[Elecraft] [ELECRAFT]K3:LPA power level accuracy?

[Tony Scesny]

Hi James:

       Use the DL1 dummy load from Elecraft.  Its a great diagnostic 
tool.  It has low inductive resistors 20 watts but will take 90 watts 
for short periods.  Its greatest feature IMHO is the terminals to 
measure the RF voltage.   It has much greater accuracy.    Hook it 
directly to the coax connector on the back of K3.   For power settings 
from 0-12 LP   CONFIG:WTMTR  will show LP and all power above that it 
will show HP.   Now  [disp] will show the defaults of 70 for LP and 30 
for HP.    Set power for LP at 10 watts  and the voltage reading should 
be around 15.4 volts  and 90 watts at 35.65 volts.  Adjust LP or HP to 
correct the voltage.  The change won't be linear so watch it.   After 
changing the LP and HP re-run the 5 and 50 watt calibrations.   As the 5 
and 50 watt cals are running you can watch the resulting voltages as 
each band changes.  (5 watts is 10.9v and 50 watts is 35.65 v) for 
reference.  There may be a particular band you want greater accuracy, so 
you may want to interpolate to get the best average, since it is NOT PER 
BAND.   My K3 showed  LP of 70 was OK but I changed HP to 40 to get 
greater accuracy at 90 watts.

    Don Wilhelm corrected the formula listed in the DL1  sheet.    Watts 
   =  (Vdmm + Vdiode} ^2  / 25  where  Vdiode is assumed to be 0.3 v.

73 and have fun   Tony   K2ZLS at optonline dot net