On 19/02/2014 09:32, gareth wrote:
"AndyW" wrote in message
...

(but then I enjoy retro-tech like making Baird televisors)


Mirror-drum, or Nipkow disk?

Nipow disk. I built my first one while at school using plans in Hobby
Electronics using my sister's 'The Partridge Family Album' LP, I thought
that it was the best use that it could be put to; she disagreed.

One of my later ones used a 'conveyer belt' instead of a disk which
produces a square screen.

LED or nitro-benzine as the polariser?

Polariser?
I used a neon as my light source, I didn't have any polarisation.
My later ones use LEDs at light sources and produce a much better
quality of image.

Andy

"AndyW" wrote in message
...
On 19/02/2014 09:32, gareth wrote:

LED or nitro-benzine as the polariser?
Polariser?

To my eternal regret, because I disposed of them 38 years ago, I had a
pile of "Amateur Wireless" from the 1930s within which were designs
for mirror-drum scanners, and the modulation was not by a neon light
but with a constant light source which was then modulated by a series
of polarising filters, with one being variable to rotate the polarisation.

ISTR (38 years ago!!!) that the liquid used was nitro-benzene

On 20/02/2014 11:51, gareth wrote:
"AndyW" wrote in message
...
On 19/02/2014 09:32, gareth wrote:

LED or nitro-benzine as the polariser?
Polariser?

To my eternal regret, because I disposed of them 38 years ago, I had a
pile of "Amateur Wireless" from the 1930s within which were designs
for mirror-drum scanners, and the modulation was not by a neon light
but with a constant light source which was then modulated by a series
of polarising filters, with one being variable to rotate the polarisation.

ISTR (38 years ago!!!) that the liquid used was nitro-benzene

OK I follow you now. I had a quick google and found out about
nitrobenzene and modulating polarisation. Never heard of it before. Live
and learn.

My original set up was as simple and agricultural as they come, vinyl
LP, scrap motor from a cassette player, Neon attached to am amplifier
behind the 'screen' and a camera made from a lens and an LDR recording
onto a cassette player - the bandwidth was low enough to record on audio.

My latest televisor was made from a circle of black plastic spinning on
a hand fan with a very small torch behind it modulated by the sound from
a small mp3 player. It all folds up and fits in a pocket.

Andy

"AndyW" wrote in message
...
On 20/02/2014 11:51, gareth wrote:
"AndyW" wrote in message
...
On 19/02/2014 09:32, gareth wrote:
LED or nitro-benzine as the polariser?
Polariser?
To my eternal regret, because I disposed of them 38 years ago, I had a
pile of "Amateur Wireless" from the 1930s within which were designs
for mirror-drum scanners, and the modulation was not by a neon light
but with a constant light source which was then modulated by a series
of polarising filters, with one being variable to rotate the
polarisation.
ISTR (38 years ago!!!) that the liquid used was nitro-benzene
OK I follow you now. I had a quick google and found out about nitrobenzene
and modulating polarisation. Never heard of it before. Live and learn.
My original set up was as simple and agricultural as they come, vinyl LP,
scrap motor from a cassette player, Neon attached to am amplifier behind
the 'screen' and a camera made from a lens and an LDR recording onto a
cassette player - the bandwidth was low enough to record on audio.
My latest televisor was made from a circle of black plastic spinning on a
hand fan with a very small torch behind it modulated by the sound from a
small mp3 player. It all folds up and fits in a pocket.


Wow! How many lines and frames / sec?

"gareth" wrote in message
...

Wow! How many lines and frames / sec?


A quick google yielded ...

http://www.tvhistory.tv/1935%20TV%20...20Part%202.htm


.... and look for "Kerr Cell"

On 20/02/2014 15:08, gareth wrote:
"AndyW" wrote in message
...
On 20/02/2014 11:51, gareth wrote:
"AndyW" wrote in message
...
On 19/02/2014 09:32, gareth wrote:
LED or nitro-benzine as the polariser?
Polariser?
To my eternal regret, because I disposed of them 38 years ago, I had a
pile of "Amateur Wireless" from the 1930s within which were designs
for mirror-drum scanners, and the modulation was not by a neon light
but with a constant light source which was then modulated by a series
of polarising filters, with one being variable to rotate the
polarisation.
ISTR (38 years ago!!!) that the liquid used was nitro-benzene
OK I follow you now. I had a quick google and found out about nitrobenzene
and modulating polarisation. Never heard of it before. Live and learn.
My original set up was as simple and agricultural as they come, vinyl LP,
scrap motor from a cassette player, Neon attached to am amplifier behind
the 'screen' and a camera made from a lens and an LDR recording onto a
cassette player - the bandwidth was low enough to record on audio.
My latest televisor was made from a circle of black plastic spinning on a
hand fan with a very small torch behind it modulated by the sound from a
small mp3 player. It all folds up and fits in a pocket.


Wow! How many lines and frames / sec?

64 lines of low definition glory, I could not tell you of the frames per
second as I use the same TV as a camera by using the same disk, once the
frame starts are synced it works fine. The syncing is carried out by the
highly technical method of slowing the fan with an index finger.


Andy

"AndyW" wrote in message
...
On 20/02/2014 15:08, gareth wrote:
"AndyW" wrote in message
...
On 20/02/2014 11:51, gareth wrote:
"AndyW" wrote in message
...
On 19/02/2014 09:32, gareth wrote:
LED or nitro-benzine as the polariser?
Polariser?
To my eternal regret, because I disposed of them 38 years ago, I had a
pile of "Amateur Wireless" from the 1930s within which were designs
for mirror-drum scanners, and the modulation was not by a neon light
but with a constant light source which was then modulated by a series
of polarising filters, with one being variable to rotate the
polarisation.
ISTR (38 years ago!!!) that the liquid used was nitro-benzene
OK I follow you now. I had a quick google and found out about
nitrobenzene
and modulating polarisation. Never heard of it before. Live and learn.
My original set up was as simple and agricultural as they come, vinyl
LP,
scrap motor from a cassette player, Neon attached to am amplifier behind
the 'screen' and a camera made from a lens and an LDR recording onto a
cassette player - the bandwidth was low enough to record on audio.
My latest televisor was made from a circle of black plastic spinning on
a
hand fan with a very small torch behind it modulated by the sound from a
small mp3 player. It all folds up and fits in a pocket.


Wow! How many lines and frames / sec?

64 lines of low definition glory, I could not tell you of the frames per
second as I use the same TV as a camera by using the same disk, once the
frame starts are synced it works fine. The syncing is carried out by the
highly technical method of slowing the fan with an index finger.


Picking up on your BW comment, AIUI, the Baird transmssions of 30 line
pictures
were also of the audio BW, and were transmitted as part of the normal
broadcast,
but not at the same time as the audio; it was either speech or video, but
not
simultaneously!

On 24/02/2014 08:12, gareth wrote:

Picking up on your BW comment, AIUI, the Baird transmssions of 30 line
pictures
were also of the audio BW, and were transmitted as part of the normal
broadcast,
but not at the same time as the audio; it was either speech or video, but
not
simultaneously!

I read that.
You would think that it would be trivial to transmit on 2 channels; one
for the video and one for the sound.

The bloke who invented thermal socks should have thought of that.

Andy