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A ghostly radio station that no one claims to run

bbc.com

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Re: A ghostly radio station that no one claims to run

#51

Post by TheRealEdAbbey »

lb1lf wrote: post #43
vvanders wrote: post #37

Earlier quoted context omitted.

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. [edit] 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 wr…

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.

Re: A ghostly radio station that no one claims to run

#52

Post by Lagged2Death »

sillysaurus3 wrote: post #39
jankotek wrote: post #36

> 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. Nice explanation.

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.

The name "shortwave" is ill-considered and misleading but there's no changing it now.

Re: A ghostly radio station that no one claims to run

#53

Post by DiabloD3 »

jankotek wrote: post #40
sillysaurus3 wrote: post #39

Earlier quoted context omitted.

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.

No, it is not. The worst shortwave explanation I ever read. From BBC!

The irony is the BBC operates the best (and maybe only major commercial) shortwave stations in the world, as part of their AM radio service.

Re: A ghostly radio station that no one claims to run

#54

Post by Lagged2Death »

wichert wrote: post #5

For the lazy who were hoping to find an audio clip in the article: you can find some here: http://www.sigidwiki.com/wiki/The_Buzzer_(ZhUOZ_MDZhB_UZB76)

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.

Re: A ghostly radio station that no one claims to run

#55

Post by simmons »

criddell wrote: post #4

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 se…

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.

Re: A ghostly radio station that no one claims to run

#56

Post by vvanders »

lb1lf wrote: post #43
vvanders wrote: post #37

Earlier quoted context omitted.

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. [edit] 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 wr…

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.

Re: A ghostly radio station that no one claims to run

#57

Post by tmearnest »

sillysaurus3 wrote: post #39
jankotek wrote: post #36

> 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. Nice explanation.

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.

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.

It's a really old term...

Re: A ghostly radio station that no one claims to run

#60

Post by [deleted] »

tmearnest wrote: post #57
sillysaurus3 wrote: post #39

Earlier quoted context omitted.

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.

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. It's a really old term...

[deleted]
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