[Elecraft] K3 false SWR indication with SSB

[Mark, KE6BB via Elecraft]

Mark, 

This was addressed several months ago concerning the KX3.  When the software gets ready to display SWR,  it reads forward power, and a fraction of a second later, reverse power.  Since voice peaks go up and down, the displayed SWA will not be accurate unless you use a steady signal.

Mark
KE6BB

-------- Original message --------
From: Mark N2QT via Elecraft <elecraft at mailman.qth.net> 
Date:08/19/2014  12:15 PM  (GMT-08:00) 
To: elecraft at mailman.qth.net 
Cc:  
Subject: [Elecraft] K3 false SWR indication with SSB 

My k3 flashes a higher swr indication with ssb voice peaks than with a steady carrier.

If using an antenna with 1:1 SWR the bar graph flashes the first segment.  If swr is 1.5:1
all the segments illuminate on voice peaks, as if swr was greater than 3:1.  To reduce the 
uncertainty introduced by my antennas,  I connected a 50 ohm load after an external tuner 
so I could create the 1.5:1 SWR, and got the same results.

I assume this is a benign problem and likely caused by the non simultaneous sampling
of FWD and REV power by the CPU.  

However, if no one else sees this I'll do some more checking.

FW 4.81/2.83 and TX Gain Cal done recently.  

Mark. N2QT
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