Up until a few months ago, listening to the BBC was a haphazard, sometimes impossible task for me. There were basically two options open to me: one possibility was to get into the car and drive in the general direction of England and hope to pick up Radio 4 on the long wave. Curiously enough, reception on our old Renault 16 was much better than in any car (or on any radio) since then. Even so it was never an ideal solution.
The other option was to try and pick up the World Service on short wave or medium wave. Short wave was far too painstaking and in any case I was always having to change from one frequency to another. I eventually settled on 648 on the medium wave as the best of a poor bunch, but even this choice was beset with difficulties. For one thing reception would often fade and the BBC would be replaced by some state-sponsored station from behind the Iron curtain where the fare consisted of Bulgarian folk music or talk of "freedom-loving peoples" and "capitalist hyenas". Post 1989, the problem remained although the content of the interloping programmes changed.
Another problem with the medium wave is that, like Dracula, it only comes into its own during the hours of darkness.
All this has changed now that I have easy access to the BBC via the Internet. I have noticed something rather strange, though. The live web programme lags five to ten seconds behind the identical live programme broadcast on FM. Can anyone explain this phenomenon?
I consulted the oracle, East Anglian branch.
ReplyDeleteDigital signals go up to satellite and back, while the terrestial stuff goes round inside the atmosphere.
Digital receivers have to process the signal and turn it back into sounds which apparently varies.
Am prepared to bet the house that you weren't expecting to be informed from this source!
I am prepared to bow to the oracle's superior wisdom (for a fee or a takaeway from the fish and chip shop from across the way).
ReplyDeletePerhaps this also explains why reception, on the World Service at any rate, is on occasion slightly "garbled" or speeded up, at other times goes back and repeats a couple of sentences or so. Care to put this to the oracle?
Living as we do in the far reaches of the NW coast of Scotland it is frequently the case that neither VHF nor MW can be received - but Long Wave is usually pretty good (even in the glens).
ReplyDeleteBUT there are occasions when our listening is completely wrecked by CRICKET !!
Cricket and other sports should have their own frequencies and so allow the serious listener to get down to some serious listening.
PS
Heaven help us in Highland Region from digital radio!
You mean cricket doesn't come under the heading of "serious listening"?
ReplyDeleteBarnaby, let me add: it's called 'Propagation Delay'. Cribbing from wikipedia:
ReplyDelete"...propagation delay is the amount of time it takes for the head of the signal to travel from the sender to the receiver over a medium. It can be computed as the ratio between the link length and the propagation speed over the specific medium.
"Propagation delay = d/s where d is the distance and s is the wave propagation speed. In wireless communication, s=c, i.e. the speed of light. In copper wire, the speed s generally ranges from .59 to .77."
http://en.wikipedia.org/wiki/Propagation_delay
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Your radio receives wireless at the speed of light; the internet is slower because at least part of it uses copper wire.
If you had fiber optic cable direct from source to your receiver you'd theoretically receive at the speed of light. In practice it's a tad slower, but faster than copper.
-lesle
Many thanks, lesle. What you said about the use of copper wire is fascinating. I would never have thought of that. I suppose the bottom line is that if you want to set your watch by the radio, you had better not use the Internet?
ReplyDelete