UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Closed Thread
 
Thread Tools
Old 22nd Sep 2020, 2:46 am   #1
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,853
Default Non–TC/Teletext Trade Test Transmissions?

Hi!

This query refers to the non T.C./Teletext Trade Test Transmissions!

I used to switch the TV on to BBC2 in the morning hours before programmes started, and usually before school hours, and amongst the patterns I saw:–

a) Colour bars full–screen;
b) Full white raster;
c) V.I.T.S. full–screen;
d) Smooth ramp, white on left and black on right;
e) Half–white/half–black, split horizontally;
f) I saw on one rare occasion, a single small white dot in the centre of the screen on a black background, this was not a switch–off spot as there was a continuous tone accompanying it – I only ever saw this once!
g) Very coarse grid white crosshatch patterns, much coarser than customarily used for convergence;

Can anyone tell me about these – purposes, times, etc?

Have any other unusual patterns ever been seen besides these?

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!
Chris55000 is offline  
Old 25th Sep 2020, 1:26 am   #2
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: Non–TC/Teletext Trade Test Transmissions?

Full-screen VITS now there's an oxymoron!

Full-screen pulse & bar used to be seen occasionally.

A very early memory for me from the days when our set only received the single BBC TV channel, was seeing a black cruciform pattern on a white background, which I would learn much later were called "Art Bars". Art for artificial, as it was electronically generated.

If I can trust my memory from 60 years ago, I seem to recall there was always a tone on the accompanying sound when this patten was showing.
__________________
--
Graham.
G3ZVT
Graham G3ZVT is online now  
Old 25th Sep 2020, 1:44 am   #3
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: Non–TC/Teletext Trade Test Transmissions?

Now this would have been very cool to see at the time, and I was in the right area, but sadly our TV couldn't receive ITV at the beginning.
Attached Thumbnails
Click image for larger version

Name:	bellinglee-winterhill.jpg
Views:	211
Size:	84.5 KB
ID:	216377  
__________________
--
Graham.
G3ZVT
Graham G3ZVT is online now  
Old 25th Sep 2020, 7:18 am   #4
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
Default Re: Non–TC/Teletext Trade Test Transmissions?

Worth keeping just for the G9 callsign. Bet that exceeded 150W DC to the final valve...

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is offline  
Old 25th Sep 2020, 6:00 pm   #5
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: Non–TC/Teletext Trade Test Transmissions?

G9+3 were research & development licences, I was going to say quite separate from amateur radio... but I'm not so sure.

Look! our own Andy Emmerson (midshires) G8PTH. had one.

Click image for larger version

Name:	g9bup.jpg
Views:	151
Size:	60.4 KB
ID:	216412

from
https://youtu.be/BiXkHErNxC4?t=247
__________________
--
Graham.
G3ZVT
Graham G3ZVT is online now  
Old 25th Sep 2020, 8:13 pm   #6
AC/HL
Dekatron
 
AC/HL's Avatar
 
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
Default Re: Non–TC/Teletext Trade Test Transmissions?

That mast and transmitter was used for trade aerial alignment prior to some (or all?) ITA transmitters going live. I believe it was also used when the Emley Moor mast collapsed.
AC/HL is offline  
Old 27th Sep 2020, 8:00 am   #7
Oldmadham
Pentode
 
Join Date: Sep 2019
Location: Perth, Western Australia, Australia.
Posts: 199
Default Re: Non–TC/Teletext Trade Test Transmissions?

Quote:
Originally Posted by rambo1152 View Post
Full-screen VITS now there's an oxymoron!

Full-screen pulse & bar used to be seen occasionally.

A very early memory for me from the days when our set only received the single BBC TV channel, was seeing a black cruciform pattern on a white background, which I would learn much later were called "Art Bars". Art for artificial, as it was electronically generated.

If I can trust my memory from 60 years ago, I seem to recall there was always a tone on the accompanying sound when this patten was showing.
Most of the generators which generated VITS, would also produce them as a "full-field" signal.
The only Brit test signal I remember seeing was a sweep, in 1971 on "the Beeb", when I was in England for a while.

Meanwhile, back in Oz, at the ABW2 site, the Standard test signals we used in the early days were FF sawtooth from a Marconi generator, 50Hz squarewave & "bump tests" from that same genny, a video sweep signal from a Marconi "sideband analyser"(SBA), Pulse & Bar from a different generator, & occasionally either video sweep or sawtooth from a Fernseh PGM 75.

When we went to colour, we used a Tek148, which produced standard VITs either in their normal format, or as FF signals , FF sawtooth, 50Hz squarewave, as well as "bump" signals.
We used a newer Marconi SBA for sweeping the Tx.

Our old Marconi transmitters were "high level modulated", so the sideband analyser was most appropriate.
The "IF modulated" transmitters at other sites were usually tested with RF sweepers, instead, although when I went to the Private Sector, they still preferred the SBA, even with such Tx.

We did a full set of video & audio tests on both transmitter combined each Saturday morning, as the station didn't open till 12 noon.
Once a month, we did individual tests on each transmitter separately.

The PGM75 could produce other signals than the ones we used.
Before my time, they used line rate & higher rectangular pulses, but as they produced harmonics beyond the video passband, they had limited utility.
Oldmadham is offline  
Old 27th Sep 2020, 12:30 pm   #8
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: Non–TC/Teletext Trade Test Transmissions?

There was a tape of various moving and still scenes, some with graphical overlays, I think the footage was mute. It was used to evaluate the effect on real-world receivers of increasing the number of Teletext lines.

The same footage was used some years later when the sound carrier level was reduced, and NICAM data was was applied to the vision.
__________________
--
Graham.
G3ZVT
Graham G3ZVT is online now  
Old 30th Sep 2020, 1:37 pm   #9
Tazman1966
Nonode
 
Tazman1966's Avatar
 
Join Date: May 2006
Location: St Albans, Herts, UK.
Posts: 2,193
Default Re: Non–TC/Teletext Trade Test Transmissions?

When I was young (ages ago!) there used to be an order to the the test transmissions before test card F appeared at 9am. I think the order was half white/half black for 10 minutes, grey scale for 10 minutes, then the pulse and bar (full screen) for a further 10 minutes.

We were had the choice of three regions and Wenvoe sometimes did something different and had the smooth ramp grey scale you mention. I think this happened when BBC2 Wales had a different start up time to the network. Again, all this is from hazy memories form 40 or more years ago.

Does anyone remember also that the back to front greyscale (black on the left, white on the right) was occasionally transmitted without a sound carrier or vertical sync signal when the transmitter was first switched on? I assume this was transmitted directly from the transmitter.
__________________
All the very best,
Tas
Tazman1966 is offline  
Old 30th Sep 2020, 7:57 pm   #10
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,853
Default Re: Non–TC/Teletext Trade Test Transmissions?

Hi!

I also remember the "Test Card Memory Lane" site, now apparently defunct, mentioned the 'full screen VITS" test had black vertical identification lines on the left–hand side white bar that indicated what transmitter/region was radiating the test, but unfortunately I can't find this info online any more – can anyone help with more about this?

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!
Chris55000 is offline  
Old 30th Sep 2020, 8:25 pm   #11
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Non–TC/Teletext Trade Test Transmissions?

I remember a "Maltese Cross" type of test-card shown in the 'dark hours' - it was active in that it click-rotated about the centre-point over a minute, and the striations on the arms of the cross had microsecond-graduations so you could assess multipath reflections.

There was also a strange graticule-thing [imagine looking through several layers of chain-link-fencing, each adding its own colored fringe-refraction-patterns].

This was US 1960s NTSC. I spent some time in the DFW area with my parents, who regularly stayed up early/late to sync their phonecalls with the UK, and tuning-around-on-the-TV was kinda fun!
G6Tanuki is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 12:23 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.