TS-180 self oscillating

[LU1IBL]

Hi

I'm having somew trouble with my TS-180, on perfect matched antenas or without using linear amplifier, but when antena is not very good or with more than 300W the rig begins self oscillating. Any ideas?
Best Regards

Marcelo LU1IBL

 

[Road Squawker]

sounds like RF getting into the PA

welcome to the forum

 

[wavrider]

welcome to the forum.

Try a different coax jumper. different lengths of jumper.

Is the station grounded?

What frequency or band are you having the oscillations on?

 

[LU1IBL]

Hi

Thanks for the welcome and the answers.
I'm just peparing the PA for some tests. I took it out from the rig, and I'm going to test it outside with a signal generator and dummy load.
In case it oscillates i'll take the spectrum analizer to see what is the PA doing.

The oscillation is on all bands.

I bought this rig used, it was a disaster, no RX, repaired it and after that oscillations began.

Grounding, just working on that.

Once I've tested the PA and if there is no self oscillation, I'll check the previous stage.


Thanks a lot

Marcelo

PSE sorry for my English

 

[LU1IBL]

Hi

just checked, odd frequency harmonics, that with signal generator input.
Without input and high Z self oscilations similar to the ones with generator.

tested with rigol DG4162 signal generator
bird 43 wattemeter
DSA130A spectrum analyzer

I asume there is to much gain on that stage, 4 Vpp input full 10W output.

best regards

Marcelo

 

[LU1IBL]

forgot the test was performed on a bird dummy load

 

[wavrider]

maybe be bias is adjusted wrong.

Manual should give procedures on how to align the Pa system.

Good luck on bringing the rig back to working specs.

 

[LU1IBL]

Hi

thanks for the reply

Bias is correct. I'll check the low pass filters on the output