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Old 23rd Jun 2005, 3:59 pm   #1
KD4BBM
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Default Age range for 405 TVs

I’m researching the UK’s conversion from the 405 line standard. I’m hoping to draw parallels to the current 525 to HDTV conversion in progress in the USA. From the excellent 405 Alive web site, I’ve learned that the last 405 transmitters went off the air in 1985. But when were the last TV sets sold? I remember from a CNN story at the time that there were still many 405 viewers who instantly lost television when these stations went dark.

In the USA today, stores still tell more 525 line Analog sets than HDTV sets. Yet our regulators, the FCC, plan to shut down the analog transmissions as soon as 2007. Making sets less than 2 years old obsolete.

So, again, can anyone give me some information about the years that 405 sets were sold as new?

Thanks!

Ray, KD4BBM
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Old 23rd Jun 2005, 4:12 pm   #2
paulsherwin
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Default Re: Age range for 405 TVs

Pretty much all TVs sold after BBC2 started in 1964 were dual standard, so by 1985 the number of 405-only TVs in use was very small. Dual standard TVs remained popular in some areas well into the 70s because of UHF reception problems, but by 1985 the national transmitter network had been supplemented by many hundreds of relays and few people relied on VHF 405 line services. The move to colour also drove UHF 625 line adoption since the 405 line system was always B&W (though experiments were made with NTSC in the late 50s).

I'm not sure how much of a parallel there is between the US switch to HDTV and the phasing out of the UK 405 line system. A better parallel is the UK switch to digital terrestrial currently underway. This is a standard definition widescreen system. So far market penetration is based on settop boxes rather than integrated TVs. The first analogue switchoff has already taken place (a tiny village in Wales) and the whole of Britain should be digital only by 2013.

HTH, Paul

Last edited by paulsherwin; 23rd Jun 2005 at 4:26 pm.
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Old 23rd Jun 2005, 4:20 pm   #3
Hybrid tellies
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Default Re: Age range for 405 TVs

Hi Ray
I am sure the last duel standard sets (405/625) to be made would have been around the 1970-1972 mark. Although all three channels were available on 625 lines from November 1969 it took many years to extend the UHF 625 line coverage across the country.
So 405 line sets would have been on sale from 1936 to the very early 1970's, obviously a gap for the second world war and most tv's built from 1962 would have been duel standard as the new BBC2 service which opened in 1964 was on the new UHF 625 line system.
Its interesting that report on CNN, over hear the 405 line closedown was very low profile and I heard afterwards that only 20-30 viewers were left blacked out, this despite months possibly years of warning.
As reguards to the coming digital switchover in 2008, most new sets in the shops are still analogue only!
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Old 23rd Jun 2005, 4:29 pm   #4
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Default Re: Age range for 405 TVs

Ray

We have similar issues in the UK with analogue switch off due in a few years. Most TVs in the shops are analogue only though they do have a Scart connector for use with a set top box.

In the UK, 625 transmissions started in 1964. After this date virtually all sets sold would have been dual standard though a few would have been so-called convertible. I say "so-called" because I suspect that very few sets were actually converted. Any 405 only sets sold after this date would have been old stock. The 405 services were duplicated on 625 starting in 1969 so after that date many sets would have been 625 only. The last dual standard sets might have been around 1973?

In 1985, when the last 405 service was switched off, the number of people actually using 405 only sets must have been minute. It would have saved a lot of money to turn off the 405 transmitters a few years earlier and buy the few affected people a new TV! OK, a few would have fiddled the system by digging out ancient sets and claimed that they were still using them.

There are some important differences between then and now. Then, sets were much less reliable. This made rental very popular, especially in the dual standard era. The other big difference is the real cost of a TV. A small TV is now a casual purchase. You can get them at the supermarket along with the soap. Even a fairly sophisticated TV is much cheaper in real terms than any set in the 1960s. Flat panel sets (LCD, plasma) are still relatively expensive.

Hope this helps
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Old 23rd Jun 2005, 4:40 pm   #5
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Default Re: Age range for 405 TVs

I believe the latest 405-only TV sold in the UK was a 12inch mains operated portable sold about 1967/8. (A British Radio Corporation (BRC) chassis which I forget the number of.) It was a low price (for that time) mains powered portable and for that reason I believe was 405 VHF only. It meant it only received BBC1 and ITV and not the new BBC2 on 625 UHF which was less popular with many viewers.
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Old 23rd Jun 2005, 6:15 pm   #6
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Default Re: Age range for 405 TVs

The 6 buttons on that set were a cruel illusion. Here are the start dates for our channels:

BBC (later BBC1): 1936. 625 from 1969
ITV: 1955. 625 from 1969
BBC2: 1964
Channel 4: 1982
Channel 5: 1990?

The early dual standard colout sets were horribly unreliable. Rental made a lot of sense. 1967 saw the world's first all transistor colour TV, the Thorn(BRC) 2000 chassis. Not stunningly reliable and too expensive to make! Its successor, the 3000 series may not have been the best single standard design but was a huge commercial success.

It's worth noting that the UK has a single nationally planned system of TV channels and transmitters with the aim of near 100% population coverage. The exception is the ITV regional variations. The US system is largely locally based with rural areas largely unserved until satellite came along.

In the US, terrestrial digital uses 8VSB which is very prone to multipath. UK uses COFDM (the inferior 2K carrier version) while the rest of Europe uses 8K COFDM. These systems work well apart from broadcasters who use too much compression and the limited coverage until the analogue TXs are turned off to liberate channels and allow increased power.

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Old 23rd Jun 2005, 7:17 pm   #7
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Default Re: Age range for 405 TVs

Quote:
Originally Posted by KD4BBM
There are still B&W sets sold here, so I’m guessing there will always be a market for bottom line products.
The only B&W TVs sold in the UK now are small 5" CRT mains/battery types which include a radio and cassette or CD, sold through larger general stores (such as Woolworths) rather then electrical retailers. My partner works for Woolworths and says they have quite a few returned because they are not colour, even though this is clearly stated on the box and display (people now expect TVs to be colour).

You can buy a 14" portable colour set from around £49 (approx US$80) now (Beko 14272TDS from Argos, ref 530/3063), and I doubt a B&W set could be made any cheaper.
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Old 24th Jun 2005, 5:26 pm   #8
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Default Re: Age range for 405 TVs

Booby is right about cellular being earlier than I thought.

I did a little more research and found that Bell Labs first proposed the cellular concept in 1947. Motorola first demonstrated the technology in 1973. I still don't think that the Pilkington decisions in 1964 could have been influenced by the possible re-use of Bands 1/3 for cellular. PMR perhaps, but not cellular. In any case band 1 does not have the right propagation characteristics for cellular. Range is too great for good cell re-use. Even band 3 might be a problem here. Hence the use of UHF and low microwave frequencies.

I have Bell System Technical Journal for the 1940s so I'll try to find the original sources.
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Old 26th Jun 2005, 4:45 am   #9
KD4BBM
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Default Re: Age range for 405 TVs

Does anyone have a reference to show what frequencies your UK bands translate to? This explains the US standard:

http://www.arrl.org/tis/info/catv-ch.html

As you can see, we have three bands. VHF low, VHF hi and UHF. Our channels 2-6 suffer from ducting and should have been the first to lose, but instead we’re losing the top of the UHF band to sell more spectrum to the highest bidder.

Also, while I’m at it… from a trip to London in my early teens, early 1970’s, I seem to remember hearing police transmissions on the FM band of my US radio. Our FM is 88-108 MHz. Is this right or was I hearing things? Seemed like an odd thing to hear police in a band so easy for the public to hear.
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Old 26th Jun 2005, 6:22 pm   #10
Dave Moll
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Default Re: Age range for 405 TVs

Quote:
Originally Posted by KD4BBM
Does anyone have a reference to show what frequencies your UK bands translate to?
The following web page may give you what you're looking for:

http://ukspec.tripod.com/spectrum.html
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