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Re: [TenTec] Jones filters

To: TenTec@contesting.com
Subject: Re: [TenTec] Jones filters
From: Kevin Anderson <k9iua@yahoo.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 2 Aug 2007 09:34:52 -0700 (PDT)
List-post: <mailto:tentec@contesting.com>
The Jones filter in the Scout and in the Argonaut/Delta II,
while both Jones filters, are similar, yet very different

The filter in the Scout, which I am familiar with, has a fixed
center frequency and is only adjustable in width.  To make the
filtering even more impressive (in my opinion), the center
frequency is set appropriately (or they adjusted the filter
shape somehow) to provide particular filtering of the opposite
sideband/carrier frequency.  The eight crystals of the Scout
Jones filter are set up as two parts, with five crystals in a
fixed filter, and the remaining three crystals used for the
variable part.

The Jones filter in the Delta II is different.  While also a
Jones filter, the ability to adjust the passband center makes
this version a very different animal.  For me, adjusting the
Jones filter was frustrating, the one time I used one, to say
the least, as I continually having to adjust both the center
frequency and width.  After an afternoon of using it, I never
did find the magic combinations to kill opposite sidebands, etc.
 What made things particularly challenging was that I was
operating at friend's house in a contest, where I was
alternating back and forth between times operating with CW and 
with SSB, each of which required different settings of the Jones
filter.  Eventually I gave up and ran the filter wide open,
depending on my ears to do the filtering.

I agree that the use of the Jones filter in the Scout is a very
efficient, yet effective, filter for that category of radio.

Kevin, K9IUA

Kevin Anderson, Dubuque IA USA, K9IUA
k9iua (at) yahoo (dot) com

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