[Elecraft] Serial Port on K3

[N4CW at aol.com]

Saturday, I was preparing my mobile station for the NCQP on Sunday. I was  
using external power
to my K3 from a fully charged AGM battery. Running 50 watts into a good  
antenna, everything seemed
okay; I made a lengthy 40M CW contact and next hooked up my laptop for  
logging. That's where I ran
into trouble. I use N1MM Logger (ver 12.2.2), the serial port for rig  
control, and the parallel port for 
keying. However, I couldn't get the frequency to display, yet I could key  
the rig using N1MM. To make
a long story short, I found that (using the K3's metering), my supply  
voltage was 12.3 volts. I substituted an AC supply (receive mode only because my 
 inverter/converter was only rated for 75 watts!!!) that puts out 13.8 VDC, 
and  VOILA! I got my frequency displayed.
 
I didn't have time to figure out a solution, so I wound up operating  
without rig control...single band, "rover"
class, CW only, and would type in my run frequency to set the logger. 
 
So, is the K3 serial port supposed to crap out when the rig's voltage  
supply isn't optimum?
 
Bert, N4CW