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Thursday, October 22, 2015

November 2015 QST -- Wrist Radios, Phase Noise, and a 1958 BITX!


A Early BITX


I liked this issue.  Highlights:

Page 30.  Glen Popiel's article on the Arduino.

Page 33.  I know this may come as a surprise, but in spite of my admitted Ludite tendencies, I found the article on High-Speed Wireless Networking to be very intriguing.   

Page 38.  Hey!  Mike Aiello N2HTT has an article about an Arduino-based CW recorder.  FB Mike!

Page 54.  Review of LNR LD-5 QRP Transceiver. "The LD-5 is actually an SDR in a box with switches and knobs..."  They give a phase noise graph.

Page 58.  Review of Synthesizer upgrade for the Elecraft K3.  Uh-oh.  Phase noise again.  The review says the upgrade results in a reduction of phase noise, but the graphs seem to show an increase in transmitted phase noise on 20 meters as soon as you go 10 kHz from the transmit frequency.  I guess this is a tradeoff for a larger decrease in close-in (less than 1 kHz spacing) phase noise?  But if the objective on the transmit side is to deal with "a major problem with multiple operators in the same band segment in close proximity" resulting from transmitted phase noise,  is this a good trade-off?   Also, it would  have been interesting to know if the reviewer could detect -- by ear -- any improvement in the received signal.  

Wayne Burdick, N6KR, of Elecraft e-mailed us to let us know that there was an error in this QST article.  The original graph in the article showed an improvement in phase noise at close-in frequencies, but it also showed a significant worsening of the phase noise beyond 10 kHz.  THIS CHART WAS INCORRECT.    The Upgrade does, in fact, improve the phase noise performance.  A corrected version of the article appears here:
 
Here is the corrected graph:
 
 

Page 71.  My nightmare.  The WristRig.  The Apple Watch on 40 meters.  Sorry Steve, Dick Tracey did not have The Knack, and tackling the "Apple Watch challenge" is not an indication of "homebrew chops."  Software coding chops yes, but homebrewing is, for me, a different thing.   (But, as we always say, too each his own... And thanks to Steve for the interesting article. )

Page 82.  Ross Hull.  Very interesting article, especially the part about OM Ross's untimely death by electrocution.

Page 100.  "The Cosmophones" by Joe Veras.  Cool pictures (as always) from Joe.  And I loved the first lines:  "What in the world is a bilateral transceiver?  Byron Goodman, W1DX, posed that question in his June 1958 QST review of  the Cosmophone 35."    Wow, four months before my birth By Goodman was writing about BITXs in QST!

5 comments:

  1. Fascinating read about Ron Hull.

    http://www.wia.org.au/members/contests/rosshull/documents/Ross%20Hull%20-%20VHF%20Pioneer.pdf

    Ed KC8SBV

    ReplyDelete
  2. Interesting to see the Arduino CW recorder as many years ago (early 80's) I designed and built a similar thing using static RAM chips and other CMOS chips. Found the circuit and the box which still works . https://www.dropbox.com/sh/9frat9r2gjx1xo7/AAC9wyP9WAxCsck2eu5XbZ6Za?dl=0
    I looked at the circuit and admit I can't even remember how some of it works now as I added new features as I went along. I recall I could speed it up to send high speed CW for meteor scatter. Lots of logic to loop at end of message or end of memory etc. How much easier it is to do this in software nowadays.

    ReplyDelete
  3. The ARRL has already corrected their KSYN3A review. We have the new .pdf file on our web site:

    http://www.elecraft.com/K3/QST%20KSYN3A%20revised.pdf

    See new figure 10 and 11.

    Wayne
    N6KR

    ReplyDelete
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