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Radar Video & Sync Generator

 
freya
(@freya)
Noble V-Ratter Registered

Had this neat pattern / sync generator for a year or so with the intention of getting it usable again. Its been partially re capped at some point so that the divider stages are working and it does kind of produce the vertical and horizontal bars in a grid, it does no lock to the mains so its all floating about.

Before going into it further I really would like to find a schematic, nothing exists online so far.

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Also an extract from television Dec 1950, quickly re typed my me so excuse any obvious blinders.

"This particular instrument is known as the Radar Video and Sync Generator, not because it has anything to do with radio location, but because it is produced by a firm known as Radar, Radio and Television.
The instrument takes the design of the signal generator and pattern generator a stage further, and produces a fully synchronised test pattern which, in addition to the cross mesh of black bars, produces a shaded graduation in each case of the resulting white squares. When properly adjusted there thus appears on the picture tube two wide vertical bars, three horizontal thin bars, giving 12 white squares.

The upper edge of each square is darkened to the D.C. transmission level (30 percent) and fades up to peak white (100 percent modulation) at the bottom of each square. This latter feature enables the brilliancy and contrast controls to be set properly. The modulation circuits producing this tonal graduation are switched so that, if desired, they may be cut out and a blank synchronised raster left. The frame frequency in this test also locked to the mains and when the frame frequency or hold adjustment in the receiver is properly set the three black horizontal lines are steady. Faulty frame circuits will result in more or unsteady lines, and with the synchronising circuits provided it is even possible to check that interlacing is satisfactory. A switch is provided to "unlock" the frame sync from the mains and this of course, as previously mentioned, enables one to check for mains ripple or hum.

A further feature of this particular instrument is the sound output is provided so that one can also check whether there is "sound on vision" or vice versa, and thus it is possible to check every part of a receiver and adjust it outside of broadcast hours, leaving it in such a condition that the user can switch on when the programmes are being radiated with certain knowledge that it will not require any further adjustment. The time saved to service engineers by an instrument of this nature is, of course, obvious."

Stephen

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Topic starter Posted : 29/09/2019 6:05 pm
PYE625
(@pye625)
Famed V-Ratter Registered

An interesting device, looking forward to seeing how you get on with it. ?

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 02/10/2019 9:07 pm
Nuvistor
(@nuvistor)
Famed V-Ratter Registered

There wouldn’t be many service departments with one of those, my first pattern gen was a RBM 405/625 crosshatch gen for CTV work.
When I started work it was for a quite large a radio and TV business and had around 8 bench engineers, if one of these was available I never saw it. They had a signal generator and an AVO 8 on each bench, a shared oscilloscope, valve voltmeter and Mullard high speed valve tester.

I have looked for info on the Radar but no luck so far.

Frank

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Posted : 03/10/2019 7:10 am
turretslug
(@turretslug)
Reputable V-Ratter Registered

That is indeed an interesting and worthwhile find- it must have cost a small fortune in its time, I'm imagining that it would have had to be a significantly large servicing department to justify the outlay on something like this. I'll be intrigued to see how this turns out.

There's a sniff- just a sniff- of Gee about this device (WW2 low VHF hyperbolic navigation system principally aimed at airborne use- I don't think I'm being hyperbolic (!) in describing it as the grand-daddy of GPS) with its 5 position Band I front end, albeit TX rather than RX (are they acorn valves I see in there?) and its use of divider sequences to produce markers on a CRT display. There would have been a great many ex-Services techs who would have had strong familiarity with Gee and a plethora of other electronic devices at the time, I wonder if one of these people saw a relevance and opportunity post-war in designing a device for TV alignment based on their experience? The presentation has a sort of dour military functionality to it. Perhaps even someone involved in wartime design who saw a spin-off in TV use once things were settled. That might also explain the thinking behind choosing the name "Radar".

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Posted : 03/10/2019 9:08 am
sideband
(@sideband)
Famed V-Ratter Moderator
Posted by: @freya

Its been partially re capped at some point so that the divider stages are working and it does kind of produce the vertical and horizontal bars in a grid, it does no lock to the mains so its all floating about.

In the first picture I see a couple of those nasty 'torpedo' capacitors that look like fat resistors. Colour code of one suggests 3000pF, Can't see the other one clearly. They look like resistors and I'm betting that they are behaving like resistors...….

Interesting find. Awaiting with interest to see how it turns out.

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Posted : 03/10/2019 9:19 am
freya
(@freya)
Noble V-Ratter Registered

I started to draw the schematic and finished one side of the instrument, the other side however is much more complicated in the layout deciding which half of  a 6SN7 does what.

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Topic starter Posted : 03/10/2019 10:24 am
PYE625
(@pye625)
Famed V-Ratter Registered
Posted by: @sideband

In the first picture I see a couple of those nasty 'torpedo' capacitors that look like fat resistors. Colour code of one suggests 3000pF, Can't see the other one clearly. They look like resistors and I'm betting that they are behaving like resistors...….

I have a fetish with these....    After I have several, I line them up and take great pleasure in popping them one by one with a PSU !  ?

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 03/10/2019 11:40 am
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