Will Martin <wmartin@STL-06SIMA.ARMY.MIL> (02/01/90)
Was tuning around last night, and ran into something I couldn't figure out. Around 0500 on 1 Feb UTC, on 15405 kHz, there were two co-channel signals. One was an interview in English with a Boston bookstore owner, and the tone and general feel of the broadcast was that it was a Christian Science Monitor station. The other signal was in some oriental language and I couldn't get any ID. The strange thing was that NONE of my info sources, including Passport, the ILG, and the recent CSM schedules posted to the net, showed any CSM station, or any other candidate station, on 15405 in English at that time. 15405 was used by a CSM station at a completely different time, though. Also, the oriental-language station couldn't be found in those sources either. There seemed to be absolutely no difference in frequencies between the two signals, with no hets or other signs. The really odd thing was that at 0520 UTC *both* signals faded down rapidly and never came back, as far as I could determine. The BBC on 15400 kHz was still coming in OK, so it wasn't a SID or other kill-the-whole-band propagation disturbance. And they didn't shut down abruptly as if the transmitter(s) were shut off, but faded away. And both signals went at the same time. I'm wondering if one of the following might be the case: There was actually only one transmission, but it was being fed by audio that included two mixed sources -- a tape of the English interview, and a tape of the oriental language, mixed together via some error at a mixing console or audio patch board? Somebody at one of the CSM stations had punched up the wrong frequency for the time of day, and the audio was being fed in error as above? These were a mixing product from a couple transmitters, or some other artifact of transmisson, producing the mixed signal, and someone noticed it and shut down the source(s) in a gradual power-down instead of an abrupt cutoff? Somebody was running tests on a transmitter and feeding it whatever audio was handy just to get some modulation? Anybody have comments? Anyone else notice this? Regards, Will wmartin@st-louis-emh2.army.mil OR wmartin@stl-06sima.army.mil