Radio 4 reception - birdsong

[JohnJo]

As per title when listening to Radio 4 in the car there is a constant birdsong type chirping in the background which is very irksome.

It makes no difference whether the engine is running or not and it doesn't happen on any other station which makes me think it is a transmission issue.

Can anybody shed any light on this?

Not the end of the world I know but it's the only station I enjoy listening to these days!

[Barry]

Taken from: http://www.mds975.co.uk/Content/radio-reception.html



Adjacent channel interference

Adjacent channel interference is interference from a channel which is close in frequency to the one on which you are listening. It sounds like a twittering noise in the background and is consequently sometimes known as 'birdies'. The problem is usually only apparent on stereo but if the interfering channel is very close in frequency, i.e. only 50 or 100 kHz away, the effect may also be heard in mono.

The BBC's FM transmitter network has been designed to avoid such problems but if you are listening outside the published service area of the transmitter, or if there are rare atmospheric conditions, you could still suffer from this problem.


Overloading

Overloading happens when a FM receiver receives too strong a signal. It should only be a problem if you live close to the FM transmitting station. Overloading causes intermodulation distortion which very rough and discordant and this in turn will cause twittering 'birdies' in the background. The distortion will be present both in stereo and in mono. The cure for overloading is to fit an attenuator between the aerial and the receiver. Attenuators are available from radio and TV shops and they are easily plugged in between the aerial and the aerial socket. They come in various values, quoted in decibels (dB), and your, dealer should be able to advise you on the correct amount of attenuation you require.

[JohnJo]

Taken from: http://www.mds975.co.uk/Content/radio-reception.html



Adjacent channel interference

Adjacent channel interference is interference from a channel which is close in frequency to the one on which you are listening. It sounds like a twittering noise in the background and is consequently sometimes known as 'birdies'. The problem is usually only apparent on stereo but if the interfering channel is very close in frequency, i.e. only 50 or 100 kHz away, the effect may also be heard in mono.

The BBC's FM transmitter network has been designed to avoid such problems but if you are listening outside the published service area of the transmitter, or if there are rare atmospheric conditions, you could still suffer from this problem.


Overloading

Overloading happens when a FM receiver receives too strong a signal. It should only be a problem if you live close to the FM transmitting station. Overloading causes intermodulation distortion which very rough and discordant and this in turn will cause twittering 'birdies' in the background. The distortion will be present both in stereo and in mono. The cure for overloading is to fit an attenuator between the aerial and the receiver. Attenuators are available from radio and TV shops and they are easily plugged in between the aerial and the aerial socket. They come in various values, quoted in decibels (dB), and your, dealer should be able to advise you on the correct amount of attenuation you require.

Thanks for that Barry, news to me. Will put the radio in manual tune and check for adjacent channels as I don't think it's overloading as I'm about 25 miles from the transmitter.

[JohnJo]

Northern Sound "The spirit of Cavan and Monaghan" are close at 96.3Mhz, Radio 4 is 96.0Mhz. I noticed when I drove over the hill the norther sound signal dropped out and the R4 reception cleaned up perfectly. Northern sound is broadcasting from the northern counties of the Republic of Ireland and so coming in strongly in Northern Ireland and as such there is probably no tie up between the British and Irish stations regarding who's using what frequency.

Not all bad news though as Northern Sound is pretty good!

[high.spirits]

As per title when listening to Radio 4 in the car there is a constant birdsong type chirping in the background which is very irksome.

It makes no difference whether the engine is running or not and it doesn't happen on any other station which makes me think it is a transmission issue.

Can anybody shed any light on this?

Not the end of the world I know but it's the only station I enjoy listening to these days!

I agree with the other responses re adjacent channels and the FM band full of stations.
I came across this way back in the 1970's and bought a Technics tuner that had a button giving a super narrow IF frequency. It worked well. Not much help for your car radio though.