[1000mp] ARRL Lab transmit IMD test-result reporting

[Hare,Ed, W1RFI]

The Expanded Test Result report from now on will include a spectral display
of the measured keying sidebands.

One cannot rely on the rise and fall times as a key click measure.  For all
of the rigs you mention as being clicky, there are sharp transisitions on
keying envelope that contribute to the key clix.

73, 
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis

ARRL is the National Association for Amateur Radio.  It is supported by
membership dues, individual contributions and the sale of  publications and
advertising. For more information about ARRL, go to
http://www.arrl.org/news/features/inside-your-league.html. For more
information about membership, go to http://www.arrl.org/join.html.  Your
contribution can also help support ARRL's ongoing efforts to protect Amateur
spectrum. Go to https://www.arrl.org/forms/development/donations/basic/ to
learn more about the ways you can support the ARRL programs and activities
of most importance to you. You can help ARRL protect Amateur Radio for you
and future generations to enjoy.


> -----Original Message-----
> From: k6se@juno.com [mailto:k6se@juno.com]
> Sent: Tuesday, April 09, 2002 2:41 PM
> To: 1000mp@mailman.qth.net; w1rfi@arrl.org; KC1SX@arrl.org;
> AA1GW@arrl.org
> Subject: Re: [1000mp] ARRL Lab transmit IMD test-result reporting
> 
> 
> Ed, W1RFI wrote:
> 
> "Reviews always pick up on a rig that is overly clicky or has marginal
> IMD, for example.  I, too, offer my feedback to the Product 
> Review editor
> from time to time.  In response to some of the discussions 
> between ARRL's
> test engineer, Mike Tracy, and Tom Rauch, Mike has been putting actual
> measurements of keying sidebands into the expanded reports. 
> Mike reports
> that most rigs he has tested are NOT excessively clicky. ---- 
> As an aside
> to that, some of the worst clickers had rise and fall times 
> that were >1
> millisecond. A careful look at the keying envelope shows that 
> the worst
> rigs often have some small portion of the envelope that has sudden
> transistions -- an almost vertical section of the waveform 
> envelope for
> 10% of the rise time, for example, that generates most of the noise. I
> think that this is an area where the expanded test reports 
> can continue
> to make a positive contribution."
> ==========
> I read the review on the FT-1000MP before I bought one.  
> Although the MP
> is one of the "clickiest" rigs out there, the review did not 
> say this --
> it only presented the keying waveforms.  Icom rigs also have 
> this problem
> -- the IC-775DSP is very bad -- the 756/PRO is slightly 
> better.  Most of
> the Kenwoods seem to be ok.  These opinions of mine are based on
> observations made by me during CW contests and knowing what rig the
> operator on the other end is using.
> 
> With a lot of clicky CW signals occupying 5 kHz of the band 
> (as the stock
> MP does), this allows only 20 such rigs to operate in a 100 
> kHz band, and
> even then weak signals are very difficult to copy amid the clicks.
> 
> I had to modify my MP to reduce the clicks (a la W8JI 
> instructions) and
> one of the prime things I will consider in my next purchase 
> of a new rig
> is how "clicky" is it?  At least then I won't have to modify 
> the rig to
> reduce clicks.
> 
> In your reviews as published in QST, please include a "click" figure
> (i.e., n dB down at n Hz, or something like that).  Maybe that will
> inspire the manufacturers to produce rigs without key clicks.
> 
> 73, de Earl, K6SE (ARRL Life Member)
>