Were there any all valve FM stereo radios?

[John_BS]

Originally Posted by John_BS

NICAM = Near Instantaneous Companding & Multiplexing". The Companding is from the sampled 14 bit input to a "sliding" 10-bit output. So in any 1mS time-slot slot, the signal is represented by 10 bit words, accompanied by a (patented) signalling of the amplitude "range" within which the 10 bits lay. So I'm afraid we're talking 14 bit resolution.... and 10bits at any one mS of time..... works well, doesn't it?

I'm pretty certain that the 13 channel distribution was nowhere near 16 bit (it was really hard to make high-performance a to d's from discrete components in 1970!) but I'll check with One Who Knows Definitively and get back!

John

The first audio digital distribution system adopted by the BBC was (mono) sound-in syncs for carrying the TV sound and hence avoiding additional BT sound line rental. This was 10 bit linear, but there was an analogue compandor (+limiter) used to improve s/n. See http://en.wikipedia.org/wiki/Sound-in-Syncs for dates etc.

The 13-channel system was developed as a follow-on project, and the BBC developed a dual-slope a-d with 13 bit resolution. They also used some dither to mask any coherent quantising noise. So the system was, by chance, both 13 channel and 13 bit. The signal was distributed in binary baseband format over standard analogue TV circuits.

John

[soundhog]

Originally Posted by Michael Maurice

At first Capital did switch off the pilot tones on some programmes, Do you remember Roger Scott did a programme call Three O'Clock Thrill? I still have a couple of these recordings where he revisits the late 1950's, at the end of the show theres a little beep as the station switches back to stereo.

I've got recordings of some late '70s Kenny Everett Capital shows, containing a few instances where they switch from stereo to mono to play a record in rough condition, then back to stereo afterwards. Ken obviously made a big thing of it: 'Watch the little green light on your radio... hnnngh!'

[Synchrodyne]

Originally Posted by Sideband

......and if anyone want's to see a monster stereo Nordmende radio that I repaired back in 2009, it's here: https://www.vintage-radio.net/forum/...ad.php?t=43204

Thanks for that - a most interesting thread. So valve stereo decoders were used by European manufacturers as well as American, but evidently not by any in the UK. By the way, I hand't heard of the EMM803 tuning indicator before - an unusual but logical device.

Cheers,

[neon indicator]

Stereo was later in UK than in USA and Germany and took over 15 years to roll out (from mid 1960s to late 1970s for the majority), Some people didn't get Stereo until nearly 20 years after original tests.

[Synchrodyne]

When did Germany start stereo FM broadcasting?

The USA started in 1961, still in the valve era, the UK in 1966, by which time solid state was taking over. But UK stereo decoder production for export models started around 1964, I think? That would have been on the cusp - perhaps a toss-up between valves and germanium transistors.

Cheers,

[Paul Stenning]

There is some discussion about the BBC FM transmission path (link from studio to transmitter) here https://www.vintage-radio.net/forum/...ighlight=nicam

In post 16 Mark Hennessy confirms that NICAM is used and is unlikely to change until the eventual switchover.