[Elecraft] KAT500 Auto or Manual

[Don Wilhelm]

Kev,

Put the KAT500 in AUTO mode and then let it autotune with a constant CW 
signal (the ATU TUNE will produce the right signal) every 50 kHz across 
each band of use and for each antenna.  Then switch it to MAN mode.

The "problem" is mostly in SSB mode, but can also occur in CW mode.
The reason is that the forward power cannot be measured simultaneously 
with reverse power.
Lets say you are in SSB mode - due to the syllabic nature of speech, 
there will be times when the power is high and times when the power is low.
If the forward power is read during one of the times when the power is 
low and the reverse power is read when the power is higher, it will 
compute to a higher than normal SWR and the tuner will begin a retuning 
cycle if set to AUTO.

73,
Don W3FPR

On 11/18/2017 2:41 PM, Kevin der Kinderen wrote:
> Hi:
> 
> I'm the one that recently reported problems with the KPA500. I've replaced
> all RF cables including the one out to the BALUN and the BALUN itself. I
> know which bands are less than 10:1 in bypass and locked out bands that
> exceed that SWR. Something in the amp just refuses to switch from straight
> through (standby) to amplified (operate) and the radio sees infinite SWR
> with the KPA500 in operate mode. Elecraft had me check one resistor that
> might cause the problem and said further troubleshooting would have to be
> at their facility. While I'm trying to dig up some schematics to help out
> I'm getting the feeling it will be on its way back to E for service
> shortly.
> 
> 
> In the meantime, I got comment about how I run my KAT500: "KAT500 - We
> normally leave the KAT in the MAN position, not AUTO. With varying SWR, the
> KAT will tune while in transmit when in the AUTO position."
> 
> I'm not quite sure what that to make of that. I have my KAT500 in the AUTO
> position thinking it's a good thing that the KAT will tune if something
> happens... which it never does. But in AUTO, at least the tuner will retune
> if I jump to a frequency that is not in memory.
>