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Topics - alleycat

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Utility / GMDSS Station ID #s?
« on: November 29, 2020, 2332 UTC »
Are the station IDs for the GMDSS DSC stations on HF (2187.5, 4207.5, 6312.0, etc.) the same as the IDs used on longwave DGPS stations? I've been monitoring digital signals for decades, but recently discovered I'd missed the easy-to-log HF GMDSS signals - so I fired up DSCDecoder, and I'm seeing short "health" messages with Station IDs, but one of the IDs seem to be from an Asian station, which is unlikely given propagation at the time. Any advice regarding this mode is appreciated! 73 de KC2KLC

I just obtained a SDR-Kits patch antenna, and am decoding (using JAERO) a number of Inmarsat signals from 1545.015 through 1545.205 MHz. I see a lot of info online about these birtds, but none of the positions makes sense. I'm at roughly 75 degrees west, 42 degrees north, and the signals are strongest when I'm pointing south. (I'm on the west side of my house, so I have a clear shot south- west-north but anything at all east would presumably be blocked by the house.) Can anyone tell me for certain which Inmarsat I'm hearing? Thanks and 73 de KC2KLC!

HF Mystery Signals / Natural phenomenon?
« on: November 29, 2020, 0211 UTC »
I'm guessing this is a natural HF phenomenon (meteor?), but I suppose it could be a propagation check of some kind? When I used to monitor radio in the traditional fashion, I'd hear a "swoop" every once in a while - sounded like a carrier sweeping up (and I think it's always up) through the frequency I was monitoring - and once I started SDR'ing, I verified my hunch visually:

Anyone know for certain what this is? Thanks & 73 de KC2KLC

HF Mystery Signals / Marker? On 18.1025 MHz [EDITED]
« on: November 05, 2020, 2356 UTC »
Narrowband marker? going "bippidy bippidy bippidy bippidy" nonstop for days (weeks?) with carrier center at 18.1025 MHz (listed as a W1AW frequency, but this signal doesn't sound like it's carrying data). Audio sample (USB mode tuned to about 18.102 MHz) at https://www.lutins.org/temp/181025.mp3. Thanks for any help ID'ing & 73 de KC2KLC.

EDIT: Corrected the URL; had ".NET" instead of ".ORG" by accident

HF Mystery Signals / 6815-6865 kHz 0120z on 22 Sep 2020 (OTH radar?)
« on: September 22, 2020, 0138 UTC »
50 kHz bandwidth signal with several distinct modes (refer to attached waterfalls). Is this some kind of over-the-horizon radar?

Spy Numbers / CW 5-figure groups (cut numbers?) 6824
« on: September 19, 2020, 2317 UTC »
Seem to be using too many different letters for "cut numbers" - mostly 5-figure alphabetic groups, with some actual numbers as well - not sure of the ENIGMA classification for this one.

Utility / 6507 - French - Maritime?
« on: September 19, 2020, 2304 UTC »
I don't speak French, so I'm curious about the station I'm hearing on 6507 (USB) in central New York State right now (2300) - I heard a reference to Canada, and I'm hearing some numbers repeated (although it's clearly not a numbers station). The cadence suggests maritime weather conditions being related - can anyone confirm? Thanks!

Spy Numbers / V2 on 11.635 LOUD
« on: July 12, 2020, 2103 UTC »
5-figure Spanish female numbers with crazy strong signal in upstate NY - eventually interspersed with digital signals (not sure the mode - haven't monitored numbers in a LONG time). Reading up on it now - presumably V02 interspersed with SK01.

Utility / PPU Observatoriio Nacional (Brazil) 10 MHz
« on: February 08, 2020, 2247 UTC »
At 2245z time station PPU (Observatoriio Nacional, Brazil) is competing with WWV on 10 MHz in Binghamton (upstate) NY (sample at www.lutins.org/temp/PPU.mp3).

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