[Elecraft] K3 - Power cable voltage drop

tony.kaz at verizon.net tony.kaz at verizon.net
Sun Dec 22 10:47:23 EST 2019


I have been using an Astron SS-30M power supply for several years to feed
two K3's. 
I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
power strip I use 12ga wire to each K3. Total length from power supply to a
K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
tested one at a time. The power supply voltage went from 14.38 to 14.30 at
100W.
Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
and 12.7V at 100W setting on the K3's. The P3 read 107W out.
Changed the cable to 10ga wire direct from the power supply to each K3.
Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
10ga wire.
P3 output was now 114W.
I never transmit with both K3's at the same time.
Just a data point.
73 and Merry Christmas
N2TK, Tony
  



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