NBTV Television Analyst

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Re: NBTV Television Analyst

Postby Harry Dalek » Sun Jul 26, 2020 8:34 pm

Managed something very minor to show even with the lid off and extra light noise ....the problem when i hooked the PMT circuit up today my finger in front of the CRT what has got me stumped so far is why the line and framing is drifting when i am using the same clock they should be locked .
Each CRT using its own ADC ramp generator i wonder if the delay is due to this some delay happening in the circuits mmmmm
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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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Harry Dalek
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Re: NBTV Television Analyst

Postby Klaas Robers » Mon Jul 27, 2020 12:51 am

Could it be possible that the external lighting, that scatters into the light path, is modulated with the mains frequency? This is not synchronised to your scanning. An open lightpath gives you a lot of unexpected results, that have nothing to do with the functioning of the system when closed. So close it and make yourself some simple test slides. Then experiment only in this set up.
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Re: NBTV Television Analyst

Postby Harry Dalek » Mon Jul 27, 2020 5:07 pm

Klaas Robers wrote:Could it be possible that the external lighting, that scatters into the light path, is modulated with the mains frequency? This is not synchronised to your scanning. An open lightpath gives you a lot of unexpected results, that have nothing to do with the functioning of the system when closed. So close it and make yourself some simple test slides. Then experiment only in this set up.


Hello klaas
I have already some simple slides ,they came up very faint i could just see them with the eye but light noise didn't help ...the transformer does worry me if it is picking up the mains frequency i am very close to the transformer so very possible ...it could be the case it might very well effect the PMT as well but more than likely the CRT .
The good thing about this side of it i can remove it from the problem area and test out side the case if you think the transformer is the cause ..

I think i will get a shoe box or just a box and test it a little away for the case cutting out that problem and take your advice and trying it in the dark .. should work out whats up then .

That will be later this week any case i know the CRT side of it works the pmt works ,i did hope to get some better results first day but not to be this project is making me work for the wanted results . :roll:
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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Harry Dalek
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Re: NBTV Television Analyst

Postby Harry Dalek » Thu Jul 30, 2020 5:45 pm

Having said what i did last post i had another think about the problem more and it comes down to more placement of the FSS CRT ,adjusting a size of a light indicator on the panel i was able to fit the Crt where i originally wanted it . raster seems ok but least now i can put the lid on it ..
See how this change go's tomorrow ,Hope the PMT is not effected by the transformer other wise another placement change .
Attachments
DSCN6890[1].JPG
DSCN6895[1].JPG
DSCN6897[1].JPG
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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Harry Dalek
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Re: NBTV Television Analyst

Postby Harry Dalek » Sat Aug 01, 2020 9:23 am

I have a light hole size for the PMT that works i am happy with to experiment with for now ...,i could start to see the test card slide last night which showed me the video is inverted .
And i have to match the raster aspect ratio sizes from FSS to monitor .
To small a hole for the PMT a higher negative voltage needs to be adjusted to it and there seems to be more noise in the image , larger hole less voltage less noise....Last portable PMT camera i used a 35mm lens focused to pmt face so all so i could adjust the light level on the lens its self and it needed no more than high 600s in low light tests i can't do that here so voltage and raster brightness control for the fss crt used on this one for that...
So getting there i will post up some pictures when i have fixed it up a bit more .
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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Harry Dalek
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Re: NBTV Television Analyst

Postby Harry Dalek » Sat Aug 01, 2020 9:27 pm

Today i experimented with the PMT hole size came down to a goldilocks idea not to large not to small .
best results so far twice the size of this hole if to large the pmt starts to over load but pretty much the voltage around the high 800's, if its a pin hole the voltage needed is much higher .
DSCN6904[1].JPG



i thought i had a better video but the first one seems to have recorded 2nd failed ...
Here on a pmt hole the video was about the above size for the recording ...i am not sure why the light difference on the darker NB to the TV on the test slide as you see when i move it has nothing to do with the raster position mmmm video is still inverted also still .
Edit i wonder if there's a slight distance of the slides bottom to the top to the crt might just tape it to the crt face and see
Attachments
DSCN6909[1]_x264.mp4
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DSCN6910[1].JPG
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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Harry Dalek
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Re: NBTV Television Analyst

Postby Harry Dalek » Sun Aug 02, 2020 4:03 pm

Well i am going to have to make a circuit change to invert the video its only just managing the hand drawn slides at the moment trying photo slides there's washed out details looking ..adjustments and such would be a lot easier with a slide non inverted .
Have think about where to go from here ...
Hard to see but thats a maltese cross in the middle NBTV letters side ways on the 4 sides see it a bit clearer towards the end of the video

Attachments
DSCN6926[1]_x264.mp4
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DSCN6917[1].JPG
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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Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4379
Joined: Fri Sep 26, 2008 4:58 pm
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