mike N4NT
----- Original Message -----
From: "geoffrey mendelson" <firstname.lastname@example.org>
To: "Discussion of Ten-Tec Equipment" <email@example.com>
Sent: Monday, July 26, 2010 2:57 PM
Subject: [TenTec] vague answer to the triton audio filter question
>I was looking through a book I bought about 15 years ago that was a
> compilation of QST reviews called "The Arrl Radio Buyer's Sourcebook".
> In it is a copy of the review for the 544. There really was not much
> to say about it, and the review as published in the book, had a full
> schematic of the audio filter and a discussion of components used to
> build it.
> If you have access to the QST review, it would pay to read it. If the
> review is different than the one in the book, let me know and I can
> send you a copy.
> BTW, it was a simple 4 stage active audio filter, using IC's common 20
> years ago. Almost anything similar would do. For example I used to
> have an MFJ 9020 QRP transceiver with a plug in audio filter. If you
> can get one from MFJ, it would be IMHO a suitable replacement.
> The TenTec filter had 4 bandwiths, the MFJ has one, but the 544 only
> used the last, i.e. all four cascaded.
> Geoffrey S. Mendelson, N3OWJ/4X1GM
> To help restaurants, as part of the "stimulus package", everyone must
> order dessert. As part of the socialized health plan, you are
> forbidden to eat it. :-)
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