10430 AM

[Marcy57]

Seems to be a vy strong S9 AM carrier here lately
....73,s Marcy

 

[sprman1955]

Have heard a numbers station on there befor around noon time cst here in TN.Very strong signals !

 

[Token]

Have heard a numbers station on there befor around noon time cst here in TN.Very strong signals !

Are you sure you heard this numbers station on 10430 kHz at aorund 1200 CST? HM01 (the only numbers station that should regularly hit your area with a strong signal) has an 1800 UTC (1200 CST) schedule on 11635 kHz, before noon CST< or in the 1700 - 1800 UTC time period, it should be on 11530 kHz. It has a 1600 UTC sched on 11435, and a 0600 UTC sched on 10345, all similar numbers in the frequency. But I don't remember it (HM01) having any schedules these days on 10430 kHz.

HM01 is, of course, well known for errors, transmitting on the wrong frequency or at the wrong time. And occasionally they change schedules. I ask if you are sure about the 10430 kHz frequency because if this has become a regular thing the online scheds for HM01 might be behind the times, and may need to be brought up to date.


To the OP, 10430 used (no idea if it still is or not) to be used by US Navy for STANAG 4481 FSK. If you caught it resting, or it was broken, there would be a single tone, like a carrier.

T!

 

[jwt873]

Just tuned in 10.430 MHz at 17:00 UTC.. There is a strong carrier there. About S9. I would have though it was a local birdie, but since others hear it, I guess not.

Will leave it on during the day and see what happens..

 

[Marcy57]

Thats what I copied I thought it was a AM carrier vy strong...Marcy

 

[jwt873]

Interesting... I left it on most of the morning. It was a pure unmodulated carrier for quite a few hours. But at 19:00 UTC, I took a look and noticed that it had turned into what sounded like very high speed RTTY. (had to switch from AM to CW to copy it). -- Sample attached below.

It's been maintaining S9 with a few fades to S5 pretty well all day..

 

[dlwtrunked]

Interesting... I left it on most of the morning. It was a pure unmodulated carrier for quite a few hours. But at 19:00 UTC, I took a look and noticed that it had turned into what sounded like very high speed RTTY. (had to switch from AM to CW to copy it). -- Sample attached below.

It's been maintaining S9 with a few fades to S5 pretty well all day..

This is good old encrypted 75 Bd USN/NATO (not high speed by any definition as such) 850 Hz shift FSK RTTY. It will sound like a dead carrier with a little noise if tuned in AM as it should.

I do not see a month go by where somewhere somewhere report this on some frequency as a mystery signal (This type of signal has been around for the 50 years that I have monitored.) That frequency is used by USN in Dixon, CA.

 

[jwt873]

OK.. Thanks for the ID.. Not used to hearing the 850 Hz shift. (Normal ham RTTY is 170). Out of interest, it's well after dark here and the station is still pounding away. But now, it's only S4.. Just above the noise.

And.. I did a quick Google search and found this page with some good audio files for identifying RTTY sigs.

Radio Teletype (RTTY) - Signal Identification Wiki

RTTY (Also known as Baudot or ITA2) uses the Baudot 5-bit alphabet with FSK to send text messages over the shortwave. This mode is gradually dying out in favor of more robust modes like PSK31 in the amateur service.

www.sigidwiki.com

 

[dlwtrunked]

OK.. Thanks for the ID.. Not used to hearing the 850 Hz shift. (Normal ham RTTY is 170). Out of interest, it's well after dark here and the station is still pounding away. But now, it's only S4.. Just above the noise.

And.. I did a quick Google search and found this page with some good audio files for identifying RTTY sigs.

Radio Teletype (RTTY) - Signal Identification Wiki

RTTY (Also known as Baudot or ITA2) uses the Baudot 5-bit alphabet with FSK to send text messages over the shortwave. This mode is gradually dying out in favor of more robust modes like PSK31 in the amateur service.

www.sigidwiki.com

Yes, that page is a good reference and others should look at it. For many of us who watch utilities and rarely ham stuff (I am an Extra Class), 850 Hz shift is more commonly seen than 170 Hz shift. Dixon also uses 7597 and 8694. Other similar transmissions come out of Isabella PR and the USN uses (at the Davidsonville MD USAF): 4005, 4985, 6487, 9830, 12015, and 15969.

 

[sprman1955]

Yes am very sure about the time here.I have heard it on 11.435 at 11:40am cst as well from time to time.