[Elecraft] [K2] Remote KPA100 Bias Current Adjustment

[Brian - N5BCN]

Hi Don,

Perhaps against my better judgement, I adjusted the bias current of the
KPA100 in the KAT100-2 remoted from the K2.  Now I'm thoroughly confused!
:-(

The current measurements of the KPA100 in the K2 make sense to me:
Power < 11 W, Current ~ 380 mA
Power > 11 W, Current ~ 520 mA
Power > 11 + Fan on Lo, Current ~ 565 mA
Add 400 mA for the bias current, and you get a target of ~965 mA.


The current measurements of the KPA100 in the KAT100-2 remoted from the K2:
Power < 11 W, Current ~ 88 mA
Power > 11 W, Current ~ 229 mA

This makes sense to me because the KPA100 is providing power to the KAT100-2
now, which apparently draws a lot less current than the K2 plus options.

Here's what doesn't make sense to me:
Turning on the fan now that it's in the KAT100-2 does not increase the
KPA100's current draw at all, but it makes the current draw of the K2 go up!

The only connection between the K2 and the KPA100/KAT100 is the data cable
connecting the RS-232 ports.  Is this data cable providing current to power
the fan?!  If so, how do I factor all this into figuring out a target for
the bias current adjustment?  Do I add 400 mA to the 229 mA value and be
done with it? 

Thanks for straightening me out!!

73

N5BCN - Brian



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K2 #6800 KPA100/KAT100-2, KSB2, KAT2, KIO2, K160RX, KNB2, KAF2, LP-PAN/K2 w/ Pre-amp, SignaLink USB
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