Advance UHF Millivoltmeter VM 79

[camallison]

Alan, a long shot, but you might find a manual for it here:

http://servicemanualslibrary.com/

Colin

[camallison]

Found a source! A long way down this page http://www.divdev.fsnet.co.uk/man.htm

He DOES list the VM79 - looks as though you need to email him and then request a snail-mail copy.

Colin

[AlanBeckett]

Colin,

That's Mauritron, which was one of my early Ports of call. They're generally very good if not cheap, but unfortunately not this time.
However, I'll email them just in case their List isn't up to date.

Alan

[Alan Douglas]

For what it's worth, that manual is listed at the bottom of this page:

http://www.divdev.fsnet.co.uk/man.htm

Oops, I've been beaten to the punch. That's what I get for taking a moment to vacuum this rug. Let's try another tack. This forum discussion might be useful regarding the probe, and also has a link to a web page with Boonton probe information:

http://www.antiqueradios.com/forums/view...8&t=244495

[camallison]

Message to AD - now I'll get on with my vacuum cleaning!

It was certainly buried deep, but at least our two minds worked in concert.

Colin

[camallison]

Colin,

That's Mauritron, which was one of my early Ports of call. They're generally very good if not cheap, but unfortunately not this time.
However, I'll email them just in case their List isn't up to date.

Alan

See my (later) post as regards a positive sighting.

Colin

[AlanBeckett]

Thanks Gents, I knew you'd find it if it was there
I'm notoriously incompetent when it comes to searching.
I've emailed him for a price.
Mauritron haven't got it.

Alan

[camallison]

Each to their own Alan - I couldn't fix the VM 79 even if I had the manual and schematic in front of me!

Colin

[AlanBeckett]

Colin,

I don't know whether I can until I get the Manual

The Link to the Boonton Probes is interesting. I particularly liked the construction method using Copper Pipe - just my line, although I'd probably throw a bit of Turning in there.

Alan

[Skywave]

The Link to the Boonton Probes is interesting. I particularly liked the construction method using Copper Pipe - just my line, although I'd probably throw a bit of Turning in there.

Yes, I can see the reasoning to that. You have rough idea of the freq. whose amplitude you want to measure, but at the same time, you want to be sure that you're measuring the amplitude of that signal, and not have an erroneous measurement made on account of any unwanted signals and noise, etc. But any such tuning will have to be before the a.c, to d.c. conversion (obviously) and since your VTVM is alleged to go up to 500 MHz, at UHF, a tuning arrangement with a high input impedance and also something that isn't large and cumbersome will present a formidable design challenge. And then there is question of calibration to consider. Obviously, at lower freqs. - say up to about 30 MHz - that design requirement becomes a lot easier. So there is some room there for a design approach, dependent on your anticipated need, frequency-wise.

Al.