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 High power annoying emissions on HF band
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 Return to top of page · Post #: 1 · Written at 12:34:18 PM on 13 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

Can anyone help identify the source of powerful emissions which appear randomly on the HF band?

Clearly a man-made signal, best described as a powerful pulse/data train. Roams across the band seemingly willy-nilly threatening to melt the front end of receivers. I've heard it as low as 10MHz , others have encountered it around 27MHz.

My interest is in solar emissions between 18MHz to 22MHz but this seems smack in the middle of that rogue transmission. As I search for a 'quite spot' on the band the damn thing appears to track up and down as well, often crossing paths with me and swamping my equipment.

I have heard many stories from the 27MHz mob regarding Chinese spies and agitators but clearly this nonsense.

I am guessing it is a research project, possibly along similar lines to early HAARP emissions, maybe from one of the research bases in Antarctica studying ionospheric properties.

Whatever it is, I wish it would piss off. They have been at it for the last few years now, surely they got enough data by now.

Any ideas on the source would be welcomed, I would very much like to contact the organisation responsible.


 
 Return to top of page · Post #: 2 · Written at 2:49:40 PM on 13 December 2022.
Gandhn's Gravatar
 Location: Cameron Park, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 399

My first thought would be over-the-horizon radar, but only a guess.
No idea who you could grumble to!
Harold


 
 Return to top of page · Post #: 3 · Written at 4:45:02 PM on 13 December 2022.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2039

I listen most weekends on the HF bands and haven't encountered whatever it is that affects you.

Can you provide an audio recording (wav/mp3 file) so that I can get a better idea of what it is?


 
 Return to top of page · Post #: 4 · Written at 6:50:01 PM on 13 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

The 'over the horizon radar' thought is very plausible, especially as it roams across the band. I have it in my mind it is bounced off the ionosphere, which I guess is what we could expect for OTHR work?

I will try and record it, then I will have to learn how to format it, set up a wav/mp3 file and post it. It's high time I learnt anyway.

Meanwhile, it sounds like a rapid machine gun burst, lasts no more than 2 seconds then appears on another frequency on the band.
Belts the hell out of loudspeakers. Think of a low frequency square wave modulating the carrier at 3000% for a short burst.


 
 Return to top of page · Post #: 5 · Written at 9:11:57 PM on 13 December 2022.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2039

I might have heard something like that on 16.000 MHz a few weeks ago, but it wasn't ear-shattering. In the cold war days the Ruskies used a "woodpecker" sound for their OTHR testing, perhaps this is a newer version. If so, I doubt your complaint will accomplish anything.

Still, I'll wait for your recording.


 
 Return to top of page · Post #: 6 · Written at 10:12:25 PM on 13 December 2022.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7342

I doubt this affects you, being so far away, but Sydney has a small fleet of experimental electric route buses and every time I pass one in my car its harmonics blacks out my radio if it is on AM. I am wondering if the ACMA inspectors have run their eyes and ears over these things or not. My guess is not.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 7 · Written at 11:50:21 AM on 14 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

16MHz is right up its alley, the Russian Woodpecker is a good description. As it sweeps from 22MHz to 10MHz it seems selective to where it will dwell for approx. 2 second bursts. There are points along its sweep where it does not stop, or if it does, then at low power levels.

16MHz is likely a 'pass at low power' point on its way down to 10MHz, where it wreaks havoc briefly then starts again at the top i.e. 22MHz,
although others have experienced it at 27Mz.
I have never heard it in the 40 meter band, definitely cuts off sharply below 10MHz.

11MHz, 18MHz and 19MHz are the worst afflicted here, but that may be my crude antenna setup favouring those frequencies.

Regarding radio inspectors, or RI's as they were known in the crazy CB radio days late 70's, the government systematically began culling them in the 90's. Today are are almost extinct.


 
 Return to top of page · Post #: 8 · Written at 8:17:34 PM on 14 December 2022.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6720

Most recognised forms interference have identifying signatures.

So, to that end, what would be useful is an audio recording of the subject emissions. If you have a YouTube channel you could upload it to there and link to it here. Otherwise upload it to a document sharing site.


 
 Return to top of page · Post #: 9 · Written at 8:30:12 AM on 15 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

I have begun recording it as it appears in dribs and drabs across the band. I was wondering how to upload it to Brad after cropping it so I don't present wasteful minutes of normal noise with a 2 second burst somewhere in the middle.

I never thought of YouTube. That seems the best way to get this 'out there'.

What I hope is that if a research organisation is behind this they may have a PR officer who may offer a generic explanation of what the aim of the research is. I am more interested in learning rather than complaining.

I'll do some YouTube scouting and see what how when why and how much.


 
 Return to top of page · Post #: 10 · Written at 11:26:47 AM on 19 December 2022.
Flukeoneseventyfive's Gravatar
 Location: Laidley, QLD
 Member since 16 September 2015
 Member #: 1799
 Postcount: 114

Do you have a SDR radio you can grab a few MHz of spectrum, It may be Ionospheric Sounding transmissions.
with the waterfall display in the SDR software, you can see these transmissions just run up the bands.
A good recording would be great .


 
 Return to top of page · Post #: 11 · Written at 11:43:36 AM on 19 December 2022.
Flukeoneseventyfive's Gravatar
 Location: Laidley, QLD
 Member since 16 September 2015
 Member #: 1799
 Postcount: 114

Just for interest.
You could try some online receivers, around the world and it may give you an idea of where the transmissions are coming from.
https://www.receiverbook.de/?type=openwebrx
https://rx-tx.info/map-sdr-points
I run an openwebrx system, but it is currently down.

Also have you considered solar panel regulators, is the noise there at night ???


 
 Return to top of page · Post #: 12 · Written at 8:48:17 PM on 19 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

Ionospheric Sounding transmissions is the most likely explanation. My very crude antenna is orientated southward. I have suspected for a while now somewhere in Antarctica is the source.

I am in the process of replacing Windows with Linux, this is presenting problems with my recording medium which is Windows based.

The web receivers seem like my best option at the moment, meanwhile if you get your openwebrx back online please let me know.

Solar panel regulators not the source, they don't roam across the band methodically, I reckon you have nailed it with the ionospheric research stations. My first impressions were HAARP- like activity which of course covers OTHR.

Very inspiring comments from everyone, thank you.


 
 Return to top of page · Post #: 13 · Written at 8:30:14 PM on 20 December 2022.
BurntOutElectronics's Gravatar
 Location: Melbourne, VIC
 Member since 2 October 2019
 Member #: 2392
 Postcount: 271

I agree with the idea of seeing its sweeping characteristics with the use of a SDR receiver/spectrum analyser. It was my first thought when you mentioned it seems to swing through a range of band space.

I just came back from a trip around the Eyre peninsula with the NGT on 11MHz and 14MHz most of the time and certainly never experienced the interference you mention. So either localised to your area or the east coast somewhere.


 
 Return to top of page · Post #: 14 · Written at 9:20:48 PM on 20 December 2022.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5303

If there is a radar like there is likely at least one at Ballarat aerodrome for weather and it or something else around the place has a rotating head that would have an even separation.


 
 Return to top of page · Post #: 15 · Written at 9:11:12 AM on 21 December 2022.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 472

Yes, when I first encountered it my first impression was, and still is, a swept beam, in azimuth as well as frequency.


 
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