[1000mp] Strange effects on 15 and 17 metre bands

[Jim]

I have just acquired a second-hand 1000MP and have been using it with no
problems on 40 and 20 metres for a few weeks now. My main activities are on
CW and data modes.

Today, I tried it out on 15 metres and immediately noticed a problem. If I
let the Automatic tuner do its stuff on CW then all appears OK. However, if
I then switch to USB and use PSK31 (on the same freq as I tuned it on CW) I
get an infinite SWR reading.

I have noticed also that I can get the same effect by tuning up on CW with
the RF power at Maximum and achieving a low SWR and then backing off the RF
power slowly back to zero. When it reaches zero, the SWR shoots up again to
infinity and the power meter jumps up and shows a reading of about 30 watts.

It is almost as if there is some parasitic oscillation taking place. Any
ideas?

Regards

Jim Bryant M0JWB
Portishead. UK.

jim.bryant at btinternet.com



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