[Elecraft] Incorrect Voltmeter Reading

[Fred Bongard]

While checking the power output of my K2, (3600's serial #), I noted 
that the voltmeter reading is incorrect. I am using a 50 Amp (yes, 
fifty Amp) Astron power supply with 4 ft of 16 ga wire going to the 
radio. The Astron is set to provide 14.1 V. Using a DMM (and my trusty 
Simpson 260) I read 14.0V at the power plug going into the K2 while in 
receive. The Elecraft internal voltmeter reads 13.5 VDC. On transmit, I 
get 13.9 volts at the plug and 13.1 volts on the Elecraft voltmeter.

It gets even more interesting. My antenna is a SteppIR vertical which 
typically has a 1.4-1.7 VSWR on all bands (I still need to do a bit of 
calibration to get it flatter). On those bands with the best match, I 
get about 15W out of the K2 (no antenna tuner) and the Elecraft 
Voltmeter reads 13.1 V while the DMM still reads 13.8-13.9VDC. On those 
bands with a little higher VSWR, the output of the Elecraft drops to 
10-11 W and the voltmeter reads 12.8-12.9 VDC while the DMM still reads 
13.8-13.9VDC. I am measuring the power output with a Bird and a 100W 
slug. In all cases I have the power set for max on the K2. When its 
output (and voltage both drop) the K2's power meter also drops to about 
6-8 W (in which case the power output actually exceeds the power 
"request" on the dial). When I operate into a dummy load, I get at 
least 15W out on all bands, with the power meter reading about 15, but 
the voltage display still drops to about 13.1 VDC (Current is about 2.5 
A according to the K2). Receive appears to function normally.

I would appreciate any thoughts about 1) the apparently misreading K2 
voltmeter and 2) the precipitous drop in power with a relatively small 
SWR

Thanks

Fred Bongard
WB6JLL