[Elecraft] K2 transmit low power, high current
Wayne Conrad
wconrad at yagni.com
Fri Apr 29 09:53:31 EDT 2011
Installing T4 correctly appears to have done the trick. Output power
went up and current draw went down, and seem reasonable.
The xmit mixer & buffer output voltages changed after fixing T4, but are
still out of whack:
All measurements Vrms using RF probe, "key down")
Xmit mixer output (U10, pin 4): Expected: 0.16, actual: 0.0009
Buffer output (U9, pin 6): Expected: 0.200, actual: 0.0692
Ratio of Buffer output to Xmit mixer output: Expected: 12:1
Actual: 76:1
I started making a chart of power & current on all bands and for
different power settings, intending to post it here to see if it's as
expected. But something seems odd to me: When I select 5W and key up
with the DL1 attached, the output power (measured at the DL1 with a VOM)
drifts upwards just as it does during TUNE. For example, in the 40M
band, key down output power starts at 5.4W but after 10 seconds is
6.1W. Is that right?
73,
Wayne (still studying for the test)
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