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3rd Oct 2021, 10:17 am | #1 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
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The Mongrel Valve NBTV
HI all i am working on a valve low def Monitor this time 32 line baby steps for me with Valves hollow state tech !
I am happy with the input video inverter ,video amp, and 2 Phantastron time base oscillators ... I used the 2 Phantastron oscillators from this monitor Chris long made in the 70s nothing else from this circuit. I have used a few sync separator circuits only one with promise has been the transitron sync separator...but very touchy i am not sure but the phantastron oscillators are hard to sync and have to be set up every time and levels and such. Has any one got a NBTV Valve sync separator circuit the out put for the line looks messy but does sync the line oscillator the framing i am still working on . I am going to use it with a 3bp1 in time but working on the circuits here first before trying to hook up the CRT . |
3rd Oct 2021, 10:41 am | #2 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
The result of syncing the line is below not to bad when it behaves, but i have to adjust oscillators line frequency control close to the 400hz line frequency before it locks ..
I first tried this NBTV sync separator but it didn't seem to work so switched to the one in the last post . I am at the moment working on the deflection amplifiers using the circuit in the scope schematic or half of it at the moment with the signal input ,my understanding is its a push pull but to me it looks to me like its amplified sawtooth is to one set of deflection plates and the other is just voltage adjusted to move the display either side ? any case the one triode side amplified saw tooth side of the circuit works . i have a made a few monitors all transistor ic jobs so i am a bit of newy here learning to do it all again from scratch |
3rd Oct 2021, 11:05 am | #3 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
Hard to put all your thoughts in one post so here it go's the start of all this ,i always wanted to used some thing from my valve collection sitting unloved in 2 draws in my shed some useful ones for this shown below so it was always on my to do list to make a vacuum tube TV and baby steps make a NBTV one which i am used to /
i have a case for this project shown below ready but now am in 2 minds as to casing it just as a monitor , i really like this transformer be a pity to lock it away in my project not not being able to access the voltages for any thing else i fancy to build in the future ...i am thinking of putting in banana sockets making it a CRT or valve project power supply as well . |
3rd Oct 2021, 11:23 am | #4 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
Now to mounted the board you saw in above posts a little earlier ...the boards with circuits now but before i wanted to know how to mount them ,i didn't fancy the old way of mounting the valve sockets in metal case stuck with working with the case up side down and trying to drill large metal holes neat .!
Now simple matter of screwing in the boards one go once they work ,then just hook up controls at that stage. So now back to the future i am working on the circuits and the problems in the first posts any ideas welcome on the sync sep and or deflection amplifiers . |
3rd Oct 2021, 12:05 pm | #5 |
Octode
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,573
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Re: The Mongrel Valve NBTV
Hello there.
You peaked my interest in the NBTV with your comments on my Youtube channel. I am still working on the home made 405 line TV, but I did look at the forum you mentioned and could well venture into the field at some point. I have a few questions if I may? I have a Hackrf-one and found some software that I use called HackTV this can generate various narrow band systems: - 30-am = No colour, 12.5 fps, 30 lines, AM nbtv-am = No colour, 12.5 fps, 32 lines, AM as well as the system used on some of the Apollo missions, so I am hoping this can be used to test anything I may build later. Australia seems to be the centre for NBTV interest, is it used over amateur radio and how well does it match with the SSTV systems out there? Watching your project with interest. Stay safe. Adrian |
4th Oct 2021, 5:37 am | #6 | |||
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
Quote:
I think i have to have another go at a second 405 line CRT as a flying spot camera for a signal test card such ...i am not clever enough for standards converter and rather go old school which is more fun for me . Quote:
https://www.taswegian.com/NBTV/forum...enbtv&start=45 latest version can be found on this page no instructions but read the pages and it will sink in . Gary M older software here viewers and such for 32 60 line https://www.taswegian.com/NBTV/forum...hp?f=41&t=2745 And of cause Dom B NBSC which does many standards more so in colour http://authorityfile.co.uk/NBSC/Home/Downloads Steve Anderson has posts up on the Moon mission TV system may be of interest https://www.taswegian.com/NBTV/forum...php?f=8&t=3059 Quote:
https://www.youtube.com/watch?v=r2YY2jFVeHo&t=601s BTW if you are on FB my early television channel here https://www.facebook.com/groups/170508300223659 Adrian[/QUOTE] |
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4th Oct 2021, 9:13 am | #7 |
Octode
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,573
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Re: The Mongrel Valve NBTV
I have watched the video on Youtube a few times to get the gist of things. I am not on Facebook as I do not like the platform, but that's a personal preference.
Software I also find sometimes to be a bit restrictive as I run Linux (Ubuntu) and looks as though much of the software is Windows only based. I am sure there will be alternatives, just have to do some digging for it. Cheers Adrian |
4th Oct 2021, 11:14 am | #8 | |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
Quote:
There isn't to much Linux Software for NBTV some times you have to work with the devil to get what you want i think there's a fair bit of SSTV related software for that but NBTV mmmm Below out of interest are my other monitors The DEVIL,THE BEAST, THE BINOCULAR ...all pretty much multi system to some exstent ..i think its very limiting to make a CRT monitor to one system when it can do many . |
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14th Oct 2021, 5:09 am | #9 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
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Re: The Mongrel Valve NBTV
I was thinking it was time to hook the CRT up a 3BP1 but looks like i still have to learn more about the deflection side ! i was expecting better this shameful !
I really only have one axis deflection plate working either axis at the moment still this is pretty small ~ ! only good thing so far nothing blew up ! and it seems to be behaving, not that i can see to much yet but linearity looks ok This morning i had nothing even to power the CRT up so better than nothing and made no wiring mistakes which you sure find out soon enough at these voltages...got look on the bright side |
22nd Oct 2021, 11:14 am | #10 |
Pentode
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 213
|
Re: The Mongrel Valve NBTV
Results a bit better today still need to improve the deflection amplifier results but this where I am up to today.
https://www.youtube.com/watch?v=HDxzkl-d2y8 |