FM Radio problem - any experts?

murfitUK · 25-06-2007, 18:03

My stereo in the living room is permanently tuned to BBC Radio 4 on 92.7 FM. It has an external aerial mounted on the chimney next to the TV aerial.

Today, 92.7 is silent. There is no noise, crackling, hissing etc - nothing at all, absolutely blank. I pressed a few buttons and got radio 1, radio 2, radio 3, and the local BBC Radio Stoke as well as the local independent channels like Signal. Managed to get radio 4 on 93.3 but its a bit hissy. Everything seems OK except no radio 4 on 92.7.

However... my bedside radio works fine for radio 4 on 92.7. The aerial is only a bit wire hanging out the back.

What's the problem?

Could the external aerial be picking up a different transmitter than the bedside radio? But then, they wouldn't be transmitting on the same frequency, would they?

I'm in Stoke and I think our radio comes from the Sutton Coldfield transmitter. I've looked on the BBC reception webpages but there is no indication of any problem.

???

andygrif · 26-06-2007, 00:13

All sounds a bit strange....I guess it's technically possible that the bedside radio could be receiving the transmisson from a different transmitter on the same frequency in another location, as your external one is probably more directional than the bedside one.

However I would think this explanation to be extremely unlikely as there is little crossover of broadcasting freqencies that close together geographically to avoid strange problems and also the one in the living room would also be likely to pick up at least some of the 'other' tranmission.

You've already tested the other channels on the living room radio so it's not likely to be the nearest BBC transmitter, the fact that you can pick it up on the bedside one confirms this. I also assume that you've checked all the connections on the living room radio, aerial connections etc.

The only possible thing I can think of testing is to check to see if changing the mono/stereo button (if you have one) might do something. Some stereo tuners, when you select mono, just take one channel of the broadcast rather than a mix of the L+R channels...so as it's Radio Four there's a distinict possibility they're broadcasting a play or similar in one channel only. The one you have by the bedside is more likely to be a mono radio, so could work fine.

If it's not that, then I guess we could be looking at a very odd fault with the stereo tuner. If it's digital, you could try doing a sort of reset...unplug it from the mains for a few days until it loses all its settings and then start again.

Perhaps someone else might have a more specific idea...hope this helps a little.

murfitUK · 26-06-2007, 00:32

The downstairs stereo is a Denon and it was working OK this morning when I was listening to the Today programme. I switched it back on just before 12 in time for You And Yours - but nothing.

My bedside one is a Bose. I took it downstairs and plugged the external aerial in. Again - R4 on 92.7 is completely silent, but OK with the "little bit of wire" aerial upstairs.

Downstairs, all the presets for the other BBC stations work fine. Just not R4!

Uncle Peter · 26-06-2007, 01:03

It sounds like water has found it's way into the feed point on your external aerial and over time the centre core of the coax cable has corroded and parted company with the receiving element.

The net effect is that you're probably using just the length of coax as an antenna. When a signal drops into the static does your receiver mute itself? this could explain why you're hearing nothing at all.

jingleman · 29-06-2007, 17:00

Take a look at this discussion:
http://groups.google.com/group/uk.tech.broadcast/browse_thread/thread/f8dd4f57da37c475/5880a68fe96dd22c#5880a68fe96dd22c

There are BBC techies that read this group. That said, I think the BBC TX sites are now oustourced, as ITVs, and are run by what was NTL (you can't escape them), now called Aquiva.

andygrif · 30-06-2007, 09:56

Sorry to go off topic, but the key word there is 'used' to be...the actual chain of events was the NTL was bourne out of the IBA's Engineering arm, back in the days when we only had the IBA and the BBC.

The BBC had their transmitters, the IBA (ITV and commercial radio) had theirs. When it was all privatised, the IBA became NTL a hugely successful and innovate company (and nothing to do with the cable company at this stage).

NTL had just finished laying fibre cables all around the UK and CableTel bought them out, which was a smart way of getting a very expensive network as part of the deal.

They had to sell it off, as it was one of the most valuable assests of the new company and ntl had no money, hence Aquiva - nothing to do with the cable company anymore, still a respected (although not as innovative as it used to be, as they asset stripped it) transmission company.