Topband: What are these weak birdies every 10.0000 KHz?

[Dan Zimmerman N3OX]

>
>  Apparently rectification in the rotator bearings - or in
> the brake. When I rebuilt all my antennas a year ago I added a flexible
> cable tying the antenna mast to the tower top  and that eliminated the
> issue.


I think the rotator might be a "must check."  I was getting a bursty,
extremely loud birdie on 1830 when the wind blew.

I knew from prior experience that this was a strong local mix at my
location, a loud local 1500kHz AM station with CHU on 3330 kHz.  At first I
was overloading something in the receiving chain, and it was so strong I
could easily switch to AM and pick out both stations.

An AM BCB filter to cut 1500kHz a bit took care of that, but then it came
back, S9 and intermittent.

It was the rotator at the base of my grounded 30 foot mast holding up my 20m
Moxon.  Strapped around the rotor, and it was gone.  If a 30 foot mast and
rotor bearings can create such a loud mix, I can imagine what a taller tower
can do.

73
Dan