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This came though a listserv. There's a "mystery" signal on 10
meters. The puzzle is that this signal has been heard across the country. ==================== Start Copy == GE er GM, All. Hr flws sig rept 28.635Khz, Time 0508Z (0008R) 4 JAN 2005 Sig recieved on Icom IC-746PRO, equipped with high stability crystal freq standard, fed from GAP Titan DX vertical. Sig taken in USB position after verfifying zero beat in CW of 28.635KHz. Lvl approx S6-7. I then applied sig to MixW program, expanded waterfall to X5 scale, and used CW mode to get a single cursor I could work with. This signal looks like, or very similar to, a carrier tonepack, or a telemetry trace of some sort. The signal is composed of 14 discrete tones, all frequency modulated to some degree, but most constant. the frequencies a 436.0 Hz 705.0 Hz 776.0 Hz 805.0 Hz 831.0 Hz 909.0 Hz 993.0 Hz 1187.0 Hz 1227.0 Hz 1274.0 Hz 1348.0 Hz 1772.0 Hz 1816.0 Hz 2000.0 Hz The 1348 Hz signal was frequency modulated in a slow digital pattern and also amplitude modulated in a slow digital pattern which did not correspond to Morse, Baudot, ASCII, or any other pattern I could pick off the top of my head. The FM is 24 Hz shift, from 1361 Hz to 1336 Hz. I didn't take the time to measure the amplitude excursions, I wanted to get this posted, because I',m getting kind of tired --hi--... I made no attempt to make these numbers work out. I eyeballed the center freq of each waterfall trace, as well as the edges of the FM modulation of the 1348 Hz trace. It was only after I looked at all the numbers did I realize that they all were exact freqs, I.E. no decimal frequencies, and I was extremely suprised to find the exact 25 Hz FM deviation on the 1348 Hz trace. Given these results I have reasonably high confidence in my findings, and that they are correct. I will continue to monitor this freq tomorrow and see if I can't make some kind of sense out of this. I am reasonably certain that I am seeing a carrier tonepack, or a telemetry tonepack. When I first was looking at the traces, One of them (I forget which now) seemed to be FM modulated as a time reference, as the deviation was all one direction (center downward) and at regular squarewave like intervals. This particular trace ceased the behavior when I got around to expanding the waterfall (naturally) but I am determined to track this thing down and get a handle on it. It doesn't sound like any 16 channel tonepack with which I am familiar, nor any telemetry with which I am familiar, (Yup, I've heard ans 'scoped a lot of them, most of which I still can't talk about), but heck, this is the 21st century--hi-- Thanks to this group for a wonderful mystery!! Sometimes you have to get off the MARS nets, or chasing CW DX all nite, and solve these things (if they can be solved). Since I am retired disabled, I have all the time in the world to pick around at this enigma. Hr fols my QRZ.com info for those plotting the sig repts: QSL Mgr: Buro Coordinates: 39.956267 -75.274357 County: Delaware Grid: FM29iw Area Code: 610 GMT Offset: -5 Time Zone: Eastern Has DST?: Y ==================== End Copied report == I fired up my SB-303. At 9:00 PM EST Jan 4, 2005. I copied the signal S-5. Very readable on a 50 foot piece of wire hanging out my 2nd floor window. I can't add anything to the analysis. de ah6gi/4 |
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