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Old January 5th 05, 03:54 AM
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Default 28.635KHz mystery signal.

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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