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Author Topic: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020  (Read 851 times)

Offline jasmine

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US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« on: January 15, 2020, 1439 UTC »
I picked up this net talking about windows software updates and security vulnerabilities in clear USB voice after passing what sounded like STANAG traffic (that jet noise whoosh sound).

AFW6T seemed to be net control also heard 6HB, 6HP, 6GO, 6RH, 6DK, 6LD etc all spelled phonetically.

Globaltuners has this as a US Navy MARS frequency no longer in use. Can anyone (Josh?) tell me what I heard?

ps: happy new year to all!

EDIT: it's a US Air Force MARS net
« Last Edit: January 16, 2020, 1602 UTC by jasmine »
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Offline Josh

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Re: Unid MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #1 on: January 15, 2020, 2238 UTC »
Hi Jasmine! When you hear AFA Alpha Foxtrot Alpha in a presumed MARS call, that would indicate USAF, US Army MARS will be Alpha Alpha Romeo, AAR. USN/MC MARS no longer exists as you note. It's common to find USAF and Army MARS members in each others nets too. I helped with traffic to/from Nebraska USN/MC MARS when I was in Iowa USN/MC MARS as I was on the west coast of Iowa, otherwise comms outside your region was pretty much verboten.

For the woosh sound, try psk 110A mode in Sorcerer, 8N1 framing, sync or async can't recall so try both.
The good news is 110A does autobaud and autosync.
The headers will mostly be in plain text, some traffic will be offline encrypted via this app;
https://spi.dod.mil/ewizard.htm
following these protocols;
https://www.mars.af.mil/Portals/59/documents/Regs/AF%20MARS%20MM%2004262016%20RevB.pdf
« Last Edit: January 15, 2020, 2312 UTC by Josh »
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Offline jasmine

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Re: Unid MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #2 on: January 16, 2020, 1601 UTC »
thank you so much Josh! you're like the best teacher of this stuff i've come across. i've seen the term Elmer used to describer teachers in amateur radio and shortwave listening. you're a great Elmer.
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Offline Josh

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #3 on: January 16, 2020, 1922 UTC »
Thank you for the kind words and you're most welcome, always willing to spam any posts with my wit and wisdom or lack thereof.

:D
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Offline ButchKidd

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #4 on: February 04, 2020, 1754 UTC »
sorry for jumping in late here, but I just wanted to throw in a little more on M110A.

For RX only, you can use the same MS-DMT software that MARS ops apparently use.  I don't remember exactly where I found it lately, but I remember a year or so ago MARS made MS-DMT and an unencrypted version of their chat terminal available to amateur radio operators for either Armed Forces Day or one of their quarterly communications exercises.  A Google search should turn up links to both.

It's finicky to get M110A to decode.  Set your audio filter to the full 3 kHz channel, or as wide as your radio will allow.

Even if everything is setup just right, you might not see unencrypted headers anymore.  At least I haven't lately.  I can get a decode with few or no errors that still prints nothing but garbled text.  Reading between the lines of some Facebook posts I've seen, I think they're using online encryption, now.

All my experience with M110A has been unencrypted, so I don't know exactly what encrypted messages should look like at the raw data level other than the modem showing no errors.
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Offline nickcarr3151

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #5 on: February 04, 2020, 2012 UTC »
Most of the MARS 110A traffic is encrypted unless they're doing test transmissions with new users.  The trick with 110A is you need to decode within about 2-3 secs of the transmission start or it can't sync properly.

Sorcerer works pretty well for the most part just be sure to add the ITA2 decoder so it'll be readable.

The encrypted traffic is just garbage upon output.
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Offline jasmine

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #6 on: February 05, 2020, 0107 UTC »
Most of the MARS 110A traffic is encrypted unless they're doing test transmissions with new users.  The trick with 110A is you need to decode within about 2-3 secs of the transmission start or it can't sync properly.

Sorcerer works pretty well for the most part just be sure to add the ITA2 decoder so it'll be readable.

The encrypted traffic is just garbage upon output.

thank you. I have Sorcerer but i never tried to decode 110A. the next time i come across one of these nets using it i will try.
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Offline Josh

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #7 on: February 05, 2020, 0220 UTC »
In the evenings you can usually find some MARS nets just above 80m, from 4000 to around 4060 or so, great place to learn how to set up the decoder for 110A as many of them will pass digital traffic. Used to be MARS would utilise a plethora of unrelated digital modes such as MT63, psk31, and Olivia, DOD said use 110A from now on as that's what DOD uses for similar messaging on hf.
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Offline nickcarr3151

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #8 on: February 05, 2020, 0225 UTC »
Yeah MT-63-1k was in big use a few years ago and it worked well IMHO.  Not sure why they dumped it.  Perhaps it didn't work well with weaker signals and/or poor conditions.
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Offline Josh

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #9 on: February 05, 2020, 1923 UTC »
Yeah MT-63-1k was in big use a few years ago and it worked well IMHO.  Not sure why they dumped it.  Perhaps it didn't work well with weaker signals and/or poor conditions.

DOD wants MARS to be completely compatible with US Mil comms protocols to the extent possible, MIL-STD Data Modem Terminal (MS-DMT) gave MARS the software to comply.
http://www.n2ckh.com/MARS_ALE_FORUM/MSDMT.html

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Offline ZS6AF

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #10 on: February 14, 2020, 1656 UTC »
Very strong signal in South Africa on 4032 khz USB , DATA , no idea what it is , must be local cos i can hear it during  daytime also .

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Offline Josh

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Re: US Air Force MARS net 4623.5 USB 14:32 UTC 15 Jan 2020
« Reply #11 on: February 14, 2020, 1927 UTC »
If you can get a recording we can help sort it out.

Here's one I've often copied from South African forces, very funky mode.

https://www.sigidwiki.com/wiki/Saab_Grintek_MHF-50_MFSK_Modem
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