teletype ?

[merlin]

I have been catching a lot of teletype, just wondering what the shift really is. For eons, it was 800 Hz but seems it is a bit wider ??

 

[ka3jjz]

What is the frequency? There isn't a lot of Baudot on HF anymore, apart from some ham use and 3 or 4 stations that are known to use it. More likely you are hearing a STANAG signal. Check it against the listings in the UDXF.

Mike

 

[dlwtrunked]

I have been catching a lot of teletype, just wondering what the shift really is. For eons, it was 800 Hz but seems it is a bit wider ??

Your filter are probably better.

 

[nd5y]

I have been catching a lot of teletype, just wondering what the shift really is. For eons, it was 800 Hz but seems it is a bit wider ??

It was 850 Hz shift for most commercial and military. A few used 425 and 170. Hams almost always use 170 Hz shift. If it's wider than 850 it's probably not RTTY.

 

[ka3jjz]

If the shift was around 200hz wide it is likely T600, a Russian mode. But you mentioned that the shift seemed wider than 800hz, so STANAG - a mode used by NATO and almost always encrypted, unless they are running a test tape - is a likely candidate. We need the frequency to be sure.

Mike

 

[dlwtrunked]

If the shift was around 200hz wide it is likely T600, a Russian mode. But you mentioned that the shift seemed wider than 800hz, so STANAG - a mode used by NATO and almost always encrypted, unless they are running a test tape - is a likely candidate. We need the frequency to be sure.

Mike

But that should not sound like teletype to him.

 

[dlwtrunked]

If the shift was around 200hz wide it is likely T600, a Russian mode. But you mentioned that the shift seemed wider than 800hz, so STANAG - a mode used by NATO and almost always encrypted, unless they are running a test tape - is a likely candidate. We need the frequency to be sure.

Mike

If the shift was around 200hz wide it is likely T600, a Russian mode. But you mentioned that the shift seemed wider than 800hz, so STANAG - a mode used by NATO and almost always encrypted, unless they are running a test tape - is a likely candidate. We need the frequency to be sure.

Mike

He needs to give us a frequency. Note that T600 (or "the Bee") stations can use either 200 Hz or 250 Hz. (On VLF they use 75Hz.) I suspect he is listening to 850 Hz shift but with better filters today as he tunes, the shifts may seem farther apart.

 

[merlin]

Well, I did overlook STANAG and TELEX. there were quite a few frequencies between 6 and 10 MHz.
I wasn't piping to decoders so didn't log any details.
I just got my long wire back up, so just seeing whats out there.

 

[merlin]

Your filter are probably better.

I have a full compliment of filters in this TS-440 so very decent in different modes.

 

[merlin]

But that should not sound like teletype to him.

It did sound like wide teletype but a fast baud rate, over 100 WPM.

 

[Boombox]

Could you list few frequencies where you've heard this?

 

[merlin]

I connected my Airspy and grabbed one of these signals.
SigIDwiki IDs this as stanag 4285
Depending on time/day, there is at least one strong signal, the other day was like a dozen between 5 and 14 MHz

 

[ka3jjz]

Recent logs show NSS Davidsonville Md. usually running STANAG 4481, but they could have changed protocol. Recently on 6487...close enough. Nonetheless it's unreadable unless you catch them running a test tape in the clear.

Well what do you know - this frequency shows up here...

Undecodeable NATO Digital Signals - The RadioReference Wiki

wiki.radioreference.com

STANAG 4285 and 4481 signals are very common - and they can be found just about anywhere on HF. All has to do with NATO

Mike

 

[db_gain]

S4285 is (typically) a 8PSK sig around 2.4KHz wide with a 2400Bd symbol rate where S4481 is BFSK or BPSK, has an 850Hz shift and 50Hz or 75Hz Baudrate. Both modes are almost always encrypted via a KG device offline, that said there are still some S4285 bcasts in the clear. Most of these emissions will be navy meaning fleet bcasts. Our subs still listen to fsk.

 

[merlin]

Well, it is not Stanag, it is teletype with 850 Hz shift. a non standard baud rate, no standard CR, just constant data.
Both multi psk and Fldigi, what it decodes is nonsensical gibberish.
I could duplicate the signal with a PN generator X-Nored to data, encrypted, very likely. Military, very likely.

 

[dlwtrunked]

Well, it is not Stanag, it is teletype with 850 Hz shift. a non standard baud rate, no standard CR, just constant data.
Both multi psk and Fldigi, what it decodes is nonsensical gibberish.
I could duplicate the signal with a PN generator X-Nored to data, encrypted, very likely. Military, very likely.

Monitored here at usual 75 Bd. The encryption will not show any CR, or any control characters, and no start or stop bits will appear to even let you determine individual characters.