Hi folks,

Should the ATU affect output power from the KX1? If not, here's my conundrum:

After finishing the 80-30 mod, the power output seemed a bit low. As per the instructions, I adjusted turn spacing on one of the two toroids on the new filter board and achieved 4 watts out on 80m and 30m, and 3 watts out on 40 and 20 at 14 vdc.

I reinstalled the ATU, buttoned up the case. With the radio running into a 50-ohm dummy load, and with ATU engaged, I got about 1.5 watts on 80m, around 3 watts on 40m, 4 watts on 30m, and about 2.5 on 20m. These readings came from the internal watt meter, as well as an outboard NorCal wattmeter.

I opened the case again, pulled the ATU, tweaked winding spacing, left the ATU out of the package, and the power levels returned to the original 4/3/4/3. I plugged the ATU back in and the same reduction in power out resulted.

On inspecting the boards, it didn't look as though the ATU was physically impinging on the new filter board. And with the ATU attached, but with both boards out of the case, I was able to tweak windings to get the 4/3/4/3 output again...until the boards went back into the case. Then it was back to 1.5/3/4/2.5ish.

What could be altering the output? The only thing I could think of was that the toroids might be wound a bit tight, so that when tweaking the spacing between windings, the windings basically slide back into more or less the original positions in about the time it takes to close the case. Yeah, it's a reach, but it's all I've got at the moment.

Any thoughts/suggestions? I can try operating without the ATU and use my outboard tuner. But I figured as long as I've got the tuner, I'd like to use it.

With best regards,

Pete

--
Peter N. Spotts -- W1PNS
http://www.w1pns.net
Email: [email protected] | Skype: pspotts
QCWA #34679 | SKCC #4853T | QRP-ARCI #4174
NEQRP #714 | NAQCC #2446 | GQRP #13202

"Amateur radio is a contact sport.
Get on the air and make a contact!"
       -- Lyle Amundson, K0LFV
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