VK Logger Ham Radio Forum Archive

Any ideas on this one, having recently set up some antennas at my QTH, I have been listening around the bands, as one does.

This evening (2011-03-12) at approximately 17.00 local time I heard what sounded like a radar operating at approximately 28.300 centre frequency, with a bandwidth, from what I could make out, approx 50 kHz. It soulded like a rapid hammering sound, and seemed to have peaks every 5 kHz or so.

Between 20.30 and 21.00 local (QLD) time, I heard a similar sounding transmission centred around 28.440 MHz, again, approx 50 kHz bandwidth, but with slightly different pulse-like sound.

The transmission which suffered some degree of fading, was audible also at the QTH of Quentin, VK4AQF, approx 5 km away from my QTH, so it isn't local to my QTH. Quentin observed the same fading that I observed.
Also, at 21.00, the transmission abruptly ceased on 28.440, and tuning around the band, I found that it had moved to 29.037 MHz approximate centre.
Same transmission on both frequencies.


Any ideas on this one?

That will be the ZC4 radar from the british sovereign military base on cypress.

I have heard that as high as 34.9 mhz at full scale.

That has been around on the bands for about 25 years? maybe more.

during the first iraq war it was very very active, also in 2003 when the yanks went in.

cheers graham vk6six

Looks the same as I see from the Akrotiri radar (British RAF base in Cyprus as previous poster says) which plagues 30m now and again.

73 - Rob VK2GOM / G0MOH

Thanks to all who have replied and cleared that one up.

I wasn't sure if it was some sort of Amateur radar experiment or OHR.

It sure was strong and very consistant with no deep QSB. This thing must cause havoc to many users of the HF and low VHF spectrum, do they just operate it on any frequency where every they like?

Hello Tim,

VK4TIM wrote:Thanks to all who have replied and cleared that one up.

I wasn't sure if it was some sort of Amateur radar experiment or OHR. It sure was strong and very consistant with no deep QSB. This thing must cause havoc to many users of the HF and low VHF spectrum, do they just operate it on any frequency where every they like?

The OTHR's in Australia (and many other places), have two differing transmitter components, the first and some times the most annoying is the frequency Management & prediction systems (FMS), these are designed to suplement the swept HF sounders (also part of the FMS) to assess the doppler smearing or distortion that is present at different frequencies (which a sounder does not do very well). These systems hunt though the HF and low VHF spectrun running a mini version of the main RADAR's modulation scheme and then give a report back to the operators as to which band of frequencies are the best for them to use. By their nature they appear all over the place and some times have no "forbiden frequencies" like the main systems do.

I find my self looking for them on HF these days (ex OTHR worker) and speculate which location they are from by their modulation schemes

One thing to keep in mind, is that these systems will seek to go as high in frequency as they can to get away from the doppler distortion that occurs at lower frequencies, which allows them to track targets with greater confidence and less background noise. So bands above and below 28MHz will become their hunting grounds once the MUF rises during the cycle.

Regards,

Back in the 80's, the Russian 'Woodpecker' OTHR was a very annoying regular on the HF bands. It could sometimes take out big chunks of a band. The difference between it and, say Jindalee, was huge.

And this is the site the Woodpecker came from. I remember the Woodpecker transmissions well! Very loud in the UK.

73 - Rob VK2GOM / G0MOH

To offer some perspective, that array is at least 150m high!

I seem to recall it being possible to move the Woodpecker - Morse letter "E" sent @ 30 wpm?

I recall there was an article in AR or ARA that talked about the success some ops had with transmitting recordings of the woodpecker. Reading about it this morning I believe the transmission was more than simple pulsing.

Send them a card and see if they reply!

Wayne VK4WDN

Stumbled across this!
Follow our two Russian guides, and have a look through the old "Woodpecker" array in the Chernobyl area.
(Commentary is mainly in English)



What a ghost town this installation is now!

Is that a geiger counter we can hear around 4:20 in?

If the 10 mtr radar was on the high-pitched side, with a two-speed gearbox, it is a relatively new Iranian radar. VK Intruder Watch actually broke the case on that one - nobody else believed us. You'll find when it is strong, that it is much wider that 50 kHz - try 450 kHz!!!

If it was the older, slower 33-68 PPS radar, it could be coming from anywhere.

Regards
John VK4TJ - one of several contributors to VK Intruder Watch....

The radar signal was S9 at my QTH yesterday at 09:55UTC. Band width 28.450 to 28.490MHz. Excuse the poor screen shot, I was tuning the VFO several times.

sound

VK4GHZ wrote:Stumbled across this!
Follow our two Russian guides, and have a look through the old "Woodpecker" array in the Chernobyl area.
(Commentary is mainly in English)



What a ghost town this installation is now!

Is that a geiger counter we can hear around 4:20 in?

Excellent choice of videos Adam, thanks for the link!

Cheers
Tony
VK2TS