Fone Forum

If you are moving to a new area and want to check which network gives best coverage there, it is possible to travel to the area, do a manual search for networks on your mobile, and compare the relative strengths of the signals detected.

However, not everyone will have the time or opportunity to do so.

All of the UK networks provide some sort of coverage map on their website, however approximate.
They should be a reasonable indication however.

The URL's needed to do this are:-

O2: http://www.webmap.o2.co.uk/?Search=Search (http://www.webmap.o2.co.uk/?Search=Search)

Orange: http://coverage.orange.co.uk/uk/UKCoverageSearch.htm (http://coverage.orange.co.uk/uk/UKCoverageSearch.htm)

Three: http://www.three.co.uk/personal/coverage_/coverageChecker.do (http://www.three.co.uk/personal/coverage_/coverageChecker.do)
(though their 2G coverage is obviously the same as Orange as they use them for 2G coverage)

T-Mobile: http://www.t-mobile.co.uk/services/coverage/street-check/ (http://www.t-mobile.co.uk/services/coverage/street-check/)

Vodafone: http://maps.vodafone.co.uk/coverageviewer/web/default.aspx (http://maps.vodafone.co.uk/coverageviewer/web/default.aspx)

Whilst this is true, note that the home network of the SIM card is always set at the top of the list if in range, and only the rest are independently ordered by signal strength

Therefore a more realistic result comes either from using a foreign SIM with no preferred network affiliation, or using two or more UK SIMs and doing a bit of figuring in your head.

Note that sometimes a network has a stronger 3g signal than 2g, like T-mobile does where I live, and that sometimes the results are inconsistent anyway, due to signal strength fluctuating, and the transmitter power gets wound down in non-busy periods, though usually seems to pick up for this search.

My OP was just an introduction to the website coverage maps.  In fact, there could be all sorts of qualifications made.  The maps show coverage in an area, but nothing detailed like where hills or buildings may block off the signal from the nearest mast.  They definitely are of limited use.

I would suppose that the absolute ideal would be to go to the site and check signal strength on all 5 networks, but not everyone has that number of 'phones and SIM's, nor necessarily the time and opportunity of doing such research.  That is why a coverage map is still better than nothing, which is in turn the reason why the networks bother publishing them, people bother to look at them, and I posted the URL's.

I was careful not to suggest that they were a perfect or ideal method, but they may be the only one available practically in some situations.