I know there are at least a couple of you here involved with TV, telephones, etc., so I thought a brief overview of the TV system in the U.K. might be of interest, as we don't use the U.S. standard.

The original monochrome-only standard was 405 lines at a field frequency of 50 Hz. (as opposed to U.S. 525/60). Broadcast was on 13 VHF channels. Video modulation was positive with an AM sound carrier.

In the 1960s a new system at 625 lines on UHF channels opened, with negative video mod. and FM sound (as in N. America). Color was introduced in 1967 using the German-devloped PAL (Phase Alternation by Line) system.

The old 405/VHF network broadcast programs (B&W only) in parallel with the new 625/UHF until its closure in 1985, so everything is now solely UHF.

Cable is really only just catching on in the U.K., and so far is available in just a few of the large towns. Direct broadcast satellite was pushed heavily in the late 1980s, so many homes now sport an 18-inch satellite dish.

F-connectors are common on cable & satellite, but the standard for terrestrial antennas is the Belling & Lee coaxial plug, developed many, many years ago (and so far as I'm aware, practically unknown in the U.S.A.).

Both terrestrial & satellite are going to digital in a big way now, with the govt. pushing for a closedown of existing analog services within the next few years.

Paul,

You most likely know this already, but I'll post it anyway, just to add to your message.

Our Air Broadcast VHF - UHF stuff for Television and Commercial FM radio goes as follows:

VHF Lo Band [54 to 108 MHz]:

54-60 MHz = TV Channel 2,
60-66 MHz = TV Channel 3,
66-72 MHz = TV Channel 4,
72-76 MHz = Special Services [VHF service, possibly Police, Fire, Railroads, Etc.],
76-82 MHz = TV Channel 5,
82-88 MHz = TV Channel 6,
88-108 MHz = Commercial FM Radio Broadcasts.

VHF High Band [174 to 216 MHz]:
174-180 MHz = TV Channel 7,
180-186 MHz = TV Channel 8,
186-192 MHz = TV Channel 9,
192-198 MHz = TV Channel 10,
198-204 MHZ = TV Channel 11,
204-210 MHz = TV Channel 12,
210-216 MHz = TV Channel 13.

UHF band range is 470 MHz for beginning of TV Channel 14, to 890 MHz for end of TV Channel 83. Each UHF Channel occupies a typical 6 MHz bandwith.

For a typical TV Channel listed above, the AM Video Signal's carrier frequency is 1.25 MHz from just past the "Channel's Edge". It covers about 4.0 MHz of bandwidth. The FM Audio Signal's carrier frequency is about 0.25 MHz from the other "Channel Edge". The FM Carrier is 4.5 MHz from the AM Carrier. FM covers aproximately 200 KHZ [0.20 MHZ] in total sidebands, so the entire Audio Envelope has a good 200K of sound area.
The real bandwidth hog is the AM Video signal envelope!

In the receiver, for Monochrome [Black and White], the composite video signal at the RF amp [RF signal and Oscillator signal heterodyned] = 45.75 MHz.
Scanning at the CRT =
525 lines horizontal [212.5 for odd, 212.5 for even - common interlace] Horizontal frequency = 15,750 Hz [525 lines x 30 Hz].
Vertical oscillator frequency = 60 Hz.

Vertical = Sawtooth waves, Horizontal = Square waves or pulses.

In a Color set, the Horizontal Frequency is less than 15,750 Hz. It's been a long time since I covered TV stuff - especially Composite RGB [Color], so I'll need to grab the books and do some refreshing!!!

The Commercial FM Radio Channels Data is something like:
IF Frequency = 10.7 MHz [both Mono and FM Stereo],
Bandwidth = 30 Khz [Mono], 150 Khz [Stereo]
Spectrum = 88-108 MHz [VHF low band].

And just for the heck of it, Commercial AM Radio is:
Spectrum = 540 Khz to 1600 Khz,
IF Frequency = 262 Khz or 455 Khz,
Bandwidth = 10 Khz.
My dislikes of AM broadcasts are the extremely limited bandwidth [10 K for sound is too dang midrange for me!], and the way receivers love to pick up Atmospheric, Natural and Man-Made noise big time and deliver those signals to the RF Amp as info!

Not sure of DBS, CATV type Commercial Cable TV Broadcasts, or the newer "XM" DBS Audio, so I'll do some searching here and there.
Got any leads???

I memorized the VHF - UHF Spectrums from countless custom Parasitic Yagi Antennas projects, plus bandpass filters to block neighboring HAM Radios from stepping so hard on our signals, they would get cross modulated horribly - sometimes the video signal got pushed away completely!
Most of the time, the interference was just simple Herringbone on TV 2, 4 and 5.
But when the guy next door fired up the 10 KW 30 MHz Radio set, that's when watching any TV Channel was futile!

This was kind of fun! [what a life I lead when this is fun stuff, huh ]. Glad you posted this topic!

Scott SET

Oh, forgot to add POTS [Plain Old Telephone Systems / Service] stuff:

On-Hook voltage = 30-55 VDC,
off-hook voltage = 1-5 VDC
Ringer voltage = 90-130 VAC [something like 20 - 30 Hz],
Loop currents = 10 ma to 25 ma.
Bandwidth = 3Khz [330 Hz to 3.3 Khz].

Touch Tone signals = DTMF [Dual Tone Multi Frequency].
Full Duplex at user end[s] of loops [at sets], 2 to 4 wire at C.O. [Central Offices] or within local hubs.
The 2 to 4 wire conversion is responsible for the transmitted sound "Reflected" back to the speaker - such as when a person speaks into the microphone [of the typical landline handset], the sound can also be heard in the handset's speaker.

Can't recall the DTMF base frequencies, so I'll find that info and post later.

Scott SET

Yep, I've got most of the data on this in my reference books.

The U.K. 405-line system used 10,125 Hz line scan, which on older sets was often quite audible. The original VHF carriers when BBC-TV started were 45 MHz video, 41.5 MHz sound, later to become known as channel 1. Ch. 1 thru 5 were low VHF, called Band I here, ch. 6 thru 13 high VHF or Band III. I haven't got the exact allocations to hand at the moment, but they were in roughly the same area of the spectrum as U.S. channels.

The 625-line transmissions still in use today are UHF band IV and band V. Channels are numbered 21 thru 69, running approx. 470 to 860 MHz. Audio carrier is 6MHz above vision, and we also have a 1.25MHz vestigial sideband. Line scan is 15,625 Hz and PAL color sub-carrier at 4.43 MHz approx.

For a large part of the 1960s and into the early 1970s, manufacturers made dual-standard sets. These had a monster changeover switch which not only swapped from the VHF to UHF tuners, but also adjusted the scan frequency, switched in the appropriate filters, routed sound IF to AM or FM demod., changed video demod. polarity, etc.

I have quite a collection of 1950s/1960s journals, and the were a lot of experiments carried out to decide on the best color (UK "colour") system. The BBC did some trials with the American NTSC system adapted to 405-lines, but by the early 1960s the decision to adopt 625-lines was made, so I guess it was inevitable that PAL would be used. The phase-locked color means that our sets don't need a "hue" control.

*
VHF/FM radio started here in 1955, initially using just the 88 to 100 MHz range. When stereo was introduced, we adopted the same Zenith 19kHz pilot-tone system as in America. FM IF is standardized at 10.7 MHz, but our pre/de-emphasis is different - 50uS vs. 75uS. FM was only extended to 108MHz a few years ago; the 100 to 108 section was previously used for police radio, much to the joy of those with imported Japanese sets which would tune above 100MHz! FM radio is Band II, by the way.

AM broadcast is pretty much the same, except we have 9kHz spacing and thus an audio bandwidth of a glorious 4.5kHz! There was an eventual push to standardize the IF at 470 kHz, but older sets often used 455, 460, 465, etc.

Britain (and Europe) also use an AM broadcast band called "long wave" running approx. 150 to 300 kHz. Standard AM 540 to 1600 kHz is often called "medium wave.
Up until the 1970s, most radios made for domestic use actually calibrated the AM scale(s) by wavelength instead of frequency, so standard MW ran approx. 550 to 190 meters (UK "metres") on the dial.

(Hence the slogan of our most famous "pirate" station: "On one-nine-nine, it's Radio Caroline.")

We have digital radio in operation now, using some of the vacated old Band III TV spectrum. I'm not sure of the details, because I'm not that interested in it myself; I'm more of an "old-time" radio enthusiast.

*
One thing you all might find odd: TV sets here are required to have a license. At the moment, it costs just over £100 per year (about $150). Radios had a license at one time, but this was abolished in 1971.

Go here for some interesting TV stuff: http://www.meldrum.co.uk/mhp/


P.S. Scott: The scan freq. you're looking for is 15,734 Hz for 525/NTSC color, directly related to the sub-carrier freq. of 3.57-something MHz.


[This message has been edited by pauluk (edited 11-09-2001).]

Telephones:

All the basic characteristics are similar, although the specified sound levels vary by a few dBm.

I don't have a list of the DTMF tones handy either, but we use the same frequencies (DTMF dialing didn't arrive here until the 1980s).

Modern house station wire follows the white-blue, blue-white, white-orange orange-white etc. pattern, but older wire was just plain blue, orange, green, brown.

The cords on the phones are diferent again: red, blue, green, white. Tip is white (green in U.S.), ring is red. Green and blue are/were in various ways before and after the introducton of modular jacks in about 1982 (different to U.S. types).

Standard tones are a little different here, e.g. busy tone is just a single 400Hz tone instead of a double frequency, and with slightly different on/off timing. There's also the famous British double-ring cadence as well, well known to any Brtish movie buffs no doubt. (The ring timing is actually 0.4 sec on, 0.2 off, 0.4 on, 2.0 secs. off).

Lots of other minor differences as you might expect, e.g. the long-distance prefix is 0 instead of 1, and our emergency number is 999 instead of 911.

Scott35,
The International band of Emergency Services
has been at 154MHz, for some years, just below the Marine VHF frequencies
However, with the advent of Digital Comms, this is now all UHF Trunk-line stuff,
What I do know is the Fire Service over here in NZ, uses CTCSS and Cellphones to provide thier communications, were as we used to use Handhelds and Base sets before.
Go figure.

Paul,
When is the proposed Closedown of the Analouge systems, supposed to take place, over in the UK?.
How will people that still only have a Analouge Terrestrial system, get on?
Over here, apparently, we are supposed to be moving to a Digital Terrestrial Platform, with a proposed shutdown of the Analouge systems in 2008.
Don't think so though, they(The Gov't) can't even make thier minds up, as to what format, is going to be implemented yet, and we all know how fast governments act!.
Typical, and I bet that they will choose the one that will be obselete the soonest, too.
They'll try and do it on the cheap.
Knowing our luck, it'll probably use NTSC.

[This message has been edited by Trumpy (edited 04-13-2003).]

The last I heard, the shut-down of analog is scheduled for around 2008. There were rumors a year or two ago that the government was pressing for shut-down in 2005, but I've heard nothing more about that.

The govt. here doesn't really give a d*** about the TV service. All they're interested in is the huge amount of money they'll make by auctioning off the cleared parts of the spectrum for yet more mobile phone and other similar services.

The way they seem to be planning it at the moment, we'll be left with digital TV across a very fragmented band with other services slotted haphazardly in between.

NTSC is not a digital format. However, the digital format used for terrestrial digital
TV in North Amreica, is called ATSC.

classicsat,
Thanks for that reminder, I was just showing that I have about as much of an idea about TV systems, as what our govt over here does!.
Paul, Over here, there was to be an auction of the 2 and 3GHz bands and quite a few other frequencies, but it was prevented(thankfully!) by the Treaty of Waitangi settlement courts, but there is no way in hxxl, I am going to go there, at all!
With that in mind, our frequency spectrum over here, would have been an empty cupboard, years ago and nothing to show for it.
I just hope they don't ever start selling the Amateur and HF CB Bands, these have been the source of many hours entertainment for me, from the age of 18 onwards!

Ireland's national broadcaster RTE didn't go air until new years day 1961.

The technical history of Irish TV is interesting though. A version of the European 625 line system, later to become PAL, was used from day one.

625 lines with a 6 mhz seperation between sound and vision broadcast on VHF

BBC adopted the same system for BBC 2 on UHF in 1964.

As a many Irish viewers in areas that could pick up UK broadcasts had invested heavily in 405 line televisions RTE decided that it would mirror its 625 line system in areas that could recieve BBC with a 405 line VHF service to cater for these viewers.

Dublin cable systems carried both versions as well as BBC on both 405 & 625 lines (both on VHF) after 1964ish.

RTE began broadcasting in PAL I (RTE Colour) from 1969 onwards on a phased basis. Films and some commercials were broadcast in colour first, followed by some studio produced programming. It wasn't fully colour until the mid 1970s.

UHF began to be phased in with the introduction of RTE 2 (now Network 2) but only where it was absolutely necessary as they didn't want to have a situation where people needed extra antennas.

In the early - mid 1990s TV3 and TG4 came on air on UHF only and RTE/Network 2 began to move more transmitters over to UHF. I think the general idea is to free up bandwidth on the old VHF frequencies for various digital services.

VHF is still very much alive, well and in use in many mountainous areas of the country where UHF tends to have difficulty reaching everyone.

djk,
Yeah, I know what you mean about VHF signals, with NZ being quite hilly, in some areas you can only get VHF signals and sometimes you need up to 3-4 single channel aerials to get the full set of channels.
A good case for Satellite TV, some places over here(like the West Coast of the South Island) are only just getting TV, with the launch of Digital Satellite signals, they haven't missed much, though!

TV reception's pretty easy here unless you're in some remote deep valley. RTE normally installed really small relays to deal with valleys and villages that missed the signal. Sky Digital has been a major boost for many really remote spots though as it brought good quality reception of RTE1, NET 2, TV3 and TG4 to some of the islands off the west coast for the first time as well as a load of other channels that were simply unavailable as MMDS (Digital microwave terestrial tv) is pretty much line of sight!

Generally people use those rectangular flat panel wideband antennas but there are plenty of huge old yagi VHF aerials around too.

Sky's dishes are a nice neat sollution or MMDS flat panel antennas if you're in an area covered by the network.

Paul,
One thing you don't really see these days, is the old Test Patterns!.
I remember when I was a wee fella, TV used to close down quite early and a little man used to come on the TV and wish us all Goodnight(It was 7:30!) and that he hoped that we had enjoyed the evening's veiwing.
And then the test pattern would come on, until 10 am the next morning.
(If there was a guy doing this, these days,
his e-mail address would be worth having)
But with 24 hour TV, we don't have a close- down man (or a closedown either!), just Infomercials selling all sorts of useless rubbish.
What has the world come to?!.

RTE used to close down with the national anthem and spectacular shots of the Irish countryside including weird stuff like dew drops on a cobweb caught in the sunset ... followed by either pages from Aertel (Teletext) with one of the RTE radio networks in the background or a test card and either radio or just a high pitch tone going from left speaker to right speaker all night.

during the 1970s when they were on a shoestring budget (partly thanks to having to spend vast chunks of their tight budget on hosting the Eurovision song contest) Ireland's TV service didn't start until mid-afternoon as the station couldn't pay for programming!! Pretty high price to pay for a very crappy show, always thought it's an unfair burden to place on small broadcasters.

They just re-run their normal daytime programming during the night thesedays and I doubt the Eurovision would represent such a struggle these days.

I remember BBC closing down with the British national anthem too.

I think Austrian TV played the national anthem and then went to snowstorm all night. I once saw a recording of the German ZDF shutting down, there was some guy like the news guy, saying in a very official tone: "Now the Second German TV closes it's program" or something like that and then went to snowstorm.

Ah... Test cards with their accompanying light music. Far more entertaining and certainly of much greater value than the trash that fills daytime TV these days.

Back when I was a kid in the 1970s, neither the BBC nor ITV (Independent Television) ran 24 hours a day. A typical day's schedule for BBC started with the transmitters fired up at around 8 a.m. and line-up signals from 8:30 onward. I can still recall normal BBC start-up routine: Pulse-&-bar at 8:30, gray-scale at 8:40, and 50Hz signal at 8:50.

At 9 a.m. we would get the test card with music until the start of either: (a) schools programs or (b) test matches during the cricket season. It was back to test card until noon or thereabouts for the news and current affairs stuff, and a short item for the young kiddies. Then back to test card until children's programs at around 3:30 to 4 p.m. (unless cricket was still going!). In later years they started putting more on in the afternoons, but mornings were still pretty much empty, except during school holidays and weekends when they had more on. I watched many re-runs of old Laurel & Hardy films and the made-for-cinema Buck Rogers serials of the 1930s, along with other children's fare such as The Adventures of Champion, Lassie, etc.

The evening programs generally finished by about midnight, unless something special was going on. Closedown here also had the announcer saying something along the lines of "From all of us here at the BBC, we hope you've enjoyed watching. The time is now five minutes to twelve and we are closing down. Goodnight." Then it was "God Save The Queen" (which for those unfamiliar with the British National Anthem, is the same tune as "My Country 'Tis Of Thee") with the accompanying film, showing shots of pageantry such as the changing of the guard at Buckingham Palace or something similar, ending on the Royal Flag. A few minutes later it would be blank raster and tone, and the transmitters would be switched off about a half hour later.

ITV followed a very similar pattern, although the day's start-up varied slightly as a different ITV company served each region. At about 9 a.m. the test signals would switch over to a "transmitters in service" caption, along with an announcement such as "This is Thames Television broadcasting through the transmitters of the Independent Broadcasting Authority." Many regions had a short 30 to 60-second opening film depicting scenes around the local area.

It was all so civililzed compared to today's presentation style. Back then, they let you see the show right to the end of the closing credits, and tere was often a couple of seconds black and silence before the continuity announcer came on. Now, they shrink the closing credits of one program to talkover it and advertise and it's all done as though there isn't a second to spare.

Here's the test card that most Brits recognize immediately, as it was used from 1967 right up until testcards vanished from the screens thanks to 24-hour programming:


Go here to see more old British test cards, tuning signals, etc.




[This message has been edited by pauluk (edited 04-19-2003).]

The CBC in Canada shuts off from the end of programming after 1 or 2 AM, till 6 AM or so.
The terrestrial transmitters, after programming is discontinued, goes to a greeny grey-scal, then shut off, When they were fed with an analog satellite signal, you
could hear the DTMF codes used to control the transmitter.
If you receive CBC by satellite, you see the gren/grey bars all night.

I would guess that the Irish system of transmitters are controlled by some form of SCADA type system. I know RTE's transmission network as well as carrying 4 TV channels and 5 Radio networks on FM is also capable of linking studios and doing other 2-way communications. For example reports from corespondents can be fed back to their news centre through their network from studios all over the country. Radio and TV centres in Cork and Dublin etc can also be linked without resorting to satellite. Each transmitter site is linked by a microwave feed. I presume there's a transmitter control channel on the microwave network, I don't think the signals are carried in-band as DTMF tones.

RTE's digital terrestrial service which has yet to launch was tested with full two-way internet with a back channel carried over the transmission network. The set top boxes didn't need a phoneline they had full 2-way from the antenna on the roof.

It looks less and less likely that it will be commercially viable considering that we've already got a full digital terrestrial network on digital MMDS (Microwave around 2.49 Ghz ish) and any other terrestrial digital system would simply be duplicating this.

I did have a map showing the microwave links used by RTE in Ireland a few years ago, but I don't think I still have it.

As I recall, RTE also had a microwave link from somewhere in the northeast (Co. Louth, Co. Monaghan?) to their studio in Belfast. I assume that the RTE Belfast studio also had links to the BBC and Ulster ITV network as well.

I've lost track of who exactly controls what in Britain these days, but up until the early 1980s most TV distribution was by way of mixed microwave and coaxial systems leased to the BBC/ITV by the GPO.