[RFI] birdies on 160 and 80

[Stephen]

GA, Guys:

On 160 I have been hearing a noticeable birdie appearing on 1809, 1844, 
1878 every 35 khz.
On 80 I am hearing birdies on 3516, 3551, 3585 and up every 35kHz.
on 160 and 80
Is appears on  and cannot be nulled out with a pixel tech loop.
It appears on both receiving pennant antennas: one NE and one W

It does not appear on my transmitting antenna which is a 1/4 wave on 80 
(direct feed)
and 1/8 wave on 160 (bottom loaded). The transmit antenna is located on 
the end of a 150 foot long
pier over salt water.

The birdies do NOT appear on the other bands from 7-28 Mhz.

Any ideas out there. I have quite a few of my feed lines and other 
interconnecting wires that are choked
with #31. I do not have a choke on the 160-80 meter antenna. I do have 
the pennants and loop choked.

Anyone have any ideas?

Steve AA4V