The Mongrel

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Re: The Mongrel

Postby Harry Dalek » Mon Aug 23, 2021 8:13 pm

Steve Anderson wrote:
All OK, though I think I'm going to need some help with sync separation and a few other matters, we'll see...that's if it has to be tube based, semis, no problem...


Is Jean-luc's circuit useable here with sync separation Steve ? i know its harder here doing it with Valves but it will sure be interesting to see how it works out .


One thing I have never done is a P7 CRT type SSTV monitor. I guess I should really do it so I can 'experience' what those in the 60s had to go through..
.

Yours a magnetic deflected or electostatic Tube Steve only tried it with a magnetic deflected tube on The Deep image monitor ,all i can say is do it it was once on my to do list as now this one ..better use of the tube than hiding away some where.

I have (so my last stock-check tells me), two DP7-5 CRTs, the same idea as P7 CRT and 3" diameter. Not as low voltage as a DG7-32 (DP7-32) but no real hassle either...as before with the DG7-32 NBTV monitors it'll be a hybrid.


Oh that answers my question electro static a lot easier to drive than the magnetic

The only thing I'm concerned about is the quoted line-width at 0.7mm which means you'll lucky to get maybe 100 lines of resolution...but then again the old 72-line DG7-32 didn't seem that bad, however, this is a step-up from that...

Steve A.

If I do go ahead with this it'll be in the SSTV section...anyway, I've got a bucket load of other stuff to do, so don't hold your breath!
[/quote]

Well mentioned before i got 240 lines on the tiny vcr139A but at a slow 1.5 sec frame rate so i think 7 or 8 sec slow scan tv on your tube i bet would be ok
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: The Mongrel

Postby Steve Anderson » Tue Aug 24, 2021 4:11 pm

Harry Dalek wrote:...before I got 240 lines on the tiny vcr139A but at a slow 1.5 sec frame rate...

That is true, but there's no chance of the resolution (spot size) being able to resolve that. If no-one told you, you probably wouldn't notice the difference at 120 lines. Much like the grain in film, the bigger the grain, the more sensitive the film, but poorer in resolution/sharpness. A compromise as ever...

I'm mulling over this P7 SSTV monitor...I could use the 3" DP7-5 that I mentioned yesterday, or go for broke and use a 5" 5ADP7 (Euro version, DP13-34, of which I also have two). The 3" CRT only needs 900V, the 5" one, 3000V + 1500V. (Or 4000V + 2000V) Aside from that the rest is very similar, and I already have the metalwork done for both.

The 3" version is comparatively easy, but no push-over, the 5" more of a challenge...decisions, decisions...

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Re: The Mongrel

Postby Steve Anderson » Tue Aug 24, 2021 5:07 pm

OK, decision made...the 5" version it is. Digging through files/drawings I created well over a decade ago it's almost ready to go, though likely I'll change some aspects of it...e.g. PWM grid modulation over analogue. I could use tubes in some parts but I'm still undecided about that. This isn't going to happen 'tomorrow', but keep an eye on the SSTV section on this forum if interested...no more of this in this thread...let Harry continue on with his pursuit..

Steve A.

Harry, I have to say, from here onwards with this (your) project I'm out of my depth. I really have little (zero) experience with tubes/valves at this level, and then adapting the circuits to NBTV. I hope others will jump in and assist...
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Re: The Mongrel

Postby Harry Dalek » Tue Aug 24, 2021 5:48 pm

Steve Anderson wrote:That is true, but there's no chance of the resolution (spot size) being able to resolve that. If no-one told you, you probably wouldn't notice the difference at 120 lines. Much like the grain in film, the bigger the grain, the more sensitive the film, but poorer in resolution/sharpness. A compromise as ever...


Reason i wanted to also try it on the larger Beast Screen ,if i could set them up against each other might see it for sure it must work better on a larger screen ,still results were not to bad on the VCR139A

I'm mulling over this P7 SSTV monitor...I could use the 3" DP7-5 that I mentioned yesterday, or go for broke and use a 5" 5ADP7 (Euro version, DP13-34, of which I also have two). The 3" CRT only needs 900V, the 5" one, 3000V + 1500V. (Or 4000V + 2000V) Aside from that the rest is very similar, and I already have the metalwork done for both.


I would use the larger Tube , the high Anode voltage i got over 3Kv with a Cockcroft-Walton” voltage multiplier on The Beast as with your design just add another stage till you get what you want .

The 3" version is comparatively easy, but no push-over, the 5" more of a challenge...decisions, decisions...

Steve A.

Must admit i have never seen a small tube version of a p7 SSTV but if you are going to make on go classic i say .
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Re: The Mongrel

Postby Steve Anderson » Tue Aug 24, 2021 6:13 pm

Harry Dalek wrote:...I got over 3Kv with a "Cockcroft-Walton” voltage multiplier on The Beast as with your design..

I've got a few 240-500V isolated transformers I picked up here in Bangkok some years ago. Standard rectification will yield 700V or so. doubled to 1.4kV, two of them to 2.8kV, getting there...anyway, new thread time...

..one other problem may be getting diodes with a suitable PIV rating, I'm not so keen on a bunch of 1N4007s in series...

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Re: The Mongrel

Postby Harry Dalek » Tue Aug 24, 2021 6:34 pm

Steve Anderson wrote:OK, decision made...the 5" version it is. Digging through files/drawings I created well over a decade ago it's almost ready to go, though likely I'll change some aspects of it...e.g. PWM grid modulation over analogue. I could use tubes in some parts but I'm still undecided about that. This isn't going to happen 'tomorrow', but keep an eye on the SSTV section on this forum if interested...no more of this in this thread...let Harry continue on with his pursuit..


One of those things does not have to be made in a day but you have to keep your interest and be determined its a keeper :wink:
I will watch with interest off cause
I suppose you could use your old Brute case if it still exists ...i am a big one for recycling !

Steve A.

Harry, I have to say, from here onwards with this (your) project I'm out of my depth. I really have little (zero) experience with tubes/valves at this level, and then adapting the circuits to NBTV. I hope others will jump in and assist...
[/quote]

That's OK Steve the help with the Transformer was a big step very helpful here ,its not an easy one or any thing i have ever tried either as with the Beast CRT project i pretty much had no idea how it would end up a step at a time it came together ,gives you more confidence the more you try these things .

Only thing on Television with valves i have ever made was a 2 tube VHF FM radio to pick up local WIN tv in the 80s , this is a bit different .

Since this is going to be experimental i have to take into account i don't know everything and copy my approach to The Beast a little step leads to another i know what needs i just have to make it work .
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: The Mongrel

Postby Steve Anderson » Tue Aug 24, 2021 7:42 pm

Harry Dalek wrote:I suppose you could use your old Brute case if it still exists ...i am a big one for recycling!

Yes, it still exists, though very dull in appearance, could do with a high-pressure water jet as a minimum...be jiggered if I'm going to sand it down by hand!! Though to be honest I don't need that amount of real-estate for this...we will see...my thinking in those days was more horizontal rather than vertical...OK, let's just say I've moved on from those days...

Steve A.

Here's an example of 'cramming'...
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Re: The Mongrel

Postby Steve Anderson » Tue Aug 24, 2021 8:38 pm

Harry Dalek wrote: ...and be determined its a keeper

Nothing I ever do is a 'keeper', I move on and discard what I've done before, sure I document it, and that's enough. Done once, fine, twice is boring...

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Re: The Mongrel

Postby Harry Dalek » Tue Aug 24, 2021 11:51 pm

Steve Anderson wrote:
Harry Dalek wrote:I suppose you could use your old Brute case if it still exists ...i am a big one for recycling!

Yes, it still exists, though very dull in appearance, could do with a high-pressure water jet as a minimum...be jiggered if I'm going to sand it down by hand!! Though to be honest I don't need that amount of real-estate for this...we will see...my thinking in those days was more horizontal rather than vertical...OK, let's just say I've moved on from those days...

Steve A.

Here's an example of 'cramming'...


Well that idea i did that in the devil monitor small is better and cram it all in the case that was vertical but with external power supply, horizontal is also a way to go for me up to what you like i suppose personal preference and what case you can find or have handy

old case you can always spray paint it quick fix .

As for Keeping it depends on how well it works ,i have very little on the mechanical project side tends to warp of unglue in our summer heat over the years ,more success with ageing on the electronic projects .

Nice to have some thing that worked well to look back on documenting it on the forum is almost as good as still owing what ever you made .
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: The Mongrel

Postby Steve Anderson » Wed Aug 25, 2021 4:28 pm

Harry Dalek wrote:As for Keeping it depends on how well it works..

To an extent yes, but for me it's 'how useful is it?'. Not having a license here (nor do I intend to get one) there's little point in keeping completed hardware. It lives on in the documentation or publications it may appear in...which includes this forum.

A variable bench power supply is useful and they tend to stay intact. Whereas a NBTV/SSTV monitor may not. However, the "One-Inch Wonder" is still untouched...rather surprisingly...
Harry Dalek wrote:Nice to have some thing that worked well to look back on documenting it on the forum is almost as good as still owing what ever you made .

Being wholly dependent on one site to store your 'product' is risky, they come and go. OK, you've got your own drive at home, but any back-up? I have a NAS (Network Attached Storage) where if one of the five drives fails, all can be recovered with the remaining four. So far (fingers crossed) it's not happened..

An alternative is 'Dropbox', I think 1GB of storage for free, any more and you pay for it...actually, the free account is 2GB these days...but the caveat there is you need an Internet connection, not always possible...and 2GB isn't exactly a lot these days...my 'ATV' folder is over 18GB alone...

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Re: The Mongrel

Postby Harry Dalek » Wed Aug 25, 2021 5:56 pm

Steve Anderson wrote:To an extent yes, but for me it's 'how useful is it?'. Not having a license here (nor do I intend to get one) there's little point in keeping completed hardware. It lives on in the documentation or publications it may appear in...which includes this forum.


Documenting it on the forum is good showing proof of concept for sure ,hope it lasts go's on and on i would hate it if all this was deleted one day .
If it works and made it well enough its a keeper because i wanted it to the point of having to make something from scratch ,Proof of concept is ok most things for an experimental device .

A variable bench power supply is useful and they tend to stay intact.


Oh for sure most supplies are always kept till they brake regulator or transformer go's .

Whereas a NBTV/SSTV monitor may not. However, the "One-Inch Wonder" is still untouched...rather surprisingly...


I still have the Anderson monitor where looking at it now i know how to pretty it up panel wise casing so it might get recycled into a better version to improve its construction more than its workings .
Yes i was thinking you had kept that one well its small and unique !

Being wholly dependent on one site to store your 'product' is risky, they come and go. OK, you've got your own drive at home, but any back-up? I have a NAS (Network Attached Storage) where if one of the five drives fails, all can be recovered with the remaining four. So far (fingers crossed) it's not happened..


I don't know could down load some pages ,i recall about 10 years ago i came across software that could down load a site every thing but this must be many gigabyte's now but very possible on the large Hd's these days even the forum its self looses information i come across pages where links are gone photos gone so even here there is loss.[/quote]


An alternative is 'Dropbox', I think 1GB of storage for free, any more and you pay for it...actually, the free account is 2GB these days...but the caveat there is you need an Internet connection, not always possible...and 2GB isn't exactly a lot these days...my 'ATV' folder is over 18GB alone...

Steve A.

A site software download should do it as a just incase scenario ,HTTRACK seems the best here have to give it a go ! save the forum !
https://dynomapper.com/blog/11-content- ... ne-viewing
Last edited by Harry Dalek on Wed Aug 25, 2021 6:04 pm, edited 1 time in total.
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: The Mongrel

Postby Steve Anderson » Wed Aug 25, 2021 6:01 pm

Now I have a rather boring project to do, a couple (or a dual) bench power supplies. The two I bought in Hong Kong maybe 30 years ago, they were 'OK', just, but they did the job. I fried one a couple of months ago when I miss-connected the car battery to recharge it...easy to do...goodbye!!

Being sane (unusual) all I need the vast majority of the time is 0-15V at (say) 1A, both +ve and -ve. LM317s spring to mind instantly. Add (perhaps) a few fixed output voltages as well, say +3.3V and +5V for logic and microprocessor stuff, at around the same current, 1A. If you need more than that you're going to have to build that supply anyway, so you might as well get on with it!

The fixed output voltages are easy, 78xx, 79xx, given enough heatsinking. The variables are a challenge. There are many, many published designs 'out there' but many have limitations...protection (as I experienced) often being lacking.

More anon...

Steve A.

I may start a new thread on this as it's so fundamental to what we do here...without a reasonable power supply (PSU) you're in trouble...
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Re: The Mongrel

Postby Harry Dalek » Wed Aug 25, 2021 6:07 pm

OH your projects are not boring Steve ...keeps you busy mind food !
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: The Mongrel

Postby Harry Dalek » Sat Aug 28, 2021 11:55 am

After work yesterday i went to work on the project and found the DG7 with a large crack across the screen still mounted where it was ! very upsetting i have no idea why it was fine the day before ,i was thinking one of the kids had bumped it or dropped t but every one is saying no to this ,so i have to have a think about where to go next ,the tubes never been used very disappointing !
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Re: The Mongrel

Postby Steve Anderson » Sat Aug 28, 2021 12:32 pm

Ooops! These things can happen, and often do. Oh well, that one's for the bin. You can see air has got in by the 'getter' turning white near the tube base.

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