Was it possible to convert 625 lines to 405 lines at the time of 405 switch off?

[Mike. Watterson]

405 sets used as bedroom 2nd sets up till closedown, especially popular in 1970s
Only BBC2 was missing till November 1982
BBC2 was shorter hours in most of 1970s
Most bedroom time viewing by younger people would have been ITV /BBC1 in 1970s

Probably they could have turned off in 1982 / 1983 with no extra complaint.

Ireland had only been partially 405 since start of TV in 1962 (West and south west never had 405) and it was close about the same time as UK 405.

VHF Band III 625 only closed 2012
VHF Band 1 VHF closed in 1999

A VHF + UHF tuner VHS was no use for 405. Wrong video modulation polarity and sound offset and sound modulation. The modulator is UHF and Wrong video modulation polarity and sound offset and sound modulation.
I still have some CRT TVs and VHS. The only difference is 42MHz to 862 MHz tuning (approx) with usually with gap at band II & airband. Though a Philips VHS I had, had no gaps and you could hook video out to audio amp and tune anything (though with stupidly wide 6MHz bandwidth!)

[FERNSEH]

Fortunately by the mid eighties reasonably priced ADC and DAC chips became available so that low price standard converters could be constructed.
Even so, the humble CA3300 6 bit ADC was priced by RS at £30. The cheap DAC08 could do the DAC function. These vital components could be supported by TTL ICs, which as you all know are cheap as chips. And as most of you know this what I did in 1985. The prototype converter is still alive and is looked after by another forum member. which is just as well because it was about to chopped up for spares in 1990.
That little converter is almost thirty years old.

DFWB.

[Brigham]

I experimented with a VHF/UHF VCR when 'the end' was obviously near. I got no pictures, but found I could record the sound on the helical scan, which produced interesting effects when the 'still picture' mode was used.

[Peter.N.]

Originally Posted by Okto1984

Thank you each for the explanations.

The thing I'm wondering now, although it's probably not one single reason, is why did people keep their 405 line sets after the signal ended?

For us!

Peter

[kalee20]

Originally Posted by KeithsTV

Around 1984 I was working in Menai Bridge ... I could hear a distinct 10k whistle as I passed one house...

A friend of mine ... later told me someone came into the shop to say their TV was faulty as there was no picture...

So there were at least two households watching 405 line TV on Anglesey

Although, it might have been the same TV. But yes, there was at least one 405 line set in use up to the end.

[Andy Doz]

Originally Posted by Brigham

I experimented with a VHF/UHF VCR when 'the end' was obviously near. I got no pictures, but found I could record the sound on the helical scan, which produced interesting effects when the 'still picture' mode was used.

I managed that too!

[Okto1984]

Originally Posted by dsergeant

I am a bit surprised that by 1985 there was ANYONE watching 405 lines

I was very young in 1985, so it's all a bit of a mystery to me what people were up to at the time! Sounds like most people had replaced their set by then. However, the newest set in our house is about 32 years old, so older than some 405 line sets were in 1985. It's often surprising what old things people are still using.

[dave walsh]

That explains the significance of being able to record 405 on VHF I suppose John [HTC post 20] Presumably only a few people could rig up a convertor before devices like the Aurora arrived [apart from Gerry Wells perhaps with his enormous ex-Broadcaster Organisation headboard]. Still using a 405 set for receiving Broadcast TV in 1985-well that really is hanging on to your old technology isn't it?. As desargent said, most people were on UHF by the seventies. CH4 arrived in 1982 and certainly wasn't duplicated on 405

Slightly OTT but I recall at the next switch-over, uhf-digital, the reassurance in the media that any TV [scart or not] could be converted to Freeview was often complicated by the presence of a 405 line set!
Dave W

[FERNSEH]

The youngest possible TV sets which were made for 405 lines were the Bush TV191D and TV193D. Both models were still available in 1972 and possibly the year later. These sets were fitted the compact version of the A640 chassis and were made in the Bush factory in Dublin.
So it follows that sets like these could possibly be only twelve years old when 405 transmissions closed January 1985. Of course the Bush set were still usable because they were dual standard.
GEC offered their dealers a dual standard TV receiver in 1972.

Can anyone think of another manufacturer which offered a dual standard TV set?

DFWB.

[SteveCG]

... I was watching 405 line TV to the end. "Top of the Pops" never looked right in 625 ...

[Restoration73]

Although the date of the stock may be older, I am sure the Thorn 1400 was still available
(BEAB label) well into the 1970s.

[Panrock]

Originally Posted by Brigham

Was anyone on here ready to convert 625 to 405 in time for the switch-off?

Not at the switch-off itself, but I was able to shortly after. I was fortunate enough to be given the digital standards converter from Sutton Coldfield on 'long term loan'. It then did duty in my airing cupboard for about 20 years. Later, when I obtained a Domino, the old converter was passed on to the BVWS.

In the later stages of the 405-line service, the strength of the signal often was reduced. For example, I understand that at Sutton Coldfield, the reserve transmitter was brought into full-time service (giving a 10dB reduction) and toward the end even this was replaced with a S.T & C CG1 (reducing the signal by a further 10dB). So at the end the peak-white vision e.r.p from SC must have been only 1 kilowatt, not the 100 kilowatts as published by the BBC. No wonder my receiver noticed the difference! I still got a good (if noisier) picture though from the 'X' aerial on my chimney.

Steve

[FERNSEH]

Originally Posted by Brigham

Was anyone on here ready to convert 625 to 405 in time for the switch-off?

I commenced my experiments to construct a standards converter late 1984, and did achieve some results by Christmas that year.
Unfortunately on account of the high pressure of work in the shop those days and because my health deteriorated early 1985 the prototype converter was not ready until later on that year.
See post #22 in this topic.
So until the converter was ready I used 405 line VHS recordings and supplied the vision and sound through a modulator built according to the design which appeared in the Practical Television magazine.
"System A modulator for 405 lines" PT August 1984.

DFWB.

[SteveCG]

I concur with Panrock about the ERP reduction. In the dying days SC (B4) was just about usable (with an H aerial), whereas Wenvoe (B5) was no-longer. LL Wells on B1 -at some range it must be said - was usable on a horiz B1 H aerial.

[FERNSEH]

Read about the Sutton Coldfield transmitter and the installation of the ST&C CG1 here: http://tx.mb21.co.uk/features/coldfield/08.shtml

DFWB.

[Panrock]

Re: http://tx.mb21.co.uk/features/coldfield/08.shtml (above) it is likely that the ex-Sutton Coldfield CG1 that went to Birmingham Science Museum is one of the two that are now held by the BHTG, whose idea was to use them for broadcasting again. See http://405-line.tv/

Steve

[winston_1]

Originally Posted by FERNSEH

Can anyone think of another manufacturer which offered a dual standard TV set?

All the main manufacturers made dual standard sets. They were necessary between the start of BBC 2 and simulcasting of the other two channels.

There were even dual standard colour sets, PAL 625 and mono 405. Thorn 2000 chassis, Philips G6 to name a couple.

[FERNSEH]

[QUOTE=winston_1;739228]

Originally Posted by FERNSEH

Can anyone think of another manufacturer which offered a dual standard TV set?....... after 1972.

I omitted to add the year.
The first dual standard set in the UK was the Pye V700D, intro year was 1961.
The V700DU was fitted with an UHF tuner.

JohnHKS reminded me that the BRC 1400 series dual standard receiver available as late as 1974. As mentioned earlier in this topic it would have been made to conform to BEAB requirements.

DFWB.

[Mike. Watterson]

Originally Posted by FERNSEH

The first dual standard set in the UK was the Pye V700D, intro year was 1961.

Possibly for Irish Market?
Ireland started 31st Dec 1961, one channel. A mix of 405 and 625, but no UHF till 1970s. Some sites were VHF only for some channels till 2012 closedown. Last Band 1 625 was 1999 at Maghera, Co. Clare, which started early 1962 and never had UHF till TG4 started. It and other Western and South Western sites never had 405.
405 was used on Irish sites were a substantial number of people had been receiving BBC, UTV or HTV since 1950s using imported TVs.

I don't know if the Dundrum Pye factory (closed late 1960s or 1970 after Philips bought Pye) made TVs.

[FERNSEH]

In very early production Pye V700D TV receivers the intercarrier FM IFs were tuned to 5.5Mhz. Pye issued instructions and brass tuning slugs to retune to 6Mhz.
Ekco introduced their fully dual standard TV T398 in 1962 and in construction terms it resembled the V700D although there was no Pye input into the design.

DFWB.