[Elecraft] TxMon and K3 (tuner bypassed) SWR missmatch

[Ron D'Eau Claire]

How much coax is between the K3 and P3 monitor? Only a few feet will create
a growing error as the SWR increases, since the standing waves on the
coaxial line produce different readings at different points along the line.

If you want to compare the SWR meters in the K3 and P3, be sure the P3
sensor is mounted directly on the K3 without a length of coax in between.
Even so, the K3 SWR sensor will be "looking" at the P3 sensor through the
KAT3. Although it is bypassed, the older KAT3 ATUs still routed RF through
them on its way to the K3 rear-panel ANT connector. 

Even so, as Fred pointed out, there will be differences since SWR meters are
no "precision" devices because they don't have to be. The K3 is quite happy
at load SWRs up to 2 or 2.5:1 and even above that the amplifier will protect
itself.

73, Ron AC7AC


On 11/4/2016 6:59 PM, dmoes at nexicom.net wrote:
>
> I recently installed the TX monitor in my P3 and have a discrepancy 
> with the SWR reading between it and the K3
>
> with a dummy load connected the P3 and K3 read 1.12 and 1.0
> respectively   a level of error that is to me quite acceptable.
>
> however  when connected to an antenna  I will see the SWR on the K3
> often close to 1:1   when the P3 will show up to a 1:2.   as the SWR
> climbs above 1:2 on the P3  the K3 reading will track it fairly 
> closely but about a level of 1 below.  example
> K3 1:1  P3 1:2,
> K3 1:1.5  P3 1:2.5
> K3 1:2   P3 1:3   and so on
>
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