ITV Channel 11 Test Transmitter.

[Murphyv310]

Hi.
I've been given a Test transmitter from the 405 line era that produces vision on Ch11. I'd suspect it was made late 60's or early 70's. It has a 5 transistor carrier generator, diode ring modulator and a square wave oscillator which I don't know its use. The unit works perfectly and the quality is outstanding, also it's output is about 10 times that of an aurora.
I'll post a few pics later, I would like to know what it would have been used for.

[Refugee]

What frequency is the square wave?

[Murphyv310]

               
Hi.
The square wave is actually produced for a DC to DC converter to supply 15v to an external output, its not used in the unit.
Here are some pictures and a screen shot from the Imogen to the unit and to my Philips TVette.

[pwdrive]

That looks like a Tvette...

Lawrence.

[Murphyv310]

It sure is Lawrence.
I'd really like to find out more regarding the "test transmitter", where and for what it was used, it's specs, age, circuit and how many were actually made.

[Refugee]

It looks like a plug in from a much larger unit with many other plug in sections.
.

[Murphyv310]

It most likely is Ref. I'd think there is also a sound generator, also a vestigial filter, something to add both carriers, a possible PA stage and PSU. 
Perhaps Brian or Jeffrey may be able to help.

[ppppenguin]

Has a Marconi feel about it looking at the pics.. As Ref said, it's obviously a plug-in unit, likely from some larger system. Possibly CATV/MATV?

[Brianc]

It is definitely built like a battleship. The TO5 transistors are on their heads to reduce vibration damage. Also, decent tantalum caps are used and these, in their day, were incredibly expensive. This all suggests long term unattended working such as CATV etc. A lovely piece of kit - if you ever get a CH1 unit, could I have it Trev?

[Murphyv310]

Hi.
David Higginson (Hamish Boxer) has one I believe, in working order too!