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A couple of CRTs ideal for SSTV

PostPosted: Sat Mar 25, 2017 8:46 pm
by aussie_bloke
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 :) .

(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 , 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.

(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.

Re: A couple of CRTs ideal for SSTV

PostPosted: Sun Mar 26, 2017 1:47 am
by Andrew Davie
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.

Re: A couple of CRTs ideal for SSTV

PostPosted: Sun Mar 26, 2017 12:52 pm
by Steve Anderson
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.

Re: A couple of CRTs ideal for SSTV

PostPosted: Sun Mar 26, 2017 7:09 pm
by Harry Dalek
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 !