Bad audio only on 6m

[G7SQW]

Hello all,
I have had no problems at all on all bands from 80M TO 10M, but when I transmit on 6m I have been told that I have very bad feedback and I just wondered if anyone else has had this problem on 8m.
My radio is the IC 706,heil traveller headset and either a pro-am monoband whip or a 2m 5/8 ( 1/4 wave on 6m )
I am sure the grounding on my mounts are fine as these as used with no problem on all the HF bands.
Many thanks for reading this and hope someone can offer some words of advice.
Thanks
Andy
G7SQW

[K0BG]

Want to bet? What might work for HF is no guarantee when it comes to 6 meters.

When you speak of grounding the mount, I suspect you're thinking that DC and RF ground are the same. That just isn't the case.

Most likely, the problem is common mode currents flowing on the coax, and if I had to guess, it's the antenna. You can't assume that a 5/8 wave 2 meter antenna will work on 6.

The easy way to tell is, stick a dummy load on the end of the coax instead of the antenna, and see if the distortion is still there.

Alan, KØBG
www.k0bg.com

[G7SQW]

Thanks Alan for replying to my post it was much appreciated.
I will try with some ferrite's on the microphone and antenna cables and will see if this cures the problem.
Andy
G7SQW