A 300 metre exclusion zone is now in place around the Bilsdale transmitter in North Yorkshire.
The mast near Helmsley which provides TV signal for North Yorkshire and the North East has caught fire on Tuesday.
The transmitter sends a signal to approximately 570,000 houses across the region – only viewers who receive their television via Freeview are affected.
Radio services affected include BBC Radios 1-4, Radio Tees & BBC DAB, SDL, North Yorkshire DAB, BAUER Teeside, Digital 1, TFM, Capital, Heart & Classic FM.
Arqiva, which owns the transmitter, has apologised for the inconvenience.
Emergency services confirmed that crews had been sent to the site at around 2pm today (10 August) after smoke was seen issuing from it.
The 314-metre structure was built in 1969 to bring colour television to Teesside for the first time.
The coverage area encompasses Harrogate, York, Filey, Whitby, Middlesbrough, Stockton, Darlington, Bishop Auckland, Hartlepool and Barnard Castle.