[Elecraft] KAT500 autotuner odd operation

[dave ingebright]

KAT500-- is a great tuner, but I think they get weary. I bought a second one three years ago because the repair service was taking so long on the first one. Now that one seems to be getting tired. I don't know what the repair service found, except that it came back, and after a while, it started acting strange again. So I have two acting strangely.  Sometimes I get crappy tunes but when I add power, the SWR goes to normal limits, things like that.
Other times, the antenna tunes, and the next day it does not. I have all new coax this month, 100' nominal to the ladder-fed dipoles. (Ladders checked, free and clear) Since the coaxial cables are ~six years old and run underground in conduits from my garage, I replaced them after some checks with the analyzer and cantenna. Seemed not so "flat" anymore.
Since I have three antennas, I select around and use whatever one is acting properly. There's the G5RV high in trees on a ridge N-S, the ZB6BKW about 100 ft away E-W between trees 40', and a SteppIR Small IR in the middle on a metal carport roof. They are all inconsistent, but not enough to put my finger on it. Is anyone else experiencing this?
//dave
WB7ELY

> On 07/15/2025 2:00 PM PDT Graydon Jensen <n7rxl at outlook.com> wrote:
>  
>  
> (private message)
>  
> Thank you for posting this Dave.
>  
> I'm just getting ready to put a new-to-me KAT500 & KPA500 pair in service.
>  
> Please let me and/or the group know, what you find and how things turn out.
>  
> Thanks,
>  
> Graydon
> N7RXL
>  
> 
> ---------------------------------------------
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> on behalf of dave ingebright via Elecraft <elecraft at mailman.qth.net>
> Sent: Monday, July 14, 2025 10:18 PM
> To: elecraft at mailman.qth.net <elecraft at mailman.qth.net>
> Subject: [Elecraft] KAT500 autotuner odd operation
>  
> I have a KAT 500 Autotuner and its been acting oddly for the last few weeks. I am using it connected to three antennas and it will not tune the antenna in the #3 socket. During troubleshooting, I have hooked it to a dummy load, with new coax and it says high SWR. Tuning on the other antennas seems to be suboptimal. It has intermittant high SWR on the other antenna outputs but now #3 seems to always show high SWR. Has anyone seen this or has any ideas? I am running it with a KPA 500, but never over 250 watts. The antenna is a G5RV. The antenna matches OK using the internal FlexRadio 6400 tuner...
> //dave
> WB7ELY
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