Radio 1 98.5MHz London sound quality
Inkblot
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The last few times I've listened to Radio 1 in the car I've found the audio to be slightly distorted. If I turn off RDS and manually tune to 98.8 from Wrotham it sounds a little better but if I then turn RDS back on I can hear the sound get louder as the radio retunes to 98.5.
Is the audio on the Radio 1 London transmitter deliberately slightly louder than Wrotham, or slightly more heavily compressed, and if so, why?
Is the audio on the Radio 1 London transmitter deliberately slightly louder than Wrotham, or slightly more heavily compressed, and if so, why?
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I must admit (though I can't receive 98.5 well enough to comment) that I also find the audio quality on 98.8 shockingly bad - as you say, distorted as though the levels are too high. Have not noticed this problem on Radio 2 FM which still seems to offer (to my ears) a good quality.
Technically the Crystal Palace fill in transmitter was very cleverly engineered by the BBC to allow it to be that close in frequency to the Wrotham transmitter.
You can read how they did it here.
It does sound like 98.5 is a little louder and a little distorted, but 98.8 sounds fine, so there may be the problem with the link from Wrotham.
It could be a bit of 'splashover' from 98.8 Wrotham on your receiver, there might be an imbalance and it's slightly less selective at rejecting signals at +300 kHz, than it is
at -300 kHz. Of course (see BBC R&D paper) the actual separation is 304 kHz.
Having said all that, Radio 1's audio quality is a disgrace whatever platform or transmitter you use.
The Band II frequency plan grouped the national networks into sub-bands (hence the familiar punchline '88 to 91' for Radio 2 etc) so it needed to be nearby. However, no other frequency in the London area was available so a formerly taboo slot had to be investigated.
Clever wizardry allowed this to work without causing interference, so R1, R2, R3, R4 and Classic FM now have a vertically polarised Crystal Palace filler 304kHz below Wrotham.
The only downside, is because of the very accurate transpostion required, the CP transmitters must rebroadcast the signal from Wrotham. The unfortunate side effect is if (and it has in the past) Wrotham fails, off goes R1-4 & Classic from CP too.
It would be useful if CP could switch to its own input feeds should Wrotham fail, but that's expense, getting standby feeds to CP, and arranging the for the Txs to have auto changeover equipment.
However, I'm surprised they don't. Wrotham serves 13 million homes (including London either directly or through CP), CP FM itself 8 or 9 million, quite a chunk of the UK population.
It's a good question, using Wrotham minus 400 kHz would put CP 200 kHz above Rowridge, that's the geographically nearest potential conflict, which wouldn't have been a problem.
There must have been some local oscillator relationships that prevented the use of those freqs ?
I'd forgotten about Bow B, but I don't think either Tx are strong enough in London to cause any grief, and certainly not the reverse ?
It's odd that it is louder. It's a direct transposition of Wrotham, so I would have thought
whatever deviation Wrotham is set to, would just transparently be replicated at CP too ?