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I recently got an ATU-100. ?It tunes but doesn't seem to retain the tune. On CW, for example, if there is a brief pause between words, it retunes. ?It seems to do this whether it is in autotune mode or not. ?This means that there is a brief spike in SWR on each transmission after a delay. ? Is this how it is supposed to work? ?I would have assumed it would hold its tune, at least until power was turned off.
Tnx
73 Howard K4LXY

May it isn't retuning. ?Maybe it is just the display. ?When there is a pause in transmission, the SWR readout is high for a fraction of a second and the readout is Tune before showing low SWR. ?I borrowed a friend's and his does the same thing,
Mine is supposed to be version 3.2.
Am I missing something here?
Thanks
Howard K4LXY

I had the same issue with mu ATU-1000. While tuning fine with a single tone, it was retuning constantly on the lower part of 40M band and ONLY on LSB. When I switched to USB there was no issue. This prompted me to do an impedance sweep in this part and while resistance was well within range of the ATU, reactance was looking like a steep hill, rising as frequency was going down. When transmitting in LSB the SWR actually rose with my voice and the ATU-1000 was kicked into retuning, and my TRX into ALC power reduction. I thought there was something wrong with my radio, than with the ATU, but after the impedance sweep of the antenna, I realized it was tad short and below 7.110 SWR rose steeply from increasing reactivity. I lengthened the antenna a bit and now all is fine.

Ah ha - I was indeed using with a uBitx. ?I'll try it with something else.
(It's acting the same whether it is in Autotune or not)
73 Howard K4LXY

I just tried it with a TS-130 I have on the bench and it worked fine. ?Thanks for the tip, Dave. ?And thanks Billian for the suggestion about the antenna. ?I'll keep that in mind.
73 Howard K4LXY