It had been planned that the BBC's 405-lineVHF television service would commence on the same date, but delays at Rowridge caused the official switch-on to happen six months later on 29 April 1957. Blaenplwyf was considered a main transmitter for VHF television (despite radiating only 3 kW ERP) as it was fed from a microwave link from Mynydd Pencarreg just south of Lampeter.
The site has a 152 metres (499 ft) guyed steel lattice mast standing on land that is itself 175 metres (574 ft) above sea level. The television and radio broadcasts were originally designed to cover the majority of the Cardigan Bay coastline, the antennas being designed for maximum ERP to the north and to the south-west.
Blaenplwyf became a main transmitter for UHFanaloguecolour television from 1970 onwards, and was transmitting all three original UHF channels in colour from mid 1973.
It currently carries all six UK digital television multiplexes.
Newspaper articles claimed that at launch, the television service would be 1 kW. The technical report from the BBC disagrees, pointing out that the mean ERP was 0.8 kW at launch, and was uprated to twice that value on 8 August 1958.
This report also points out that the signal had its maximum ERP lobe to the north, and that this had been 1.6 kW at launch and 3.2 kW after the power increase. Also, that the coastal towns to the south-west had been treated to the weakest ERP (0.5 kW at launch, 1.0 kW later). Amongst the effects of this were to leave the town of Cardigan with no signal.
BBC2 625-line UHF colour television services came to Blaenplwyf in 1970 (early for Wales). VHF television continued as before. The service area for UHF however was designed to cover more of inland mid Wales than the VHF service had been.
Despite the fact that the UK's UHF TV system had only been engineered for four TV channels, a fifth was added in 1997. In common with the situation across much of the UK, Blaenplwyf was forced to transmit this extra service well out-of-group and at low power compared with the main four.
The UK's initial experimental digital television service was rolled out, using low power for the transmissions and interleaved with the analogue transmissions in an attempt to make the whole set receivable with the original aerial group.
Digital Switchover started at Blaenplwyf. The BBC Two analogue service on channel 27 was closed down after 40 years of service. Multiplex 1 from channel 28+ was also closed and the new BBC multiplex A commenced on channel 27 at its intended full power and using 64-QAM mode and 8k carriers from the start.
Digital switchover was completed, seeing the shutdown of all the remaining analogue TV services from this site. The new digital multiplexes took over the frequencies of the analogue services plus a few new ones.
Blaenplwyf started transmitting VHF FM radio only a year and a half after the then-novel service was initiated in the UK. At launch, the service was from temporary transmitters using a temporary mast, but from 29 April 1957 the main transmitters came into service with antennas on the main mast. These transmitters were 60 kW each.
In 1960 the BBC published a technical report showing the measured service area of the FM radio services (plus those of Moel y Parc and Llanddona).
More services have been added since the late 1980s. The latter of these references notes that the Classic FM and Radio Ceredigion services are radiated from a point only 80 m (262 ft) up the mast, and together with the low ERPs of those two services, the coverage should be expected to be limited.
From 4 January 2011, Real Radio was added to the set. Real Radio's OFCOM application claims they intended to radiate 10 kW and 2.5 kW beams.