When did BBC Radio 1 go stereo? and FM?

[krabapple]

Don't know where to put this except this general forum.

For research reasons I'm trying to pin down when BBC Radio 1, a longstanding UK radio station went from mono to stereo broadcasts . (I presume I mean FM radio rather than AM, but I'm unfamiliar with UK broadcast history.)

I'd also like to know the audio bandwidths, of AM or FM, mono or stereo, in the UK, circa the late 1970s.

Also: when the switch happened, was it for all broadcasts, or just certain 'special' shows, on Radio 1?

 

[staticV3]

Here's a neat website that outlines BBC's switch to Stereo: https://www.radiorewind.co.uk/radio1/transmitter.htm

 

[dougi]

Broadcast AM audio bandwidth is 9-10kHz, depending on channel spacing raster (I think UK has always been 9kHz, but unsure). Australia changed from 10kHz to 9kHz in late 70s.

FM audio bandwidth is typically 15 kHz, for 200kHz channel spacing with typical maximum FM deviation of 75kHz. I don't think the UK has significantly changed their technical parameters since the 70s.

 

[Berwhale]

You should not refer to 'BBC Radio 1' as 'BBC1' - BBC1 is a TV channel.

 

[krabapple]

Here's a neat website that outlines BBC's switch to Stereo: https://www.radiorewind.co.uk/radio1/transmitter.htm

yeah, I've seen that, though it's a bit confusing as much of it seems to concern the Washford transmitter. I dig the geocities-era page look, though.

Wikipedia 's 'FM stereo entry relies heavily on that site for its UK info, but this bit interests me in particular:

When the BBC's radio networks were renamed Radio 2, Radio 3 and Radio 4 respectively in 1967 to coincide with the launch of Radio 1, the new station was the only one of the main four to not have an FM frequency allocated, which was the case for 21 years. Instead, Radio 1 shared airtime with Radio 2 FM, on Saturday afternoons, Sunday evenings, weekday evenings (10 pm to midnight) and Bank Holidays, eventually having its own FM frequency starting in London in October 1987 on 104.8 MHz from Crystal Palace.

what exactly does 'shared airtime with' mean?

 

[krabapple]

You should not refer to 'BBC Radio 1' as 'BBC1' - BBC1 is a TV channel.

Ah, right, fixed that.

 

[RPoitou]

Lots of detail here - http://www.frequencyfinder.org.uk/Radio1_Transmission_History.pdf

 

[krabapple]

Thanks for that! Very informative . It clears up the 'shared airtime' thing I think:

BBC RADIO 2/ RADIO 1 VHF
As Radio 1 Mon-Fri 1400-1630 and 2200-0000, Sat 0800-1000 and 1300-1930, Sun 0830-1000 and 1800-1900
As Radio 2 at other times, opting out with music when LW carries sport
FM: 88.1 - 90.1, 91.1 MHz, see table

which I take to mean, Radio 2 broadcast Radio 1 content (in FM) during the days and GMT hours indicated. And that was in stereo in most locations, as indicated by the table shown below that on that page (mono was only in a few locales)

That pretty much answers my research question.

 

[krabapple]

FM audio bandwidth is typically 15 kHz, for 200kHz channel spacing with typical maximum FM deviation of 75kHz. I don't think the UK has significantly changed their technical parameters since the 70s.

OK, I'll take 15 kHz as the UK FM stereo bandwidth of BBC Radio 2 circa the late 1970s, unless someone tells me otherwise.

I guess the remaining question is....at those times when BBC Radio 2 broadcast Radio 1 content, does that mean the content was simultaneously available on Radio 1 in AM mono (with less bandwidth)? It would seem obviously 'yes', but just making sure.