[GreenKeys] Teletype on 4.004 Revisted

[John Vendely]

I did DF the 5339 kc station a few years ago, though not with great 
precision, and I don't recall the exact bearing.  However, the signal I 
heard at that time was coming from southeast of my QTH on the Space 
Coast of Florida (Brevard County, about 35 mi. south of Cape 
Canaveral).  I didn't have any lines of bearing from any other locations 
with which to triangulate, but that one LOB might suggest a location in 
Mexico. I can recall only that the LOB was too far to the south to be 
coming from within the U.S. unless it was on the southern Gulf coast of 
Florida.

It's true that for decades, the U.S. Navy had several HF transmitter 
sites transmitting the Fleet Broadcasts on numerous frequencies to 
various sectors of the world, and that these persisted as backups long 
after the Fleet Broadcast had gone to satcom.  Perhaps some still 
exist.  However, the U.S. Navy HF broadcasts were 75 baud, and this 
station appears to be 50 baud.

I could get an approximate LOB on the 14373.5 transmitter mentioned in 
one of the posts, using the log periodic here.  If 4004, 5339, and 
14373.5 are indeed all carrying the same data, as suggested, this  might 
shed some light on things.  I don't currently have anything capable of 
taking a decent bearing on the 4 and 5 Mc frequencies.

Regarding the earlier posts mentioning older encryption gear like the 
KG-84, some of these systems are still in use, in some cases in 
modernized form.  For example, the Harris PRC-117G VHF/UHF manpack 
transceiver contains a few of the older encryption systems, including 
KG-84B.  These crypto units, once chunky pieces of standalone hardware, 
can now be contained in a small section of an FPGA inside a modern 
software-defined radio.

There's little point in attempting to decode any of this stuff. However, 
some, like the old KW-7 and the KG-84, have an easily identifiable sync 
sequence.  Such systems can be identified if the system occasionally 
re-syncs, but unless you have NSA-like capabilities, you're not going to 
get anything decodable out of these transmissions.  Upon rare occasion, 
however, some stations run test sequences in the clear for 
troubleshooting purposes, and if you're really patient and willing to 
collect huge quantities of data, these can sometimes be observed.

73,

John K9WT

On 11/24/2013 11:37 PM, epvgk at limpoc.com wrote:
> On Sun, Nov 24, 2013 at 10:22:18PM -0600, Ron Kolarik wrote:
>> The mystery signal is also on 5339kHz. I've got it running in 2 panadapter windows
>> and they are identical. 4004 is S-9+10  5339 is S-9+. The loop isn't up for the winter
>> so no null/peak possible with the current antenna. I'm in Nebraska. 0419z
>>
>> The hardware is most like "glass" TTY and not mechanical. This looks a lot like
>> the encrypted stuff that used to reside on the 30m band. Someone told me that
>> one was NAVY from Maine I think.
>>
>> Ron
>> K0IDT
> I think from reading about this stuff a while back that these 850Hz shift FSK signals
> (and there seem to be lots of them on HF) are encoded using a protocol called
> STANAG 4481 FSK. The datastream is apparently encrypted with KG-84 encryption equipment.
> http://en.wikipedia.org/wiki/KG-84
>
> eric
>
>>    ----- Original Message -----
>>    From: Larry
>>    To: greenkeys at mailman.qth.net
>>    Sent: Sunday, November 24, 2013 7:14 PM
>>    Subject: Re: [GreenKeys] Teletype on 4.004 Revisted
>>
>>
>>    On 11/24/2013 6:10 PM, Charles Ring wrote:
>>
>>      To me the interesting part is that this signal has been there, completely unchanged, since 1968 or probably earlier. Same speed, same shift, same every observable characteristic. This, long after the original hardware would have become unrepairable from lack of parts and/or people with the needed skills.
>>
>>
>>
>>
>>      On 11/24/2013 1918, Duncan Brown wrote:
>>
>>        it is strong in upstate NY also.  I can hear it in the house on a portable with the whip down all the way.
>>
>>        Maybe we need to set up a DF net.  Anyone have an AN/PRD-1??
>>
>>        Duncan
>>        USASA 31J
>>
>>
>>        On 24-Nov-13 18:41, NNN7DXB at aol.com wrote:
>>