Magnetic amplifier

[gary]

And, of course, I hope it hasn't passed anyone's notice, that by implementing this method Baird also invented "Digital TV"

[AncientBrit]

Hi Gary,

My reference to the book was the image 75119959.3.jpg posted further up the page.
EDIT. I needed to zoom in a bit to read the page. Age and all that!

I'm still not convinced about the ability to improve the tardy response of a cell by chopping the light.

Sorry,

Cheers,

Graham

[gary]

Don't be sorry Graham, I merely present issues I thought you may have missed - I am not trying to convince anyone of anything. With regard to the wireless world reference I feel the two patent references give a better insight on what he was trying to achieve.

[AncientBrit]

Thanks Gary, I'll look them up.

Cheers,

Graham

[gary]

Since I happened to have both of them up (checking myself - one has to do that at my age) - here they are:

http://www.taswegian.com/NBTV/forum/viewtopic.php?t=226
http://www.taswegian.com/NBTV/forum/viewtopic.php?t=227

Thanks to Stephen Mican for posting them.

(I wonder what happened to him? - give us a shout Stephen if you are still about).

[Harry Dalek]

Well i am getting my first idea together for the oscillator really going on to other steps depends on if i can get this to work at all and if i can get a nice frequency for the mechanical tv band width .

One thing on the last few posts on Bairds second disk how did he keep the thing from drifting i expect drifting i can only think he used battery power still once that drops it would still be as bad as a poor Ac supply ours now gos up and down by a few volts .
Or did it matter ? i expect drifting but i am not sure if it will effect the video much if its kept with in a correct range ...

What i hope to try with this disk is a reflective sensor idea that they could of done in the late 1880s motor filament light bulb and a light sensor either a disk with holes or as i am doing reflective if it works... i am going to try a LDR connected to a small voltage to see if i can get the ac nice and simple ....

[gary]

I PROMISE this will be my last post on the subject of the Falkirk transmitter serrated disk, this is an excerpt from "Television, an international history of the formative years" by one of our past NBTVA presidents R. W. Burns.

[Harry Dalek]

I PROMISE this will be my last post on the subject of the Falkirk transmitter serrated disk, this is an excerpt from "Television, an international history of the formative years" by one of our past NBTVA presidents R. W. Burns.

It isn't really talked about much so a good chat on that light chopper is a good learning thing ...

Going off the topic this advert i think for headache tablets i can see a few mistakes on the fake Baird machine.

No wonder he has a headache

[gary]

One thing on the last few posts on Bairds second disk how did he keep the thing from drifting i expect drifting i can only think he used battery power still once that drops it would still be as bad as a poor Ac supply ours now gos up and down by a few volts .
Or did it matter ? i expect drifting but i am not sure if it will effect the video much if its kept with in a correct range ...

That's a pretty good question Harry, Baird would have had access to synchronous motors, probably more so than we do today, yet I doubt he did that for the serrated disk.

For the purpose of his exercise I doubt he worried too much about the speed unless it adversely effected his "first differential" (i.e. the magnetic response of the transformer) - If he demodulated his signal with a synchronous chopper demodulator then he would just have used the other side of the serrated disk (presumably).

(I know the previous was supposed to be my last post on the Falkirk tx but this is really an answer to a mag amp question.)

In your case Harry I fear that you will be so beset with phase errors and magnetic non-linearities I doubt that it will matter too much in your case either - but if you are concerned about it as regards my challenge then if it works with a xtal locked oscillator but not with a serrated disk (due to speed issues) I would concede and crown you winner .

In addition, and to make things easier, I would also allow the source of the video signal to be a non-mechanical source (cd player pc etc) PROVIDED that the signal is demonstrably amplified by the order required in pre-valve days and plays reasonably well on, say TBP?

A committee needs to be assembled to ascertain what the order of amplification should be

Oh and when you have completed the mag amp task we can start on the selenium cell (or whatever) response time problem.

[gary]

Clever ad that Harry

BTW with your encoders I presume you will NOT be using an IR sensor? otherwise how are you getting around your laser printer problem? That's a LOT of cutting out if you use your normal method.

BTW my investigation of that problem has caused quite a stir on the HP printer forum as every one agrees it is just a ploy by HP to waste colour ink - they certainly haven't denied it.

[gary]

Oh BTW Harry I forgot to mention that you could conceivably design an encoder disk with segments so shaped as to produce a sine wave which would reduce your harmonics considerably - perhaps best left until you get something working.

[Harry Dalek]

Hi Gary
Back on line just answer in a tick

[Harry Dalek]

That's a pretty good question Harry, Baird would have had access to synchronous motors, probably more so than we do today, yet I doubt he did that for the serrated disk.

Doing a lot of manual motor control you tend to get use to adjusting readjusting things just a touch i was thinking he might of been doing that but its one experiment i have not tried and i am not sure if it would effect in the same way in as in hes mechanical chopper, but adjust the PWM clock frequency so change the band width in that type of display circuit.

For the purpose of his exercise I doubt he worried too much about the speed unless it adversely effected his "first differential" (i.e. the magnetic response of the transformer) - If he demodulated his signal with a synchronous chopper demodulator then he would just have used the other side of the serrated disk (presumably).

I have not seen any thing on the other side of that disk so perhaps the first answer ...

(I know the previous was supposed to be my last post on the Falkirk tx but this is really an answer to a mag amp question.)

Well its the same sort of thing light choppers and it is my thread so you can answer much as you like on both versions.

In your case Harry I fear that you will be so beset with phase errors and magnetic non-linearities I doubt that it will matter too much in your case either - but if you are concerned about it as regards my challenge then if it works with a xtal locked oscillator but not with a serrated disk (due to speed issues) I would concede and crown you winner .

I am interested to see the frequency and waveform...i think it will be a bit like controlling a manual nbtv picture ,i didn't think of it before on the waveform but this with a photo trany is a sine wave wonder if its the same on the LDR
Trying to keep it simple with all the issues of simple my other idea of an early clock type would be the carbon arc oscillator not some thing i want to try in the house

In addition, and to make things easier, I would also allow the source of the video signal to be a non-mechanical source (cd player pc etc) PROVIDED that the signal is demonstrably amplified by the order required in pre-valve days and plays reasonably well on, say TBP?

If i get as far as doing the amp i wanted to try a test we did like the head amp led test a nbtv wave file being transmitted via a LED via the pc sound card ....being received by another LDR or solar cell then via the magnetic amp and out put recorded so we can sort of can tell with out the mechanical disks for camera monitor if the electrics in this case work in best case ..

A committee needs to be assembled to ascertain what the order of amplification should be

the guy on the you tube amp test says you get around 2000 X if you use diodes in hes magnetic amp circuit .

[quote]Oh and when you have completed the mag amp task we can start on the selenium cell (or whatever) response time problem.[/quote[/

I was looking up these things you can find them in old cameras and old light meters i bet i have a few of those in the shed think its the only place any one can track them down these days in old cameras.

[Harry Dalek]

Clever ad that Harry

BTW with your encoders I presume you will NOT be using an IR sensor? otherwise how are you getting around your laser printer problem? That's a LOT of cutting out if you use your normal method.

BTW my investigation of that problem has caused quite a stir on the HP printer forum as every one agrees it is just a ploy by HP to waste colour ink - they certainly haven't denied it.

Thats right Gary i am just trying normal light this time Old filament light bulb LDR see how it gos .

Well next time i buy a printer it will not be HP lets hope it does not have the same effect on normal light MY luck !

[Harry Dalek]

Oh BTW Harry I forgot to mention that you could conceivably design an encoder disk with segments so shaped as to produce a sine wave which would reduce your harmonics considerably - perhaps best left until you get something working.

This is what i get with the encoder disk for nbtv motor control and the photo trany i didn't really ever think about it but before all this if you asked me i would bet i would of got a square wave .
Do you have an example or link to see the shape out of interest.

I have a fair few disks to test i had one with round dots instead of stripes the number of those on these strobe disks i am not sure about what is the minimum number i could get away with the 400 + one i had was to much for my printer or it was to low in quality to print out so the 200 slot one was best for that type ...the one i am using testing looks good for my light reflecting size