[Elecraft] KAT500 question

[Dick Dievendorff]

It depends on the antenna impedance (the unmatched or SWR measured with teh ATU in bypass).

If the unmatched antenna SWR exceeds 10:1, at 600 watts, the ATU might be faulting to protect itself.  

What does your KAT500 fault table say?

The ATU is rated to match antennas with 10:1 SWR at 600 watts, 3:1 SWR at 1000 watts. If the unmatched SWR exceeds 10:1, the ATU might disconnect the amp at a lower power to protect itself from destructive current through its inductors.

It will not match a 20:1 load at 1000 watts.  

73 de Dick, K6KR




-----Original Message-----
From: Tom Blahovici [mailto:tomb18 at videotron.ca] 
Sent: Saturday, November 29, 2014 7:54 AM
To: Dick Dievendorff
Cc: <jsdroyster at nc.rr.com>; elecraft at mailman.qth.net
Subject: Re: [Elecraft] KAT500 question

Hi
Yes erased the 80m and then did a bunch of tunes across the band,  all OK. However,, if I then provide a carrier for more than 3 seconds on a tuned frequency the kat500 starts flipping relays and then goes back to steady only to keep repeating itself. 
In manual mode. That is not supposed to happen in manual mode as far as I am aware. 

On Nov 29, 2014 10:11 AM, Dick Dievendorff <dick at elecraft.com> wrote:
>
> All full search tunes, whether started by manually pressing the TUNE button or an SWR-based autotune, store the tuning solution in memory. 
>
> I'd suggest you erase the tuner settings for 20 meters on the affected antenna connector KAT500 Utility configuration tab) and "train" the tuner by pressing TUNE and provide a 20 watt tune signal on a few frequencies across the band. You don't want remnants of the erroneous settings in those memories, or you'll keep finding them. 
>
> Then leave the ATU in mode MAN so that it selects from previously found tuning solutions as you QSY across the band. 
>
> As for how you got there - I can speculate, but I don't know anything about your path from ATU to antennas.  It probably matched a different impedance at some point in the past.  I might get that result here by having an external antenna switch in the wrong position and use the KAT500 to match my 15 meter beam on 20 meters, and then change my antenna switch. 
>
> You probably don't want the ATU in mode AUTO very often.  After antenna configuration changes, erase the tuner memories on the affected bands, and tune at a few spots on the band.  Then let the ATU choose from those settings by frequency, which it will do in mode MAN. 
>
> 73 de Dick, K6KR
>
>
>
> > On Nov 29, 2014, at 06:17, <jsdroyster at nc.rr.com> <jsdroyster at nc.rr.com> wrote: 
> > 
> > Our KAT500 (used with K3 and KPA500) seems to have forgotten its correct memories for the 20 m band or maybe developed new erroneous memories. It gives me 14 to 1 on autotune.  If I set it on manual and do a tune it reads 1.2 to 1.  So here is the question:  if I do manual tunes every so many MHz across the band will those go into memory, or is  the memory based only on autotunes? 
> > 
> > Also, any idea how this happened? 
> > 
> > THANKS! 
> > Julie KT4JR
> > 
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