What is Jet XJT? I've never heard of that
The term XJT was assigned / used quite a while ago when the signal first appeared in common use. There was a couple year period of time there where hobbyist were unsure of its source or its use. Although the X designator XJT is still on the list (ENIGMA Control List,
http://www.numbersoddities.nl/ecl25 2011.pdf ), the use of the term Jet or XJT has fallen from common application. Most people now know it as STANAG 4285. However, there are other signals that sound similar, such as STANAG 4529 and certain Chinese modems. So going by sound alone it is hard to narrow down, but looking at the total signal, type of PSK, rate, bandwidth, starts to get a better ID on it.
Also, a common misconception is that all STANAG signals sound like this, and so people sometimes fall in the bad habit of just calling it STANAG. STANAG is simply a set of NATO standards, and the term STANAG, followed by a number, can apply to modems, tire sizes, bullet design, gas mask performance, etc. The term STANAG without a number following it is useless.
Here are three different common STANAG signals found in the HF spectrum and there are several more:
Link 11, also called STANAG 5511:
https://www.youtube.com/watch?v=__-rtLRQUhg
STANAG 4529, sometimes mistaken for STANAG 4285:
https://www.youtube.com/watch?v=Ite8yZxEjKI
STANAG 4285, the signal originally seen in this thread:
https://www.youtube.com/watch?v=u-CgZNJIAVs
Another commonly seen STANAG signal is STANAG 4481 FSK, I don’t happen to have an example of it up on my YouTube channel, I should probably put one up. 4481 FSK is the designator for one of the 850 Hz shift versions of RTTY found all over HF.
T!
