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Every Monday-night simplex net I've had the same problem: there's some sort of local interference.
I can hear the interference on 146.58 very faintly in the background if my radio's in the right place and tilted at the right angle, but when anyone transmits, it completely overtakes their signal. Even strong, clear signals become impossible to make out.
Today I was able to track down the interference. I originally suspect it was a broadcast station (it sounded like people talking and music, but I couldn't make it out either—it was doubling with other people's signals in weird ways so neither one was intelligible).
Apparently, it's WFIU (103.7MHz). From google's cache, I learned the following:
By 1953, the station had settled down to routine operation, with a broadcast day extending from 12:55 p.m. to 10:15 p.m. Due to the location of WFIU’s 100 foot transmission tower in the center of campus and its impressive 75,000 watt signal strength, small “interferences” persisted. Keith Klein, who worked on the WFIU staff as a student, remembers, “In the days when WFIU’s antenna was adjacent to Read Center, it was legendary that people who lived in the surrounding dormitories could pick up WFIU on their dental fillings, eyeglasses, electric shavers, and such. Some people found that they could hear WFIU on their stereo speakers, even when their stereo wasn’t turned on!” John Harrell, WFIU’s Chief Announcer in the late ‘50s and now a lecturer in the Department of Telecommunications, recalls, “I was living in what is now Ashton Center, and I had a reel-to-reel tape recorder in my room. Well, I listened to WFIU on my tape recorder. I had no need to buy a radio.”
William Kroll notes that the strong presence of WFIU’s signal on campus occasionally caused problems at special events, too. “It was anticipated that our signal would interfere with the dedication ceremonies at the Lilly Library. The university wanted to take the station off the air completely during the ceremonies, but our director, Elmer Sulzer, managed to strike a compromise, and we played an afternoon of very soft music instead. Then there was the time when the rock and roll group The Turtles came to campus to perform. They rehearsed in the morning, and they returned that evening for their concert. When they turned on their public address system, they heard WFIU, loud and clear.” This type of problem was resolved when the WFIU transmitting facility moved to its current location on Sare Road (then the very southeast edge of Bloomington) in 1968. Apparently the only people not satisfied with this solution were the boys of SAE fraternity, who frequently scampered up WFIU’s tower late at night to hang bed sheets scrawled with creative messages.
So I assume that the antenna seen on google maps on Sare Rd. is indeed WFIU's antenna. If so, that's far enough from my QTH that I really shouldn't be expecting any interference, right?
I find that if I don't use my J-pole (and instead my dual-band rubber duck), it's not as big a problem. But then I get worse reception of the other stations on simplex, and don't get much of a signal out, so it's not worth it.
Does anyone have any ideas or suggestions on what might be causing this and how to deal with it? Has anyone else noticed anything similar? Might it be a problem with my radio?
I'll be leaving Bloomington soon and will be most likely be gone for the summer. When I come back in the fall, I'll be moving about two times closer to that antenna (though I'll be nowhere near the awful AT&T building), so I want to start working on this problem now if possible.