[Elecraft] KPA1500 RFI on 12m

[john at kk9a.com]

I have a C3 that I brought to St Croix and operated as WP2AA. It has no 12m
elements however the manual states it will work on 12m with a tuner although
I am not sure what the pattern would be. I am not a fan of using out of
resonant antennas and do not even have a tuner in any of my K3S's. I wonder
what the C3 SWR is on 12? The KPA1500 specs are for a maximum SWR of 3:1,
perhaps an external tuner is needed?

John KK9A



eric norris WD6DBM wrote:

My Force 12 C3 antenna is not resonant on 12m.  Using the K3 barefoot, the
internal atu tunes the antenna fine.  Bypassing the K3 atu, but still
running barefoot into the KPA1500 atu, the KPA atu loses it's mind and goes
in and out of TUNE mode uncommanded.  Even though the KPA has found a match,
trying to transmit through it at the 100w level is impossible because of the
constant retuning.
I have put my small collection of mix-31 ferrites on the antenna output,
input, and KPA control line at the KPA, each at a time, with no success.
Any ideas?  I would like to be able to run the KPA at least a few hundred
watts to have the proverbial snowball's chance to break the VP6R pileup on
12m CW.
Any useful comments appreciated.
73 Eric WD6DBM