A few years back some brave souls visited the site of the old transmitter at Povarovo and posted some pictures and video of the trip: http://bydunai.livejournal.com/749.html
What a dreadful noise! I wonder if there's a good reason so much cold-war detritus is so ominous, so foreboding, and so nerve-wracking in its design, character and presence.
Maybe there are practical reasons in this case; maybe the sound is memorable, or recognizable even with marginal reception, etc.
This site is really cool. Thanks for sharing though I'm afraid I'll be wasting quite some time today playing around with it :)
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It looks like the site doesn't get such a large number of people very often and the CPU load is getting too high to hear anything clearly. For clearer audio of the buzzer check here:
I read this article last weekend and after reading it, I put batteries in my shortwave radio to see what was out there. Turns out, there's pretty much nothing.
I couldn't hear anything on 4625 kHz. I let my receiver scan and when it was done I checked out what it detected and found absolutely nothing interesting. The most powerful signals were Christian broadcasts that had a kind of doomsday feeling about them.
It seems like there's a lot of underutilized spectrum.
Night hours are best for shortwave reception. You could also need an external antenna depending on how far you are listening from. Another problem, probably the biggest one today, which affects reception on these frequencies (and generally on the HF bands) is the radio noise generated by many bad designed switching power supplies and appliances. Switching regulators (power supplies, converters, chargers etc.) for efficiency and size reasons have moved from the tens of KHz through the hundreds of KHz and recently they started working above 1 MHz which means having into our homes one or more transmitters with antennas (mains or output cable) that if not properly designed, filtered and shielded will render reception on HF bands next to impossible.
The shortwave frequencies still feel very underutilized. When I scan the FM (88 - 108 MHz) and AM (540-1600 kHz) radio frequencies, I pick up a lot of stuff. The shortwave band is relatively vast and feels very sparse. Considering how valuable spectrum is these days, it's hard to believe that we couldn't find a better use for it. Is it because it is so prone to noise that it's less valuable?
The wavelength at these frequencies is very long, meaning antennas must be very large. In addition, the bandwidth is very small -- you can't exactly encode data on these frequencies for any practical purpose (some digital modes are popular on ham radio bands; e.g. PSK31, RTTY, etc.)
Yep, PSK31 has a baud rate of 31.25 - that's literally 31 bits per second. There's no practical use for that in modern commercial or consumer applications.
In amateur bands, symbol rate below 28 MHz is limited to 300 baud.
And anything in the 2M band is also symbol rate limited(I want to say it was 1200baud but I could be wrong).
It's really frustrating if you want to do any development with digital modes.
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Looked it up, it's a 19.6k symbol rate limit(rather than leave it open and restrict bandwidth). You can carry a ton of data on 2M if you wanted but legally you can't exceed the speed of an old dial up modem.
Are US ham bands really symbol rate (rather than bandwidth)limited?
Here in LA (Norway, for the ham prefix challenged), we can modulate in whatever way we feel like on 2M, as long as the signal bandwidth does not exceed 18kHz.
(So, using a clever modulation scheme, you could get very close to the Shannon limit for the given channel bandwidth and noise level - assuming a very healthy 30dB S/N, one should be able to wring approx. 180kbps from an 18kHz channel. (Granted, in the real world with filters without infinitely steep skirts we'd get nowhere near this - but, let's say you could get 1/3 or so without trying too hard.)
It's actually both, 20Khz bandwidth and the 19.6k symbol rate.
I love amateur radio but at least on the 2m bands it's mostly dominated by people just chatting on repeaters with others they already know or dead quiet. I monitor 146.52(our calling frequence) on my ~300mi weekly trip and I've made only one contact in 2 years.
APRS is pretty dead, there's a ton of interesting stuff that could be done on the ECC and symbol rate front but no one really seems interested. Not much has changed on the spec for a long time. Compared to some other countries where they have some very robust and flourishing 2m digital modes it's a shame.
Essentially, yes. My guess is that it's due to the fact that amateur radio for a long time has been CW and SSB, where there isn't much bandwidth issue. Digital modes are the new kid on the block (especially considering the average age of US hams is probably quite high), so rather than addressing the root issue, they decided just to target that new kid.
There are bandwidth restrictions on the 60m band, where amateur radio is secondary.
There is more than one shortwave band, some are more useful than others and there are fairly large gaps between them, so it would feel sparse even if there were a lot of stations: https://en.wikipedia.org/wiki/Shortwave_bands
But as others have said, in many parts of the world there aren't many shortwave stations left. Africa and parts of Asia still have quite a few however.
If you are looking at xray penetration in the atmosphere, it is very opaque. Almost no xrays get through hence why space telescopes are needed to do xray astronomy.
As others have mentioned, the time of day may have effected reception of the 4625 kHz station.
However, in general, I've noticed that there seems to be far fewer stations received on the shortwave band these days, compared to the 1980's when I listened to shortwave a lot as a kid. I think this is because I'm using a low-end receiver with its built-in telescopic antenna instead of a more sophisticated SWL setup with a proper antenna. Broadcasters such as the BBC World Service target specific geographies with their transmissions so they can be received on a low-end radio, and they no longer bother targeting developed regions such as North America with these transmissions. I'm guessing if I used the same radio somewhere like Africa, I'd be able to pick up a lot more stations.
> It seems like there's a lot of underutilized spectrum.
There's some good reasons for this. HF is pretty challenging to fully utilize.
You have propagation that varies between "worldwide" (so it's difficult to assign new bands without ITU involvement), and "sunspot" (so you better have a plan B). And these variations aren't just over the duration of a sunspot cycle, but also over the day/night cycle.
eg, for maritime use, we have channel clusters at 2, 4, 6, 8, 12 and 16MHz. Which to use depends on the time of day the distance to the other station, and how much the sunspot cycle is messing with your first choice. Fun!
Then the physical challenges that arise from the ideal antenna length being proportional to the length of the wave. At 2.4GHz the challenge is precisely cutting your quarter-wave antenna to a fraction of a mm (31.25mm). At 2.4MHz same challenge becomes finding space for a 31.25m (~100feet) antenna.
Another big consideration is that these frequencies aren't particularly friendly to high-speed digital use. I suspect this is related to Nyquist theorem - the fewer waves you're receiving per second, the fewer symbols per second can be encoded into them.
And finally, some rather difficult legacy users. Aviation and Marine users who consider their usage life-or-death, radio amateurs that likely do too (heh), radio-navigation (I was reading about Loran making a comeback recently, to provide some backup when GPS is manipulated), over-the-horizon radar (which can be a lot like sharing a telephone call with a foghorn), etc.
All this taking up about as much bandwidth as one wifi channel ..
As the article says, just because you couldn't hear it the one time you tried, doesn't mean it isn't transmitting. You hearing it depends on the condition of the ionosphere. The time of day, the number of sunspots along with other things will effect your reception of the signal.
From what I understand it isn't on all the time. There are actually long periods of time where it doesn't transmit anything. Last week when I was digging a little deeper I ran into an older discussion on another board where they were saying it was off for years and came back on when Russia invaded Ukraine.
Were you in a good spot? I can hear a lot of stuff with my shortwave receiver and I'm in SLC, Utah. Occasionally, I get to hear pirate transmissions and whatnot.
"pirate transmissions" I am surprised. Only a month ago I met a guy who (as an "art project") has actually started to transmit on the shortwave. Bought an old army radio and was now jumping all over the country with the installation and transmitting... well, arty stuff. He claimed he got responses every now and then, now I think he might be right.
Is that a thing? I bailed out of the radio waves 30 years ago when I got access to data links...
> the Buzzer operates at a relatively low frequency known as “shortwave”. This means that – compared to local radio, mobile phone and television signals – fewer waves pass through a single point every second. It also means they can travel a lot further.
Is it? If you imagine a fixed point in space, a short wave would mean more waves pass through it every second, not less. Short waves have more energy (they have bounce up and down more quickly) which allows them to travel further.
It's true that "shorter" waves would mean higher frequency, but "shortware" radio uses longer (lower-frequency) waves, relative to most other modern radio systems, so it is true that "fewer waves pass through a single point every second".
Also, it is true that for a given amplitude, a higher frequency wave does contain more energy, but typically, higher frequency waves don't travel as far. Shortwave radio travels particularly far because they happen to be in the right frequency to bounce off the ionosphere, which allows them to travel further than line of sight.
Shortwave, as in short with respect to "mediumwave" transmissions, like regular old broadcast AM radio, or "longwave" which can be used to communicate with submerged submarines.
IIRC, subs use ELF or ULF. My understanding is that some of the older subs could trail a long wire antenna behind them.
It'd seem to me that the bandwidth for such would be abysmal.
Is this correct? I did take some EE courses but that was like forty years ago. All I have ever done with that is receive. I should probably learn more.
It's shortwave (1.6MHz - 30MHz) and not "shorter wave". Radio and TV commonly use FM or UHF (300MHz upwards). So the explanation is technically correct: more waves pass a given point in space.
Most of the actual radio transmitters are no longer operated directly by the BBC. As far as I know the only site still under their operation is BBC World Service Atlantic Relay Station on Ascension Island.
Whilst the BBC still produces the radio and TV programme content, in the UK the radio and TV transmitters are operated by Arqiva and World Service shortwave by Babcock.
I was lucky enough to work on one of the last remaining operational high power longwave AM radio transmitters in the UK at Droitwich Transmitting Station. BBC Radio 4 longwave is broadcast at 500kW on 198kHz (locked to a HP 5065 Rubidium standard) and can be received in large parts of western europe.
What's to stop an adversary from broadcasting the same tone on the same frequency and overpowering the signal in certain areas? It strikes me that if the conjecture (of it being a reserved frequency for war time command signals) is correct, it would be relatively easy to break. Perhaps the weekly random words are some kind of authentication mechanism, but that seems like a long time to have to wait to authenticate the signal.
It sounds from the article they likely do know where the antennas are based?
If not, is it possible to use direction finding to obtain the location of antennas propagating shortwave frequencies?
(I assume this is more difficult due to the use of the ionosphere)
Also is there any remote chance the hardware attached to the aerial (power amps etc) could pick up unwanted RF or other interesting electrical interference and re-broadcast it, which may give some useful information.
It reminds me of a number station because the article had a long section talking about numbers stations, and speculating on where "the Buzzer" fits in, given the assumed typical uses for those stations.
It is a numbers station. It's been known for years as the article says, and referred to as a (one of the many) numbers stations. Many/most don't actually read numbers.
As mentioned in the below comment, the author buried the probable lede: most of the time transmission is a placeholder to discourage others from using the band. During exceptional circumstances (as defined by the station's operator), it will transmit coded messages to global/regional operatives. E.g., to coordinate espionage when conventional communications are offline.
That constant sound is also useful for the spies. Without that it would be hard to know you have tuned on the right frequency (I'd assume they would use some pretty simple and low tech radios).
