Xfm London signal strength
Inkblot
Posts: 26,889 Forum Member
✭✭✭
My roof aerial blew down in the recent storm so I had an installer over to sort it out. Whilst checking everything was OK we looked at the signal strengths of all the FM stations and almost all the Londonwide stations were full strength, which is 50 on my tuner.
However Xfm is only 24/50. Has it always been so weak? It does sound very poor in the car but I put that down to the audio processing rather than the signal strength. Now I'm wondering whether it's just not strong enough to cover the capital. I'm well within the published MCA.
However Xfm is only 24/50. Has it always been so weak? It does sound very poor in the car but I put that down to the audio processing rather than the signal strength. Now I'm wondering whether it's just not strong enough to cover the capital. I'm well within the published MCA.
0
Comments
Kiss and Smooth both 48/50 here - twice Xfm's strength. Capital Xtra on 96.9 is 17/50, but that's understandable.
Melody felt their coverage was particularly hampered by BBC Sussex on 104.8, which was both interfering quite a bit and limiting their power and direction to the south of service on 104.9.
Capital is considered the de-facto 'London wide' coverage, even when comparing DAB coverage. Other high powered stations such as Heart & LBC boom out, but others such as Smooth, Xtra, etc are either designed to cover smaller areas or limited to prevent interference with adjacent services. E.g. Smooth on 102.2 with Southern (Heart) on 102.4.
I don't think Radio Leicester needs much protecting, 104.9 at 8kw from Copt Oak, one of the highest points in Leicestershire means that it can be heard roughly over an 80 mile radius. One of the biggest coverage areas of any 'Local' station in the UK !!:eek:
Yes, when 104.9 was re-advertised in 1996, it was done so as a 'not quite' London wide service, because of power restrictions and potential interference owing to the Leicester and Sussex stations. It has a 17dB null towards West Sussex
http://stakeholders.ofcom.org.uk/broadcasting/guidance/tech-guidance/tech_parameters/
Absolute is 3.73kW from Crystal Palace.
Capital, Heart and Smooth are all 4kW from Croydon, so the power difference, location and the null on XFM's signal in certain directions, probably accounts for difference in signal strengths.
I have a roof aerial (just a Maplin `U' shaped horizontal folded dipole, so not a great one) and XFM is fairly solid even if weak. 24db on my Sony tuner from the nineties (acceptable stereo, RDS) whereas Capital is lousy, doesn't register any dbs (only starts measuring at 16) and stereo / RDS only comes and goes.
Magic is second best for me (signal wise) and Smooth third.
To be fair the aerial does a respectable job on stronger stations. For example Heart Essex registers 54db and BBC Nationals from Wrotham about 45, which is very listenable.
Incidentally Absolute has a far stronger signal than Xfm here - 50/50 on my tuner (whatever that means - higher than Kiss or Smooth, anyway), and the aerial installer commented that it was very strong on the device he was using to check the signal.
There's absolutely no proper technical assesement going on in this thread
Statements such as 17/50 on the tuner's bargraph, that's meaningless, how is the bar graph calibrated ? What absolute signal level does 50 relate to ? Unless you know that, you can't say 25/50 is 'half signal' !!!
2.9kW against 3.73kW is a difference in ERP of 1.1 dB.
And in what particular direction ?
Look at the Ofcom figures, there are larger differences in HRP radiation round the whole 360 degs for all transmitters
That's insignificant against the far bumpier response your aerial will have across the band, and the local effects of feeder mismatch and standing waves from local reflections.
And as for UK Free's map, it doesn't match what the Ofcom parameters say, it's just guess work (as is so often the case on that site)
That map shows BBC Witlshire from Marlborough on 104.9. Marlborough is 71 miles due west of Crystal Palace, and only 100W. Does anyone know whether it was taken into account when planning Xfm's coverage? Or is there some quirk of terrain that means Leicester would be more vulnerable despite being further away and on much higher power?
One possibility is that there is something specifically affecting FM reception from Crystal Palace in this area, such as the terrain, buildings etc. We get fantastic Freeview reception on a set-top aerial but FM is significantly worse.
http://www.ukfree.tv/radiomaps.php?frequency=101100000
Sorry, but I'm feeling seriously inclined to agree with Mark C on this one.
Well, (and I wish people would pay more attention to Ofcom's extensive data, rather than floss such as UK Free), the 17dB restriction towards the west for XFM is in the horizontal plane, verically it's only about 4dB. Taking a look at Smooth and Capital, they are also -4dB H and V towards the west. Other local factors must be coming in play for you.
Yes Radio Leicester makes rds traffic reports quite anoying around here. I'm always up to date with traffic issues in the leicester area here in shropshire, couple that with the strength of bbc cymru and it makes this part of the band a bit full..
Here are a couple more absurd examples.