[Elecraft] KPA500 Band Tracking

[Dauer, Edward]

Thanks, Cliff.  I am aware of the 30M 200W power limitation, but I don’t see why adding 30M to the K3’s Band Map would cause 40 meters and 10 meters to be in error.  When the K3 is at 7.0 MHz the KPA500 switches to 3.5.  When the K3 is at 28.0 MHz the KPA500 switches to 24.9.  That never happened before today.  Moreover the amp correctly senses 30M on the first dit and switches correctly, and seems very happy producing 200W or more on 30M.

Brian, K3KO, suggested disconnecting the cable from the amp to see what the band buttons on the amp do.  They work correctly with the cable disconnected, and they work correctly with the cable connected and the K3’s power off.  7.0 switches to 7.0, 28 switches to 28, and so forth.  So what does that mean – that the fault lies in the K3?  But before adding 30M to the Band map in the K3 changing bands worked for all of 80, 40, 20, 15, and 10 – that is, changing the K3 band changed the KPA500 band correctly.  Now it doesn’t work for 40 and 10, and 30; but it does for 80, 20 and 15.  Since the only change that occurred was adding 30M to the band map, does that mean something is fouled up in the configuration?  I did recycle the power to both the K3 and the KPA500 after making the configuration change.

One other fact – pressing the 10MHz band button on the KPA500 correctly switches the K3 to 10MHz – but places the amp on 5.3 MHz.  The amp then switches to 10 MHz with the first transmitted dit.  But pressing the 10MHz band button on the amp when the K3 power is off changes the amp to 10 MHz.

Appreciative and still perplexed,  Ted, KN1CBR


Edward A. Dauer,  LL.B.  M.P.H.
Dean Emeritus and Professor Emeritus of Law
University of Denver


On 8/7/16, 4:19 PM, "Cliff Frescura" <cf at cfcorp.com> wrote:

    "But the KPA doesn’t track the K3’s band choice correctly."
    
    ...it's by design.
    
    In the US the maximum power on 30m is 200W PEP.
    
    http://www.arrl.org/frequency-allocations
    
    73,
    
    Cliff K3LL/6
    
    -----Original Message-----
    From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dauer, Edward
    Sent: Sunday, August 07, 2016 2:50 PM
    To: elecraft at mailman.qth.net
    Subject: [Elecraft] KPA500 Band Tracking
    
    I must have done something I didn’t mean to do.
    
    Just put up a 30 meter antenna today.  It works fine.  Until today I had the K3 band map set to include only 80-40-20-15-10.  The KPA500 tracked it automatically perfectly.  I then went into the config menu for band map and set 30 meters to IN.   The K3 works perfectly – band switching gives me, in MHz, 3.5 – 7.0 – 10.1 – 14.0 – 21.0 – 28.0 and then cycles back to 3.5  That is also exactly what I expected.
    
    But the KPA doesn’t track the K3’s band choice correctly.  For 80 I get 80.  For 40 on the K3 I get 80 on the KPA500. For 30 on the K3 I get 5.3MHz on the KPA500.  For 20 I get 20.  For 15 I get 15.  And for 10 on the K3 I get 24.9 MHz on the KPA500. 
    
    Interestingly, the “Band” buttons on the KPA500 have the same errors.  In MHz, pressing 1.8 yields 5.3.  3.5 is OK.  Pressing 7.0 produces 3.5.  14 and 21 are OK.  And pressing 28 produces 24.9.
    
    The frequency sampling, however, works perfectly.  A single dit on any band switches the KPA500 to the correct band, as defined by the K3.
    
    The cables are all Elecraft issue.  They are all connected correctly – witness that everything worked perfectly, on every band, until I added 30M into the K3’s band map.  Because both the K3 auto tracking feature and the Band buttons on the KPA500 yield the same errors, I think I must have messed up something in the amp.
    
    I have, by the way, already RdTFM.
    
    Any ideas about what I might have done?  Equally useful would be, how do I undo it?
    
    Many thanks for whatever anyone can suggest . . . 
    
    Ted, KN1CBR
    
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