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 future. Dick K9RT In a message dated 11/2/2017 10:41:52 A.M. Eastern Daylight Time, radi...@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. Jerry, K4SAV _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband