Don -
I have gone from bad to worse. I remelted some solder joints, replaced
the 1n5711 diodes, and re-calibrated the tuner. It seemed to work for a
bit, but problems returned. But now the K2/100 also has problems.
With the KAT100 I tuned the antenna to 80m. It worked OK on QRP, but
with the KPA100 engaged the amp shows high reflected and locks on transmit.
I removed the KAT100 and used a manual tuner. Tunes fine at QRP, but
with the KPA100 on, it is like the K2/100 is on a different frequency.
The tuner setting that was fine in QRP now has high SWR. When I go from
20w to full power, the K2 locks in transmit at full power out. I have
to power it off to quit transmitting.
This same set-up, manual tuner, and antenna have worked fine since it
was setup weeks ago.
With a dummy load on the K2/100 all works well. Tried other cables and
yet another tuner with no success. The K2/100 locks up.
Could I have blown diodes in the KPA100 SWR bridge?
Status - KAT100 has wild LEDs and doesn't like high power.
KPA100 doesn't like 80m and locks in transmit.
73 de K1ESE
John
Don Wilhelm wrote:
John,
I believe the problem is entirely in your KAT100.
Check all your connecting cables first thing (do a continuity test on both
the center conductor and shield and check for shorts). It sounds like your
tuner is operating into an open circuit or a shorted one.
If you have an antenna analyzer, check each cable with it while connected at
the far end to a dummy load.
After checking the cables, if you still have problems, try re-calibrating
the wattmeter in the KAT100. Also check the soldering in the KAT100 control
and wattmeter sections - particularly RP1 and the pins of U3. In fact check
all the soldering in the KAT100.
Pins 6 and 7 of U3 must go to a low level (to scale the wattmeter readings)
when high power is active. Check to be certain that is happening and that
the low level scaling signals are getting to pins 2 and 4 of RP1.
73,
Don W3FPR
-----Original Message-----
I had been having problems with my KAT100 and hoped the KPA100 upgrade
would help. I installed the upgrade and all works well with an external
tuner other than the KAT100. But, the KAT100 problems persist.
Here's the problem. The KAT100 tunes fine on all bands into my 50 ohm
dummy load if I set the power to 10 watts. But, if I set it to 11
watts, engaging the KPA100 build into my K2, the bands 160m through 40m
won't tune correctly.
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