Folks,
I am trying to understand some odd KPA1500 operation on 6 meters. When
setting the power output of my K3 to give varying amounts of drive to the
KPA1500, I am seeing SWR as displayed on the KPA1500 changing by a significant
amount depending on the drive level. This is with the KPA1500 tuner bypassed.
An LP-100A on the output of the KPA1500 is also used and displays the correct
low SWR at all drive levels that I would expect to be seeing on the KPA1500
display.
For example, with 5 watts drive from the K3, I see 1.3 SWR on the LP-100,
and 2.5:1 on the KPA1500 display. As I increase drive, the KPA1500 SWR display
goes down proportionally, until I get to about 40 watts drive. At the 40 watt
drive level, I am seeing a nice healthy 1600 watts output, and both the LP-100
and the KPA1500 are showing the same 1.3 SWR. 15 watts drive shows 1.3 on the
LP100 and 2.0:1 on the KPA1500 display. So I am not sure why the SWR sensing
and display in the KPA1500 is behaving this way? I do not see this oddity on
any other bands.
I might also add that attempting to get the KPA1500 internal tuner to
bring down the high SWR as seen on the KPA1500 results in a drop in SWR
displayed on the KPA1500 to where SWR almost equals that on the LP-100, but
using the tuner I would expect that to be even better.
--Ed—
--
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