[Elecraft] KAT-500 Unreliable Tuning

Mon Mar 8 12:07:19 EST 2021

I had a similar issue with my KAT500.  I opened it up and the problem was obvious: there are two green 12g wire bridges that cross. (You can see them in this image: (kat500_inside_500_530x at 2x.jpg <https://cdn.shopify.com/s/files/1/2029/4979/products/[email protected]?v=1536760566>. You can see one end of the longer green wire near the big red toroid.) There had been arcing between them.  My guess is that they arced at higher power levels. I replaced them with slightly longer wires and bent them to create more clearance.  That solved my problem.

I recommend taking taking the cover off and taking a look.  The problem may be obvious as it was for me.

Raj, N2RD

> On Mar 8, 2021, at 10:42 AM, daveingeb at comcast.net wrote:
> 
> Over the past six months my KAT500 autotune function has deteriorated to the point where I am getting frustrated. The KAT tuner is connected to a G5RV via 75' of  RG-8 coax and is fed from a KPA-500 which is fed from a Kenwood TS480. I switch between between barefoot and amplified transmissions. Upon application of a  40 watt tune, the tuner appears to find a suitable solution but when the power is raised to over 100W, the amplifier faults to a high SWR, some bands, but not always repeatable. The antenna and feedline have been inspected and all OK. If I change bands sometimes it works at higher powers and sometimes not. Other times it cannot find a solution on some bands and other bands are OK, low power or amplified. If I cycle the power to the KAT500, it is OK for a while and then it has trouble again. The problem appears intermittent. Wondering if anyone has had this same problem. 
> Thanks de dave WB7ELY
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