I had the same sort of mixing - part of the reason was I had a non
conductive top bearing
so the mast down to the rotator was "hot" One day I noticed if I cycled the
rotor brake
(the old pre brake delay model) the mixing would come and go. So just took
some aircraft cable and made up a connection that essentially shorted the
top and bottom of the rotor together . Fixed it . Later I added another
cable to connect the mast to the tower at the top of the tower - belt and
suspenders plus probably a good idea anyhow as I thought about it .
So I wonder if some of the mixing might be taking place in a metal thrust
bearing at top that has enough lube or corrosion to sometimes be
intermnittent ??
73 Hank K7HP
Date: Tue, 20 Oct 2015 10:34:42 -0500
From: "Bill Parry" <bparry@rgv.rr.com>
To: "'towertalk reflector'" <towertalk@contesting.com>
Subject: Re: [TowerTalk] RFI Broadcast Station Mixing in Crank-Up
tower?
Message-ID: <001801d10b4c$d7c0eca0$8742c5e0$@rr.com>
Content-Type: text/plain; charset="us-ascii"
I have the mixing problem and my tower is not a crank up. It is 120 feet of
Rohn 25 with insulated guy wires. I notice it on 160, 80, and 40. I have no
idea what is causing it.
Bill W5VX
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Rich
Hallman - N7TR
Sent: Monday, October 19, 2015 9:03 PM
To: towertalk reflector
Subject: [TowerTalk] RFI Broadcast Station Mixing in Crank-Up tower?
Has anyone had any problems with intermittent mixing from a close broadcast
station with a Crank-Up tower? I think I may have an issue with one of my
towers. Cranked up I hear mixing all over 80 meters (Every 10
KC).....Cranked down its gone. I already eliminated the antennas. Mixing
gets very intermittent in wind as the tower moves around.
Thoughts about grounding the top section to the bottom when fully extended?
Was thinking of grounding the coax at the top and bottom of the tower?
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