[1000mp] ARRL data - 1 kHz IMD and BDR performance

[Augie Hansen]

> > Yep. Check this out:  http://www.sherweng.com/table.html
> >
> > Note some old single conversion boat anchors near the top. Also note
> some
> old, highly thought of boat anchors
> > near the bottom.
...
> I think Sherwood has had the switchable first IF out for over 20 years.
Tom


What you say is correct, Tom. I put all the Sherwood mods in an R4C in the
late 1980s and it is still the best receiver I have, even when compared to
recent and past top-of-the line rigs. Not as easy to use as most perhaps,
but outstanding specs and performance.

The Ten-Tec Omni V listed in Rob's receiver performance comparison chart is
one that I bought and reviewed in Digital Digest magazine (now defunct) in
1989. Rob and I conducted the testing in his lab here in Denver. In my
article I described the use of roofing filters to achieve superior close-in
strong signal performance, and suggested that virtually all receivers could
be improved by using narrow roofing filters early in the signal processing
path that are selected based on operating mode. 

As far as I know, the Ten-Tec Orion is the first ham transceiver to do this,
and the Icom 7800 will go part of the way there with a choice of 15 KHz and
6 KHz roofing filters. Icom claims a narrower filter is not needed for CW
and other narrow modes due to the way they have implemented their
mixing/detection circuits. We'll have to wait and see on that one. I don't
know about Yaesu's plans regarding roofing filters. 

73, Gus Hansen / KB0YH

Email: KB0YH@arrl.net
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