Topband: Rotator creating spur on 1820
K9RT at aol.com
K9RT at aol.com
Thu Nov 2 12:41:27 EDT 2017
Interesting you have the spur on 1820.
I have the exact same situation on 1820 as well. Sometimes I can actually
pull weak audio off the spur but have not been able to identify which local
station or stations are mixing to create the spur.
It never varies in strength and I just assumed it was part of the hazards
of operating on topband. Didn't consider it might be the rotor and or cable
going up the tower. In my situation it hasn't caused enough interference to
detract form DXing so far in at lest 20 years +.
Good information to have for those closer to AM broadcast towers in the
In a message dated 11/2/2017 10:41:52 A.M. Eastern Daylight Time,
RadioXX at charter.net writes:
I have a problem for which someone on this forum has the solution. I
know that because I have seen that message sometime in the past.
The problem is that my rotator is rectifying a couple of AM station
signals and creating a spur on 1820. It's normally pretty weak on my
receiving antennas but sometimes it's a problem. I found that if I
listen on my XM-240 near that rotator it can be very loud. As soon as I
move the rotator it causes the spur to go away, or become weak. A few
minutes later it is back again. It pops in and out.
So who had the problem and how did you fix it?
Note that my XM-240 actually shows a low SWR on 160. That's because the
XM-240 balun doesn't work well on 160 and the common mode currents on
the feedline couple to the tower and the tower becomes the real antenna
on 160. So in this case the tower is the antenna and it has that
rotator cable against it picking up max signal from that cable (also
radiating it to my other antennas). No, the XM-240 is not used on 160
(except to find the source of this problem).
The rotator is a Yaesu G-2800DXA.
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