More frequencies have been discovered for the Tadiran radios in use by the Mexican Navy. Mike Chace-Ortiz reports that this system has actually been in use for some time.
There are also two frequencies where the older Harris AVS voice scrambler, aka the "Hooter," is still in use.
Here's the list of frequencies heard here:
4595.0 Harris AVS
4617.5 Tadiran scrambled voice
4625.0 Tadiran
4650.0 Tadiran
4675.0 Tadiran
4700.0 Tadiran
4707.0 Tadiran
4730.0 Tadiran
4810.0 Stanag 4285, continuous and message mode
4820.0 Tadiran encr 110A and 2-tone data mode
4865.0 Tadiran clear voice, then 110A
4880.0 Tadiran clear and scrambled voice
4885.0 Tadiran encr 110A & scrambled voice
4890.0 Tadiran encr 110A & clear voice
4895.0 Tadiran rekey/sync sequence and buzzy mode
4900.0 Harris AVS
4910.0 Tadiran rekey, occasional short PSK data bursts
4915.0 Tadiran selcal, no traffic
4920.0 Tadiran encr 110A
4930.0 Tadiran
Mike has heard others, as low as 3808 kHz USB, and as high as 19105. These have so far not been heard here.
