HF 39 Tone Modems

blantonl · #1 (**permalink**) 06-19-2008, 09:35 AM

I've noticed quite a bit of 39 Tone Modem activity on HF, especially on the USAF HF ALE Network, but quite a few others on 10-11 MHz.

I assume this is being used for HF Email... however, does anyone know if there are any decoders available to decode this traffic? Is most of it encrypted? Is any of it non encrypted and recoverable?

prcguy · #2 (**permalink**) 06-19-2008, 11:32 AM

Look for PC ALE, it will display unencrypted ALE traffic with your computer sound card. Much of the ALE traffic is for selective calling or sounding for the best band before establishing voice comms.
prcguy

Quote:

Originally Posted by blantonl

I've noticed quite a bit of 39 Tone Modem activity on HF, especially on the USAF HF ALE Network, but quite a few others on 10-11 MHz.

I assume this is being used for HF Email... however, does anyone know if there are any decoders available to decode this traffic? Is most of it encrypted? Is any of it non encrypted and recoverable?

blantonl · #3 (**permalink**) 06-19-2008, 11:35 AM

No No No... MIL-STD 188-110 39 Tone Modems... not MIL-STD-188-141 ALE.

I'm very familiar with PC ALE ;-)

mtindor · #4 (**permalink**) 06-19-2008, 11:38 AM

Quote:

Originally Posted by prcguy

Look for PC ALE, it will display unencrypted ALE traffic with your computer sound card. Much of the ALE traffic is for selective calling or sounding for the best band before establishing voice comms.
prcguy

I don't think that's what Lindsay means. Lindsay is using PC-Ale to copy the ALE transmissions. but ALE transmissions aren't all that happen on the ALE netowrk. SSB and various digital modes can be heard from time to time, and those digital modes heard are often encrypted (or so I'm told by the WUN folks)... I've heard some digital stuff from some MARS operators - I forget the mode, something I'm not used to but which I copied once somebody told me what it was.

But i think what Lindsay is referring to is specifically some digital transmissions that you hear from time to time on the ALE freqs, some of which are using encryption.

Mike

mtindor · #5 (**permalink**) 06-19-2008, 11:40 AM

Quote:

Originally Posted by blantonl

No No No... MIL-STD 188-110 39 Tone Modems... not MIL-STD-188-141 ALE.

I'm very familiar with PC ALE ;-)

See references to TADIL I think - there are options for encryption with it I think, which are most often used.

Mike

blantonl · #6 (**permalink**) 06-19-2008, 11:45 AM

TADIL is based on the Link-11 Protocol... I'm referring specifically to MIL-STD 188-110 39 Tone Modems.

Is anyone decoding this protocol? How pervasive is clear text transmissions vs. encrypted?

mtindor · #7 (**permalink**) 06-19-2008, 11:54 AM

Quote:

Originally Posted by blantonl

TADIL is based on the Link-11 Protocol... I'm referring specifically to MIL-STD 188-110 39 Tone Modems.

Is anyone decoding this protocol? How pervasive is clear text transmissions vs. encrypted?

Ok, well I guess I never tried monitoring the 39-tone modems. But in general, pretty much anything digital on those freqs seems to usually be encrypted. At least every time I had heard something that I'd never heard before and ran it by some of the guys on #monitor, they've mostly come back and told me its encrypted and that's why I wasn't decoding it. So I'd say more often than not, if it's a digital mode it'll likely be encrypted.

Of course I don't spend all my days and nights listening, so what I've heard has been somewhat limited. Just my experience.

I'm not even sure if I've ever heard the 39-tone modems you are referring to...hmm.

mike

EricCottrell · #8 (**permalink**) 06-19-2008, 01:46 PM

Hello,

It anything can decode it, Hoka can! Big $$$$.
http://www.hoka.net/code300-32/mil188-110_39_tone.htm

73 Eric

blantonl · #9 (**permalink**) 06-19-2008, 01:51 PM

Yea, we'll, Hoka Code is $7295.00 and $11,995.00 for the standard and pro versions.

Wow that is expensive!

I think SkySweeper supports this as well... I'll have to take a look at that sw and see if it fits the bill....

blantonl · #10 (**permalink**) 06-19-2008, 02:05 PM

Anyone out there using SkySweeper? It looks good on paper - however many of the eham reviews say this application is terrible.

lurking · #11 (**permalink**) 06-20-2008, 08:52 AM

You will not get a decrypted message. I have heard there are times they are just testing the equipment in unencrypted mode. I have not seen it.

With Hoka or Skysweeper, you will see the raw data stream. Program decoder or signal decoding is not the same as reading the encrypted message.

Oddly enough, using Skysweeper and Hoka on the same signal with different radios and computers will result in different garbled characters. Must be something with the algorithms used in the programs.

Hoka will work on weaker signals, but then you see just the raw data stream. Skysweeper needs to have a fairly decent signal and is a little touchy on hitting the exact freq for the decoder to work.

There have been some bugs and fixes with a couple of modes using Skysweeper. It's okay for what it does and I use it for several modes.

I have a friend that has Hoka and we have a blast using it. Not at all in what I expected for the money spent, but very capable on many different modes. Would I buy it, no, its too expensive. I can't even get a bootleg copy from him.

MARS mentioned uses a multi-FSK 16 (16 tone) signal that sounds cool.

prcguy · #12 (**permalink**) 06-20-2008, 10:32 AM

Aah, ok. I have several Harris HF transceivers with built in MIL-STD 188-110 39 Tone Modems and MIL-STD-188-141 ALE but no other applications to run for decoding messages.
prcguy

Quote:

Originally Posted by blantonl

No No No... MIL-STD 188-110 39 Tone Modems... not MIL-STD-188-141 ALE.

I'm very familiar with PC ALE ;-)