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
AGC voltage.
73, Mike N4NT
----- Original Message -----
From: "geoffrey mendelson" <geoffreymendelson@gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.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.
Geoff.
--
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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