I want to see them test rigs for cw recption by using an artifical QRN
generator and a code copying program. They could do this at different
bandwidths. Then do the same test with a panel of cw operators who simply
listen to the cw through this QRN and give a subjective rating of 1-10. I
think the results might be surprising.
Steve N4LQ
-----Original Message-----
From: "Tom Rauch" <w8ji@contesting.com>
To: wa3fiy@radioadv.com, tentec@contesting.com, Duane Grotophorst
<n9dg@yahoo.com>
To: <tentec@contesting.com>
Date: Wed, 1 May 2002 09:10:40 -0400
Subject: Re: [TenTec] Jupiter Bashing/eHam Reviews
> > True indeed, so far most of the measured testing done
> > at the ARRL and their peers is focused on the RF
> > signal handling traits of a radio, little or no
> > testing is done with overall RX system distortion of
> > complex (voice type) audio signals. Nor is there any
> > meaningful measurements done to determine the overall
> > contributed noise of the RX's RF/IF and AF stages. The
> > tests they do are very valuable, but they only tell
> > half the story of how a particular RX really performs.
> > That unfortunately leaves some very measurable
> > parameters up to subjective interpretation.
>
> It's unfortunate that we have decided the lack of useful data somehow
> means all data is useless, and that many have concluded measurements
> are meaningless.
>
> Part of this is because some parameters are not measured, another
> part is because we often don't understand what the measurements
> actually mean.
>
> All of this can be corrected. The ARRL is *very* responsive to
> reasonable suggestions for testing, as proven by changes they have
> recently made in response to input from reflectors like this one.
>
> For example...in the past the ARRL published only 20kHz and wider
> blocking and IM3 tests for receivers. Those measurements are useless
> for close-spaced performance of a receiver because they are outside
> the bandwidth of most roofing filters, and the wide spacing test
> hides IM and blocking problems that appear after the roofing filter.
>
> After some conversations on the Topband reflector, the ARRL changed
> to include 2kHz spacing tests. The closer spaced testing sorts out
> second mixer and later stage problems in receivers, and makes a
> surprising change in the pecking order of rigs.
>
> As I understand, they are now going to include CW transmitter
> bandwidth measurements.That's something else that was long overdue,
> as anyone who works CW on crowded bands probably has noticed.
>
> If anyone has any suggestion, maybe we can hash it all out and make a
> reasonable suggestion to the ARRL to include a few more tests.
>
> Perhaps an audio response test and detector IM test would also be
> useful to those who are more "sound oriented" in preferences.
>
> Perhaps someone would be willing to write an article describing how
> to tie measurements into real-world operation. That would be
> extremely useful to correcting the myth that measurements are
> meaningless.
>
>
>
> 73, Tom W8JI
> W8JI@contesting.com
>
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