[Elecraft] K3 & KPA500 3 days in.

[Rick Tavan N6XI]

You don't have a problem with your 6M setup - it's working well. When you
use the 100W K3 ATU with the amp bypassed, it sees the antenna as its load
and adjusts the match to let the K3 see a 1:1 SWR. When you put the amp in
line, the K3 sees the amp as its load, not the antenna. The SWR seen by the
K3 should be close to 1:1. The K3 tuner can and should be disabled. The amp
sees the untuned antenna as its load, including any inherent mismatch. The
SWR displayed by the amp won't necessarily be the same as what the K3 saw
without its tuner because of SWR metering calibration differences and
variations in apparent SWR along varying lengths of feedline. But the K3
tuner is irrelevant when the amp is in line. It can't change the SWR seen by
the amp and the amp can't change the SWR of the antenna. If you put a high
power tuner between the amp and the antenna, then it should be able to tune
out the SWR seen by the amp. Elecraft has announced a future KAT-500 (1000?)
that will do this or you can use a third-party product.

73,

/Rick

On Tue, Jun 21, 2011 at 7:39 AM, r miles <greenacres113 at charter.net> wrote:

>
> One curious note. My SWR on the 6m antenna is apx 1.4:1. Good enough for
> the amp. I tapped ATU TUNE with the amp off & the K3 easily went to it's
> normal  1:1 SWR. When I keyed the amp the SWR LEDs  are showing  apx
> 1.2/1.3:1 SWR.  The K3 reads 1:1 SWR either way.I don't know if it
> actually is that or what. During xmit with the amp it shows better SWR
> consistantly. Haven't tried the HF antennas yet.
>
>
-- 
Rick Tavan N6XI
Truckee, CA