P7 Cop McDonald monitor(s).

Forum for discussion of SSTV topics. Slow Scan television (SSTV) is a picture transmission method used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or colour.

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Re: P7 Cop McDonald monitor(s).

Postby smeezekitty » Wed Sep 01, 2021 12:56 pm

Harry Dalek wrote:Oh and i am a young...un 1960

What does that make people like me born in the late 90s? O.o
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Re: P7 Cop McDonald monitor(s).

Postby Steve Anderson » Wed Sep 01, 2021 12:56 pm

Ah! Yes John, that makes sense. I didn't consider NBTV, how remiss of me! Hence the rather large values (1 or 2uF) capacitors feeding the deflection plates. For SSTV they would have to be immense and non-electrolytic, simply too much leakage current.

Using capacitive coupling as above is quite common for electrostatic CRTs where the deflection frequencies are fixed, unlike an oscilloscope where they are varied and often much slower. If you want a DC-coupled 'scope, they simply have to go, it makes the design more complex, especially with tubes/valves. The same applies to the grid/cathode video modulation, though some license can be taken there.

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Re: P7 Cop McDonald monitor(s).

Postby Steve Anderson » Wed Sep 01, 2021 1:00 pm

smeezekitty wrote:What does that make people like me born in the late 90s?

...er, responsible for carrying this on once we're long gone? (said somewhat tongue-in-cheek).

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Re: P7 Cop McDonald monitor(s).

Postby Harry Dalek » Wed Sep 01, 2021 5:00 pm

smeezekitty wrote:
Harry Dalek wrote:Oh and i am a young...un 1960

What does that make people like me born in the late 90s? O.o



HAHA i forgot about the later day younguns ! :D
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: P7 Cop McDonald monitor(s).

Postby Harry Dalek » Wed Sep 01, 2021 5:41 pm

Steve Anderson wrote:Thanks for the link Harry, the page has been added to since I last saw it. A useful resource to tuck away in your "Reference - Timebases" folder...

It appears we have a lot of knowledge and experience within those gathered here...

Steve A.


BTW here's another the main site love the projects ! Yes Steve that's a keeper i am studying to build a test circuit tomorrow
http://www.vk6fh.com/
http://www.vk6fh.com/vk6fh/NBTVmk3.htm
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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