A couple of CRTs ideal for SSTV

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.

Moderators: Steve Anderson, Dave Moll, Andrew Davie

A couple of CRTs ideal for SSTV

Postby aussie_bloke » Sat Mar 25, 2017 8:46 pm

G'day all. I've accumulated a bit of a collection of CRTs over time and a few of them are long persistence good for SSTV. I was talking to Harry about them as he's playing around with SSTV lately and he suggested I share them to this forum so here's some photos of my long persistence CRTs.

The first one is a Philips DP7/32 which came from an Australian made cardiotrace ratescope heart rate monitor that was recently given to me. I read they are very rare so am lucky to have one :) .

dp732.jpg
(998.7 KiB) Not downloaded yet


The second one is a very large VCR140 magnetic deflection radar CRT, I actually have two of them, I got them tubes with a late 1940s American Andrea T-VJ12 B&W television chassis http://troysvintagevideo.0catch.com/andrea.html , believe it or not those tubes were used with this set, this set and the tubes were probably used television training courses in Australia in the early 50s leading up to the introduction of television. Anyhow this tube has a different number inscribed on it which I can't find on Google but it should be a VCR140 equivalent.

vcr140.jpg
(1.63 MiB) Not downloaded yet


Anyways those are my tubes. I do intend on building a SSTV somewhere down the line, will start with making a small one with the DP7 and later on a large one with the VCR140.
aussie_bloke
Just nod and pretend you understand me
 
Posts: 211
Joined: Sat Apr 28, 2012 7:48 pm
Location: NSW, Australia

Re: A couple of CRTs ideal for SSTV

Postby Andrew Davie » Sun Mar 26, 2017 1:47 am

My local recycle shop still has a number of CRT tubes (small, beautiful) essentially new in box for around $35 each.
So if you're looking for one or two let me know.
User avatar
Andrew Davie
"Gomez!", "Oh Morticia."
 
Posts: 1508
Joined: Wed Jan 24, 2007 4:42 pm
Location: Hobart, Tasmania, Australia

Re: A couple of CRTs ideal for SSTV

Postby Steve Anderson » Sun Mar 26, 2017 12:52 pm

The DP7-32 is an ideal CRT for a first SSTV monitor construction. By CRT standards it's quite a low-voltage tube. The power supply would need to provide around +300V for the deflection amps and the final anode as well as around -600V for the grid/cathode circuitry. Beam modulation is easily done via an opto-coupler whether linear or PWM.

Due to the very slow speeds involved virtually every stage within the device needs to be DC-coupled. It's no major issue but needs be thought about at the design stage.

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 3800
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: A couple of CRTs ideal for SSTV

Postby Harry Dalek » Sun Mar 26, 2017 7:09 pm

Yes great Crts Troy the small one as Steve mentioned would make a great little monitor !
But i must admit i would love also to see the big one as a Slow Scan television i know its not really practical but it would be the largest ever !
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4045
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia


Return to SSTV

Who is online

Users browsing this forum: No registered users and 1 guest

cron