KAT500 single band fault


David Aslin
 

Consulting the hive mind:

I have for many years used the K3/KPA500/KAT500 combination at home and on 6Gs DXpeditions.  It has been faultless until this week.

Setup: On all bands 20-6m I use an Ultrabeam antenna (same principle as Steppir) so the KAT500 is set to Bypass.  SWR ranges up to 1.2:1 depending on frequency and band

Symptom: the KAT500 and KPA500 fault with High SWR.  The LEDs show 3:1.  This only happens on 12m; other bands work as expected

Fault finding so far: antenna analyser on the Ultrabeam on 12m shows SWR of 1.2:1. 

Suggests antenna OK, so replaced antenna with dummy load: KAT500/KPA500 fault as before on 12m only.

Antenna had been connected to Port 2 of the KAT500; dummy load also connected to Port 2.

Moved dummy load to Port 3.  Setup runs as normal. Moved antenna to Port 3. Setup runs as normal across all bands 20m-6m.

 

Conclusion: there is a problem with Port 2 of the KAT500, but only on 12m.

Suggestions of how to troubleshoot this Port 2 issue with KAT500 gratefully received!

 

BTW, I built all my Elecraft products from kits, so happy to open up the box and do board or component level troubleshooting/replacement; I just need guidance on how to nail down the problem.

73, David G3WGN  M6O