http://elecraft.85.s1.nabble.com/KAT100-Strange-K2-100-Behavior-During-Tune-tp393891p393894.html
Here is another simple explanation. Perhaps it is voltage drop on
your power supply. You probably have the best match and most power
to test this is to turn the power out down by 30W or so. Not enough
> In this case the antenna is a simple coax-fed 40M dipole with a
> balun at the feedpoint. Without the KAT100 in line the SWR is
> approx 1.2 to 1 at 7100 where the problem occurs.
>
> A quick check shows that yes, the problem seems to occur only on
> 40m. I also noticed that other accessories on the same power
> supply re-set themselves when it happens, supporting the foldback
> limiting theory and the work-around that Tom posted and Mark
> pointed out. However, it happens only when the KAT100 is in line;
> I cannot reproduce it at any frequency or power level when the
> KAT100 is disabled.
>
>
> ----- Original Message ----- From: "Don Wilhelm" <
[hidden email]>
> To: "Jonathan Taylor, K1RFD" <
[hidden email]>;
> <
[hidden email]>
> Sent: Saturday, September 16, 2006 4:47 PM
> Subject: RE: [Elecraft] KAT100: Strange K2/100 Behavior During Tune
>
>
>> If it is RF feedback, the proper way to deal with it is at the
>> source - in
>> your antenna system.
>>
>> An easy way to check it is to cut a quarterwave wire for each band
>> that is
>> troublesome - attach one end of the wires to the ground terminal
>> on your
>> tuner and the other end just stretches out and attaches to nothing
>> excpet an
>> insulator. There will be high RF Voltage on the open end of the
>> wires, so
>> keep them clear of human and pet contact and keep them far enough
>> away from
>> objects to prevent arc-overs (treat the far ends sort-of-like the
>> end af an
>> antenna).
>>
>> If these wires correct the problem, then you do have work to do on
>> the
>> antenna system. If they do not help, then you can look further
>> for a K2/100
>> or KAT100 problem.
>>
>> From your description, I would think something is causing a very high
>> current draw (even for a very short time) - your power supply may
>> be going
>> into foldback limiting and the K2 powers off momentarily. The other
>> possibility is that the resettable fuse in th ebase K2 is tripping
>> and
>> causing the power off condition (yes - it is powering off since
>> you see the
>> ELECrAFt on the display).
>>
>> Is this by any chance happening most frequently on 40 meters?
>>
>> 73,
>> Don W3FPR
>>
>>
>>> -----Original Message-----
>>>
>>> I have a K2/100 with a KAT100. For the most part, all works well as
>>> expected.
>>>
>>> Intermittently, though, when I press the TUNE button, the KAT100
>>> will
>>> chatter briefly as if finding a match, and then it suddenly stops
>>> and the K2
>>> acts as if its CPU has been re-set; the bargraph and the LCD go
>>> blank
>>> briefly, then the ELECrAFt sign-on message appears briefly and
>>> finally the
>>> frequency is re-displayed. During this time, however, the power
>>> supply
>>> indications are normal and the LCD backlight remains on.
>>>
>>> This problem seems to be frequency-dependent and seems to happen
>>> more often
>>> at high power, which leads me to think it is an RF feedback issue.
>>>
>>> However, I've noticed that turning the power down to bottom end
>>> of the
>>> high-power range (approx 12 W) usually doesn't help, yet turning
>>> it slightly
>>> lower than that, to get into the low-power range (approx 10 W),
>>> does.
>>>
>>> Any advice on how to solve it?
>>>
>>> Thanks
>>>
>>
>>
>
>
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