The second BBC VHF radio transmitter.

[Geordie McBoyne]

The Wrotham transmitter was the first BBC VHF/FM transmitter to start transmissions of the Home, Light and Third programs, that was in May 1955.
Well, it seems that Geordieland was the second VHF transmitter to get started that year.  The Pontop Pike transmitter in County Durham commenced transmissions in December 1955.  

Geordie McBoyne.

[ppppenguin]

I wonder how they managed to get the signals from London to "oop north" without mangling them. When they started stereo radio on VHF they couldn't even reliably get a decent quality feed from London to Brum. Hardly surprising that the BBC pioneered digital distribution systems. Their 13 bit PCM system was a revelation.

[Terry]

Noting the list that David posted raises a question: Just how much (or how little) of Band II did HMG allow the BBC to use in the 50s?

From the look of the Wenvoe allocations they appear to have been carefully shoehorned into the Band Plan although the Third Programme frequency is over 2MHz above the highest Home Service allocation. Was there something else they had to avoid here?

[ppppenguin]

Many of us of a certain age will have heard police transmissions towards the top end of Band II. It was of course illegal to listen to them but was anyone ever prosecuted? They were gradually cleared out to make room for the 108MHz top limit we have today. AFAIK even the earliest UK Band II sets went up to 100MHz and that included some of the police band.

[Terry]

Perhaps all of them?

In south Essex we could certainly pick up Essex, Kent and the Met plus I know that the City Police were still using frequencies (just) below 100MHz in the early/mid 70s although on AM.

[Old Sparky]

Here in Oxfordshire 'back in the day', it was possible to pick up Kidlington (Oxford) Airport's |Control Tower on around 100mHz

[Murphyv310]

Here you could hear the fire brigade at just below 80KHz, most sets pulled the frequency with just a little twiddle.
Back on track, as far as I'm aware the main stations are still on the same frequencies as were allocated in the fifties for the three stations, now R2 R3 & BBC regional.

[Synchrodyne]

Noting the list that David posted raises a question: Just how much (or how little) of Band II did HMG allow the BBC to use in the 50s?

The ITU 1947 Atlantic City meeting set the European Band II boundaries as 87.5 to 100 MHz.  But the UK was given dispensation to use 95 to 100 MHz for fixed and land mobile stations.

   

This was reaffirmed at the ITU 1952 European VHF planning meeting.

   

So, the apparent starting position for UK FM broadcasting was 87.5 to 95 MHz.  Presumably the upper limit moved upwards towards 100 MHz – fairly slowly, I think - as existing fixed and land mobile users were cleared from the 95 to 100 MHz band, either generally or selectively by area.  Perhaps in the Wenvoe case, the band was already free to above 96 MHz.  It was a special case anyway, in that it carried four programmes, and deviated from the 2.2. MHz programme spacing that applied in most other cases.

Cheers,

Steve

[Synchrodyne]

I wonder how they managed to get the signals from London to "oop north" without mangling them. When they started stereo radio on VHF they couldn't even reliably get a decent quality feed from London to Brum. Hardly surprising that the BBC pioneered digital distribution systems. Their 13 bit PCM system was a revelation.

As far as I know, the BBC used the established GPO landline system for early FM programme distribution, the same as used for its AM network and TV sound.  Presumably a link from Newcastle to Pontop Pike was added when that transmitter was built.

   

There was some criticism of the BBC for not upgrading its landline links for FM.  For example, in Germany the programme links were upgraded from 10 to 15 kHz in conjunction with the establishment of its FM network.

Even in 1964, there were still some shortfalls, including in respect of Pontop Pike:

       

The BBC’s comment that 10 kHz was the internationally accepted bandwidth for music circuits was a bit disingenuous when applied to FM in the 1960s.

It was true, though, in pre-FM days, and was the CCIR standard:

   

Back then the BBC was working to 8 kHz as its trunk line target:

   

And so that was the situation when FM arrived.

10 kHz, or preferably 15 kHz landlines were probably acceptable for the distribution of mono programmes, but getting a frequency- and phase-matched pair for stereo over any distance was no doubt a challenge.

Cheers,

Steve

[Hartley118]

Those audio links to the FM transmitters varied considerably in quality. My first experience of FM quality was in the 1960s from Holme Moss, and subjectively it was first class. I still have 7.5 ips tapes of broadcast concerts bearing testimony to the bandwidth.

However, when we moved to Cambridge in the mid- 1970s, quality from the 'local' Tacolneston transmitter was, by comparison with Holme Moss, abysmal, subjectively sounding like 8kHz bandwidth with associated phase distortion. I assume that was a PO 'music circuit' feed.

The only answer for hi fi at that time in Cambridge was a multi-element aerial aimed at Wrotham - not only 15kHz bandwidth, but also stereo! However, the distinctly fringe reception created a signal/noise problem. It was some years later that East Anglia got a decent stereo FM service, I guess with the advent of the BBC PCM distribution which, I understand, exploited the disused 405 line TV video coax cable links.

Was there ever use of microwave links for 15kHz bandwidth audio to FM transmitters?

Martin