Here is a list of FM stations available in Southborough on 24th August 2019.
Included are French stations audible due to unusual atmospheric conditions with the 400kW transmitter at Lille in NE France consistently strong.

On 30th December 2019, various Belgian radio stations were audible in Southborough for one day only (again due to unusual atmospherical conditions) so these have also now been added in italics.

CR = Low Power Community Radio station
X = Very weak signal
XXX =  Very strong signal
– = Audible only under certain conditions
* = Classical music station in Belgium

Iow = from Isle of Wight

88.1 88.5 88.7 89.1 89.4 89.5 89.7 90.0	R2 Guildford R2 Rowridge IoW France Musique, Lille R2 Wrotham Fra Mus, Boulougne Klara*, Brussels R2 Norfolk R2 Dover	X X – XXX – – – X
90.3 90.4 90.7 91.3 91.9 92.1 92.4	R3 Guildford Klara*, Flanders R3 Rowridge IoW R3 Wrotham R3 Norfolk Vacant R3 Dover	X – X XXX – – X
92.5 92.7 92.9 93.3 93.5 94.1 94.2 94.4	R4 Guildford Fre Rap, Boulogne R4 Rowridge IoW RIRE&, Boulogne R4 Wrotham R4 Norfolk TF Live (Electronic) R4 Dover	X – X – XXX – XX X
94.7 94.9 95.3 95.5 95.6 95.7 95.8	France Bleu, Lille BBC R London BBC Essex (South) Fra Bleu, Boulogne CR: Isle of Sheppey R1 Belgium, Egem Capital R Croydon	– XX XX – X – XX
96.2 96.7 97.3 97.5	KMFM Pembury BBC Kent Wrothm LBC Croydon Heart Horsham	XXX XXX XX X
97.7 98.0 98.1 98.6 98.8 99.3 99.5 99.9	R1 Guildford Fra Culture, Lille R1 Rowridge IoW R2 Belgium E Egem R1 Wrotham R1 Norfolk R1 Dover Fra Culture, Boulg	X – X – XXX – X –

100.0 100.1 100.2 100.4 100.6 100.9 101.6 101.8	Kiss Croydon R2 Belgium W Egem Dream 100 Essex KMFM Gillingham Studio Brussels  Classic Wrotham KMFM Wrotham Classic FM Dover	X – X X – XXX XXX X
102.1 102.2 102.4 102.7 103.1 103.3	Studio Brussels  Smooth Croydon Heart Heathfield Heart Reigate Heart Maidstone Fra Inter, Boulogne	– X XXX XXX XXX –
103.5 103.7 103.7 103.9 104.0 104.2 104.5 104.9	BBC Essex(North) France Inter, Lille Funky Esx Southend Europe 1, Boulogne BBC Surrey R’gte BBC R Kent Dover BBC Sussex H’fld Radio X, C Palace	XX – X – XXX X XXX XX
105.1 105.2 105.4 105.6 105.8 106.0 106.2 106.4	R Essex Southend France Info, Lille Magic Croydon KMFM Maidstone Absolute C Palace KMFM Canterbury Heart Croydon More R, Hayw’ds H	XX – XX X XX X XX X
106.5 106.6 106.7 106.8 107.0 107.3 107.6 107.7 107.9	Fra Info, Boulogne Campus, Lille  Vacant More Radio, Lewes CR: East Grinstead Vacant KMFM Ashford R Essex Chelmsford KMFM Hoo	– – – – – – X X X

The following map is a Photoshop montage I’ve done of the service areas of the BBC FM Transmitter network for SE England.  It illustrates why so much of the FM network is needed for the four FM National Radio services.

Transmitters that have overlapping reception areas need 3 or 4 MHz frequency spacing.  Most car radios retune automatically from one Radio 4 FM transmitter to the next, but all general home portable radios require manual retuning if you move or go on holiday. For the frequencies to type in or tune to click here: