[RFI] Broadcast station RFI Mixing - RESOLVED

Rich Hallman - N7TR rich at n7tr.com
Mon May 26 13:52:43 EDT 2014

After several months of looking for the broadcast mix I finally purchased a HF Direction Finder from http://www.nationalrf.com/type_hfdf_vector.htm.  This really helped me pinpoint where the noise was generating from.  What I found was with the HFDF unit and listening to the loud mix on 3.900, I tracked it down to the new HDX689 tower I installed last year.  I just have a single M2 rotatable dipole up and figured it has to do with that antenna.  After completely disconnecting the antenna and grounding parts of the elements, it didn't help.  I then began moving the M2 15M6 that is mounted on a new model TIC Ring and noticed the noise would get real bad when I rotated the ring.  I then grounded the rotating platform on the Tic-Ring to the tower and the noise went away!

I reinstalled the 80 meter rotating coax and all the cabling while keeping the rotating ring part of the TIC-Ring grounded, and I have no problems.   I removed the ground to the tic-ring rotating platform and the noise came back.

Next question....Anyone have a Tic-Ring that they have had this problem with?   Im just glad at this point I found my mixing issues.


-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Rich Hallman - N7TR
Sent: Saturday, April 19, 2014 6:13 PM
To: rfi at contesting.com
Subject: [RFI] Broadcast station RFI Mixing

Over the past year I have been hearing a local broadcast station on 80 and 40 meters.  80 meters is the worse.  Filters will not help, and sounds like there is something rectifying.  I think I may have a problem on the power pole since it seems to go away for a day or so after it rains.  Also...I have not eliminated that there may be a problem at the broadcast site.  The station is KKOH and is about 10 miles from me...but line of site.

I did a YouTube video of what I am hearing...and for the most part I can hear the carrier every 10 khz...so places like 3900 is real bad.  With the intermittent connection as it sounds like...it messes up the entire 80 and 40 meter band.  Sounds like a bad connection in my antenna...but I have already confirmed my antennas are fine and I confirmed I can also hear the mixing on a mobile 80 meter whip in the truck as well as other antennas.  On 40 its lower signal...but also can be heard every 10 khz or so and the mixing is very intermittent / scratchy.  Seems like its also more intermittent with wind.

Here is the video...   http://youtu.be/rZ8gXRKGkxE

I just emailed my power company the video as well.  Will get the KKOH station engineer to listen as well to make sure they don't have an issue with an insulator or ground on their tower.

Any other thoughts?

Rich N7TR
Telnet: dxc.n7tr.com N7TR DXCluster

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