Transmission on SW...what is this? - UK Vintage Radio Repair and Restoration Discussion Forum

sexton_mallard · 10th Oct 2020, 10:24 am

There are several of these transmissions across the SW bands which have been running for years and I have no idea what they are. I thinking possibly Radio Mondale or radar. They all have the same whirring noise suggesting a common format or protocol. Here is a link to a short YouTube video of this noise at around 41m.

https://youtu.be/iyOvxIkMsw0

turretslug · 10th Oct 2020, 10:33 am

That sounds rather like a facsimile (fax) transmission- I think the periodicity of the whirring is framing pulses, the regularity is implicit of a test pattern or ident (perhaps!). The HF bands used to be alive with these signals outside the regular amateur and broadcast bands. Maybe the fact that I'm surprised at other people's puzzlement is starting to betray my age....

Used to be used by the likes of news agencies to transmit pictures, also for things like weather information.

Radio Wrangler · 10th Oct 2020, 11:00 am

Hellschreiber?

David

g4aaw pete · 10th Oct 2020, 12:18 pm

High speed RTTY - possibly military.

Andrew2 · 10th Oct 2020, 12:59 pm

I reckon Pete is right, it's probably 'stanag 4285' or similar, a fast RTTY mode. Decoders are downloadable for free ont' t'internet. You'll need a receiver capable of SSB reception.

trh01uk · 10th Oct 2020, 1:24 pm

I've been hearing stuff like this since I started on the SW bands in the late 60s. Never thought to ask exactly what it is - just another one of those "noises" that seem to have been on the bands forever.

However Andrew2's suggestion of "Stanag 4285" seems probably right - given it sounds much like this example: https://www.youtube.com/watch?v=u-CgZNJIAVs

Richard

sexton_mallard · 10th Oct 2020, 7:55 pm

Thanks! Seems the mystery is somewhat solved. NATO STANAG 4285 it must be then. Here is another recording from my Bush BS35 domestic radio in which two or more sources appear to transmit two bursts then pause for the next transmission in a cycle. The transmitters appear to be at different distances. Please ignore the continuous PLC adaptor put-put-put and ticking clock in the background.

https://youtu.be/D36XA3h6cKE

10th Oct 2020, 8:47 pm

My favorite data sound is piccolo https://www.sigidwiki.com/wiki/Piccolo still used upon occasion by amateurs for fun.

stitch1 · 10th Oct 2020, 8:47 pm

Reminds me of when I worked a RAF Brampton HF RX station, our job was to monitor HF RTTY transmissions from places like Belize, Cyprus and Hong Kong. Mostly done by ear, if the reception was deteriorating we used the RA17s to find a suitable frequency then message the far end to ask them to change frequency. We’d then retune the Marconi MST rx’ers and wait for it to come up. We had to colour a chart in for each station, green or red in 15 min segments.
If you weren’t concentrating or fell asleep! It was easy to loose contact.
It’s not me on the photo, probably taken in 1980.
Happy days.

John

10th Oct 2020, 10:24 am	#1
sexton_mallard Heptode Join Date: Sep 2013 Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland. Posts: 501	Transmission on SW...what is this? There are several of these transmissions across the SW bands which have been running for years and I have no idea what they are. I thinking possibly Radio Mondale or radar. They all have the same whirring noise suggesting a common format or protocol. Here is a link to a short YouTube video of this noise at around 41m. https://youtu.be/iyOvxIkMsw0 __________________ Dom Less snakes...more ladders!

10th Oct 2020, 10:33 am	#2
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,396	Re: Transmission on SW...what is this? That sounds rather like a facsimile (fax) transmission- I think the periodicity of the whirring is framing pulses, the regularity is implicit of a test pattern or ident (perhaps!). The HF bands used to be alive with these signals outside the regular amateur and broadcast bands. Maybe the fact that I'm surprised at other people's puzzlement is starting to betray my age.... Used to be used by the likes of news agencies to transmit pictures, also for things like weather information.

10th Oct 2020, 11:00 am	#3
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,876	Re: Transmission on SW...what is this? Hellschreiber? David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

10th Oct 2020, 12:18 pm	#4
g4aaw pete Heptode Join Date: Jan 2008 Location: Birchington Kent, UK. Posts: 596	Re: Transmission on SW...what is this? High speed RTTY - possibly military. __________________ Regards Pete

10th Oct 2020, 12:59 pm	#5
Andrew2 Nonode Join Date: Mar 2010 Location: Dukinfield, Cheshire, UK. Posts: 2,037	Re: Transmission on SW...what is this? I reckon Pete is right, it's probably 'stanag 4285' or similar, a fast RTTY mode. Decoders are downloadable for free ont' t'internet. You'll need a receiver capable of SSB reception. __________________ Andy G1HBE.

10th Oct 2020, 1:24 pm	#6
trh01uk Octode Join Date: Nov 2010 Location: Ross-on-Wye, Herefordshire, UK. Posts: 1,654	Re: Transmission on SW...what is this? I've been hearing stuff like this since I started on the SW bands in the late 60s. Never thought to ask exactly what it is - just another one of those "noises" that seem to have been on the bands forever. However Andrew2's suggestion of "Stanag 4285" seems probably right - given it sounds much like this example: https://www.youtube.com/watch?v=u-CgZNJIAVs Richard

10th Oct 2020, 7:55 pm	#7
sexton_mallard Heptode Join Date: Sep 2013 Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland. Posts: 501	Re: Transmission on SW...what is this? Thanks! Seems the mystery is somewhat solved. NATO STANAG 4285 it must be then. Here is another recording from my Bush BS35 domestic radio in which two or more sources appear to transmit two bursts then pause for the next transmission in a cycle. The transmitters appear to be at different distances. Please ignore the continuous PLC adaptor put-put-put and ticking clock in the background. https://youtu.be/D36XA3h6cKE __________________ Dom Less snakes...more ladders!

10th Oct 2020, 8:47 pm	#8
Guest Guest Posts: n/a	Re: Transmission on SW...what is this? My favorite data sound is piccolo https://www.sigidwiki.com/wiki/Piccolo still used upon occasion by amateurs for fun.

10th Oct 2020, 8:47 pm	#9
stitch1 Heptode Join Date: Jan 2008 Location: Durham, County Durham, UK. Posts: 826	Re: Transmission on SW...what is this? Reminds me of when I worked a RAF Brampton HF RX station, our job was to monitor HF RTTY transmissions from places like Belize, Cyprus and Hong Kong. Mostly done by ear, if the reception was deteriorating we used the RA17s to find a suitable frequency then message the far end to ask them to change frequency. We’d then retune the Marconi MST rx’ers and wait for it to come up. We had to colour a chart in for each station, green or red in 15 min segments. If you weren’t concentrating or fell asleep! It was easy to loose contact. It’s not me on the photo, probably taken in 1980. Happy days. John Attached Thumbnails