Paul Homer: None of the BBC Three Counties Radio FM broadcasts are good along that stretch of the M25.
If you manage to receive it all the way along the M40 to the junction with the M25, then I guess you must be tuned to High Wycombe on 98.0. You may be able to pick it up on 92.1 from Hemel Hempstead (Pimlico) from around junction 18 in the Micklefield Green area, or perhaps sooner. The six or so miles in-between these two points is where reception is most difficult.
RDS Alternative Frequency (AF) can be useful in keeping tuned to a station having moved from an area where it is on one frequency to where it is on another. However, it only works where the alternative signal to be switched to is strong enough for the radio to be able to decode the RDS. In this instance, you are looking to receive the station outside the area where the signal is strong enough to offer RDS on any of its frequencies.
Thus, when driving clockwise from the M40 towards the junction with the M1, for example, the radio will not switch to 92.1 until the signal gets strong enough for it to decode the RDS data, which will probably be after the point at which the signal can first be received. Thus, you may have to manually tune between the frequencies, perhaps having stored each under a different preset. Depending on how the radio works with respect to AF will depend on how easy this is -- different radios work differently.
With some radios, AF cannot be turned off, and this can be a nuisance. In other cases it can be set as on or off per preset, or on or off for all presets together (in the settings menu). If it's possible to turn it on/off per preset then this is the easiest to work with: store the frequencies under different presets with AF off. Then change as you move, working out where each is best.
Coverage maps by transmitter/frequency for FM stations are here:
The coloured area shows where the signal level is projected to be at or above a predefined level. This isn't to say the broadcast can't be received outside that area. But as you can see, the coloured area for 92.1 begins around Micklefield Green. The question is, how far before that point can it be picked up well enough to listen to, without too much hiss and intermittent fading?
Judging by coverage maps I guess that 103.8 might be the one to try first along that length of the M25. Much of the motorway there runs north/south and the transmitter is roughly due north, so in line with the road which runs in a cutting along some of its length.
Friday 10 May 2024 11:56PM
Paul Homer: None of the BBC Three Counties Radio FM broadcasts are good along that stretch of the M25.
If you manage to receive it all the way along the M40 to the junction with the M25, then I guess you must be tuned to High Wycombe on 98.0. You may be able to pick it up on 92.1 from Hemel Hempstead (Pimlico) from around junction 18 in the Micklefield Green area, or perhaps sooner. The six or so miles in-between these two points is where reception is most difficult.
RDS Alternative Frequency (AF) can be useful in keeping tuned to a station having moved from an area where it is on one frequency to where it is on another. However, it only works where the alternative signal to be switched to is strong enough for the radio to be able to decode the RDS. In this instance, you are looking to receive the station outside the area where the signal is strong enough to offer RDS on any of its frequencies.
Thus, when driving clockwise from the M40 towards the junction with the M1, for example, the radio will not switch to 92.1 until the signal gets strong enough for it to decode the RDS data, which will probably be after the point at which the signal can first be received. Thus, you may have to manually tune between the frequencies, perhaps having stored each under a different preset. Depending on how the radio works with respect to AF will depend on how easy this is -- different radios work differently.
With some radios, AF cannot be turned off, and this can be a nuisance. In other cases it can be set as on or off per preset, or on or off for all presets together (in the settings menu). If it's possible to turn it on/off per preset then this is the easiest to work with: store the frequencies under different presets with AF off. Then change as you move, working out where each is best.
Coverage maps by transmitter/frequency for FM stations are here:
http://a-bc.co.uk/mca-measured-coverage-area-maps/
The coloured area shows where the signal level is projected to be at or above a predefined level. This isn't to say the broadcast can't be received outside that area. But as you can see, the coloured area for 92.1 begins around Micklefield Green. The question is, how far before that point can it be picked up well enough to listen to, without too much hiss and intermittent fading?
Judging by coverage maps I guess that 103.8 might be the one to try first along that length of the M25. Much of the motorway there runs north/south and the transmitter is roughly due north, so in line with the road which runs in a cutting along some of its length.