Closure of 405 line service

[Focus Diode]

This is what's so sad about the 405-line closedown. At the time many of us never thought we'd see 405-line pictures again.

As it gave intermittent problems I even removed the system switch from one of my 1400s and hard wired it to 625.

Thankfully, scrap chassis were still plentiful by the time I re-fitted a system switch six years later!

[SteveCG]

One thing I learnt on the way was many of the 'issues' with the BBC analogue converters. I've been able to spot 'converted' material when its been shown on TV ever since!

There were indeed two Analogue converters at Wenvoe - one was described to me as an experimental version. I took the other...

By the way, I was told that the Llandrindod Wells Tx had its own digital converter.

[AidanLunn]

Originally Posted by SteveCG

By the way, I was told that the Llandrindod Wells Tx had its own digital converter.

That will have been the CO6/509 digital standards converter. I believe Llandrindod Wells (BBC-only) received this "upgrade" when Carmel UHF opened in 1973, to convert the 625 signal received from Carmel. Of course, such a off-air receiver meant it was ready to have a UHF transmitter and aerials installed, which it did in 1976.

I don't know about the IBA's arrangements for their transmitter at L. Wells, I doubt a small relay that size would have warranted a converter the size of the analogue CO6/501A and AFAIK, the IBA never purchased any CO6/509 digital converters, so I would assume L. Wells ITV continued to be a direct off-air relay of St. Hilary's or Preseli's HTV Wales service.

[SteveCG]

AidanLunn,

I also think the IBA only had analogue converters.

BTW the BBC did give me a price for the LL Wells converter but because they said they could re-use parts of it, the price was about 20 times greater than the Wenvoe stuff.

[G6Tanuki]

I didn't see the closedown of 405 but I do recall that some weeks after Moel-Y-Parc went off-air the GB2RS sunday-morning 144MHz news-broadcast came from there, using the old Band-III antennas!

[Nymrod121]

Somewhere in my collection of broadcast memorabilia I have a photo taken of the Holme Moss Band I transmitter being switched off for the last time.


Graham Swepson was in charge of the proceedings; he had an encyclopaedic knowledge of the site in general and was very much the resident 'guru' on all matters "405" ...


I'll try to find/scan/upload it.


Guy

[Lucien Nunes]

There was a serious standards converter issue here during the final months of 405 operation, the picture was unwatchable with heavy vertical striations.

34 years on and this is still a regular phenomenon here. The programme content may change with the times but a stuck shift register or dead fast switch card is still a stuck shift register etc. The reason many faults manifest as a vertical grille is that some of the store hardware is used cyclically along the length of a line, so the symptom repeats at regular spacing. For example, an input fast switch card that is not firing its sample & hold bridge will result in 16 narrow vertical bars of no content as every 36th storage element will not be written into.

Maybe we should have modes on the current-day standards converters that replicate characteristic faults of yesteryear? People sometimes depict old-timey scenes with 'film-scratch' effects, how about scallops and jogs for maladjusted quad tape vacuum guides, or stripes for a 625-405 converter that needs TLC.

[Dave Moll]

Originally Posted by Lucien Nunes

Maybe we should have modes on the current-day standards converters that replicate characteristic faults of yesteryear? People sometimes depict old-timey scenes with 'film-scratch' effects, how about scallops and jogs for maladjusted quad tape vacuum guides, or stripes for a 625-405 converter that needs TLC.

Nah! Don't stoop to their level.

[Panrock]

I used to tell myself that the mis-timed dropout compensation from 405-line VHS tapes was really "ignition interference". Didn't quite convince though...

Steve

[peter_scott]

Not rapid enough repeat?

Peter

[Panrock]

Yes, and black-looking lines (not white as to be expected from interference on a positively modulated signal). Nothing to match on the sound either. All very disappointing.

Steve

[Viewmaster]

Just to think that many TV owners here have never seen or heard genuine car
interference nor aeroplane flutter.

Maybe 405 line converters should have this desirable
facility built in.

Switchable, of course !

[peter_scott]

https://youtu.be/_5lk0XtJMV4

[Graham G3ZVT]

I suppose we should identify all the radios and TVs in the shop.

[Graham G3ZVT]

Originally Posted by Dave Moll

Nah! Don't stoop to their level.

I do agree Dave, but I have to say that I've seen asynchronous hum-bars done very convincingly on screens in animation and "gaming footage". All the more impressive as these things tend to be made by spotty yooths with art degrees.

[Nymrod121]

Re. my earlier post (#26), here are the pics taken on the day.

If memory serves, that particular transmitter was originally the reserve from Tacolneston - notionally rated at 5kW peak vision but in reality it was well down on that because the linearity was pretty bad by the end - I spent a couple of evening shifts trying to get it better but alas, it was beyond redemption. Graham Swepson (as seen here, resplendent in his BBC maintenance 'white coat') was very supportive regarding my efforts but even he agreed it was a lost cause

We had a complaint from someone a couple of miles or so away (down in the valley, t'other side of Yateholme Reservoir) when the service closed - !

Cheers
Guy

[AidanLunn]

^^That may well have been the last 405-line transmitter to close, assuming what I've heard about l. Wells' BBC 405 service aren't true. IIRC, Holme Moss refused to close down its 405 service until the Emley Moor service had gone, which it did around 35 minutes after E. Moor 405 closed!

[60 oldjohn]

Originally Posted by AidanLunn

That's already explained here in good detail:

http://tx.mb21.co.uk/features/coldfield/08.shtml

Thanks Aidan, that is a very interesting site.


John.

[SteveCG]

Aidan,

Just to confirm: Ll Wells 405 was definitely on the day after nominal closedown - I was watching it! Both Wenvoe and Sutton Coldfield had gone by then.

[Brigham]

Burnhope (Ch.8) stayed on an extra day for my birthday (Jan. 4th).