[Elecraft] Re: Strange KAT100 Symptom

[Wayne Burdick]

Hi Joe,

Chances are you have more RF getting into the control cable on 17 m than on the
other bands. This will affect the peak SWR readings much more in SSB mode than
in CW mode. It's purely an aesthetic issue--the SWR is no doubt actually close
to 1:1 as indicated in TUNE mode.

We recently updated the KAT100 firmware to revision 1.04, making several minor
changes. One of them was to corrent the tendency for SSB signals to show SWR
higher than reality on voice peaks. This is likely to fix your 17 m problem,
despite the possibility of higher RF on the cable on this band. We now do more averaging.

In addition, Rev. 1.04 lets you install KAT100 jumpers W1 and W2 to override the
K2's normal dot/bar LED modes (as set by the GRPH MENU entry). W1 forces DOT
mode and W2 forces BAR mode. It also fixes a problem on 160 meters. With
revision 1.03, the inductance value for antenna 1, on 160 meters, is lost when
you turn off the K2, requiring a re-tune.

I'll make sure we've added a KAT100 firmware upgrade to our order page.

73,
Wayne


Joe Squarzini wrote:
> 
> My setup is the following: fully loaded K2 #2731 with KPA100 and KAT100
> both installed in EC-2 enclosure. Everything functions flawlessly EXCEPT
> when transmitting on 17m SSB the LED SWR indicators on the KAT100 will
> follow the modulation of the signal up to an indication of 1.5 on the LEDs
> even though the tune function reports an SWR of 1.1. All other bands
> operate according to spec. On the air QSO's report excellent signal
> quality. An external SWR meter shows SWR of 1.1 and a power of 100 watts
> same as the K2 display. One would suspect that RF is getting into the
> KAT100 and affecting the diode display. Why not on other bands? A resonance
> situation only on 17m? The SWR bridge in the KAT100 is reporting the
> correct SWR but that is in response to a CW signal. The CW performance is
> according to spec. Anybody see this before?    Joe