[1000mp] ARRL testing of Clicks

Wed, 3 Jul 2002 15:01:57 -0400

> > Unfortunately, Tom, most readers don't share our enthusiasm for test
> > data. That is why ARRL started creating the separate test-result
> > reports. 

> That implies amateurs as a group care less if they have nasty signals 
> or not. I do not think that is true at all. 

I don't think that is true at all, either, Tom, and I did not mean to imply
that at all.  IMHO, most amateurs would prefer to be given a plain-English
explanation about things like key clicks, transmit IMD and similar things as
opposed to things like a keying-sideband spectral plot. 

> I think nearly 100% of amateurs, if given CLEAR information or
comparisons, 
> would pick the best radios both for transmitting and receiving.

Agreed. I just feel that such information is better presented as a
quantified statement in the text of the review or the caption.

> While I appreciate all the work you do....I think it is the ARRL who 
> has decided what people need to see in reviews.....not the other way 
> around. 

I am not sure by what means the editors have fathomed what people want to
see in the reviews, other than the fact that people do write the editor and
make their views known.  ARRL has also done a number of surveys of QST
readership to determine what the readers want.  In putting the 30-40 pages
of information into the expanded test reports, more information is made
available than could ever be put into the pages of QST.

> I do too. One thing you could do is publish a bandwidth spec for 
> transmitters under real operation, as has been done with receivers 
> for many years. That would prevent glossing over the facts with 
> creative and/or incorrect verbiage. 

Incorrect verbiage is never appropriate, but when it happens, it is in
error, not a deliberate attempt to gloss over facts, IMHO.  As to bandwidth
in real operation, we have been tossing around some noise-based
measurements, where audio-bandwidth limited noise is put into the microphone
input, the radio adjusted for rated power PEP and the resultant output
measured (with averaging, to wash out the noise).  Another one for the
expanded reports, I think, as we can get it to the point where we feel
comfortable that it is a reasonable representation of what the radio is
doing.

> Then do it by numbers. "The bandwidth of the FT33 is xxkHz at -50dB." 
> That would mean something to everyone.

That could be useful, but limited.  A radio that is 5 kHz wide at -50 dB and
5.5 kHz wide at -80 dB is different than one that is 5 kHz wide at -50 dB
and 25 kHz wide at -55 dB.  While I haven't seen that much variation, I have
seen radios that are similar at close in performance and dramatically
different 25 kHz away. I have seen others whose keying sidebands are
different on the upper and lower sidebands.

> A picture of the keying waveform is a total waste of space unless 
> someone has a magnifying glass and knows what to look for, yet there 
> seems to be room for that! Who gives a crap what the envelope looks 
> like, put it all in numbers. "The IC-706 truncates the leading edge 
> of all CW elements by 2mS when in QSK." 

> Better than showing them one dot and dash, when it clips dots and 
> dashes all by that amount. 

A good suggestion.  I agree, the envelope is hard to interpret.  A very
small region where the envelope amplitude is changing very fast can make a
major difference in the keying sidebands. A raised sine and a more
traditional waveform may have the same rise and fall times, but a
dramatically different spectral occupancy.  I am not sure what you mean by
one dot and one dash -- the keying envelopes in Product Review show two
dots, the first and the second after the initial key closure.  If one looks
like a dit it is because the radio is seriously truncating the first dit
more than it does the second.

> If you said one word in a review about a radio having a useless silly 
> ratio control and lacking a weight control, it would probably make it 
> back to the engineer and the problem would go away. Just like clicks 
> would.

> It's our job to educate the inexperienced new engineers in how these 
> systems actually work, before we all die and no one knows how any of 
> this stuff is supposed to work. It's time to work on this.

I will pass this along to the editors, but I am sure that they have already
heard this directly from you.  Believe it or not, member input often has
more weight than that of the ARRL Lab staff. 

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

> -----Original Message-----
> From: Tom Rauch [mailto:[email protected]]
> Sent: Tuesday, July 02, 2002 11:35 PM
> To: [email protected]
> Subject: RE: [1000mp] ARRL testing of Clicks
> 
> 
> > Unfortunately, Tom, most readers don't share our enthusiasm for test
> > data. That is why ARRL started creating the separate test-result
> > reports. 
> 
> That implies amateurs as a group care less if they have nasty signals 
> or not. I do not think that is true at all. I think nearly 100% of 
> amateurs, if given CLEAR information or comparisons, would pick the 
> best radios both for transmitting and receiving.
> 
> While I appreciate all the work you do....I think it is the ARRL who 
> has decided what people need to see in reviews.....not the other way 
> around. 
>  
> > Having said that, though, I believe that things like good or bad
> > keying, or even transmit IMD results, should be discussed more
> > thoroughly in the running text.  That will probably have more of an
> 
> I do too. One thing you could do is publish a bandwidth spec for 
> transmitters under real operation, as has been done with receivers 
> for many years. That would prevent glossing over the facts with 
> creative and/or incorrect verbiage. 
> 
> > impact that would publishing a keying-sideband photo that 
> has meaning
> > to only a relatively small subset of hamdom.  To do that, however,
> 
> Then do it by numbers. "The bandwidth of the FT33 is xxkHz at -50dB." 
> That would mean something to everyone.
> 
> A picture of the keying waveform is a total waste of space unless 
> someone has a magnifying glass and knows what to look for, yet there 
> seems to be room for that! Who gives a crap what the envelope looks 
> like, put it all in numbers. "The IC-706 truncates the leading edge 
> of all CW elements by 2mS when in QSK." 
> 
> Better than showing them one dot and dash, when it clips dots and 
> dashes all by that amount. 
> 
> > IMHO it is critical that it be done as uniformly as possible. 
> 
> Establish a uniform test, and hold 'em all to it! 
> 
> You just watch and see how much better gear gets when people 
> understand how things really compare.
> 
> Few of the manufacturers even know what the heck weight is any more. 
> They think ratio is weight! W9TO got it right in 50's, Curtis got it 
> right in the 70's, MFJ got it right in the 80's. Now most radio 
> designers working for manufacturers haven't a clue how to build a 
> keyer, and we depend on them to eliminate clicks!!! 
> 
> If you said one word in a review about a radio having a useless silly 
> ratio control and lacking a weight control, it would probably make it 
> back to the engineer and the problem would go away. Just like clicks 
> would.
> 
> It's our job to educate the inexperienced new engineers in how these 
> systems actually work, before we all die and no one knows how any of 
> this stuff is supposed to work. It's time to work on this.
> 
> 73, Tom W8JI
> [email protected] 
> 
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