I tend not to venture out to other forums being in a bit of a rut but I will spread the word of another fun hobby Narrow Band television to those who never heard of it .
First up I live in Melbourne and had always been interested in vintage television very much so mechanical television in all its many forms Nipkows slit drums mirror drum so on and so on many ways to do the same thing ,but I do of late like electronic television projects too.

Since its a bit harder to show my work here I might just link to where I have my projects and what they are and if you like you can view the other pages on the build .

I will start off with classic SSTV .
I made a mechanical sstv drum monitor using glow paint and a laser link below

https://www.taswegian.com/NBTV/forum/viewtopic.php?f=23&t=1318&start=150

i also made a classic P7 version here
https://www.taswegian.com/NBTV/forum/viewforum.php?f=19

https://www.taswegian.com/NBTV/forum/viewtopic.php?f=19&t=2293

Mechanical sstv scanner
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=23&t=1890&start=120

NBTV

mechanical NBTV flying spot camera ..
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=1&t=1523&hilit=camera+question&start=105

PMT mechanical NBTV camera
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=20&t=2139&hilit=pmt+camera&start=60
results
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=20&t=2139&hilit=pmt+camera&start=135

PMT flying spot camera using a scope for the scanning
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=31&t=2412&start=120
results
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=31&t=2467&start=15

Mechanical televsion
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=1&t=1388&hilit=compact+drum&start=45

I had trouble with any thing over 32 line due to vibration plastic to thin below on the second version
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=1&t=1486&hilit=2+drum+monitor&start=90

laser monitor
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=1&t=1557&hilit=octagon&start=15

inductionvisor a proof of concept idea only
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=1&t=2303&hilit=inductionvisor

vidicon
The Cyclops a Vidicon project
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=15&t=2564&start=75

Electronic television

The 3BP1 Anderson monitor
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=17&t=2059&start=480

The Tasmanian Devil VCR139....A for Andrew
32line below
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=31&t=2367&start=75

48 to 64 line
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=31&t=2391&start=15

The Thylacine higher line rate monitor
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=15&t=2436&start=45

Colour perhaps ?
been having problem after problem mainly on th CRT ...magnetic tubes can be a touchy beast ! I have already got raster burn and deflection problems ...some times best to sit back and think retest ,funny enough the circuits were the easy part the CRT and deflection yoke are making me work this time !
Frame Sequential Cathode Ray Tube Project
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=15&t=2586&start=30

Hang on...…..no valves, only those new fangled chip things............….tsk tsk!!!!!!!

Amazing work Harry.
I'll look through all those projects and links.
Fascinating.
Fred.

Hi Fred love all your work too ,,,
But there are sort of valves in my projects CRT's and Photo multiplier tubes .
I do use a lot of the ic and trany things have to admit but I tend to stay away from programmed chips and mini computers I sort of think that
is cheating and can be done a touch more simple with out getting a robot to do the work ,,,not really my thing .
i do like valves just have not used them much ,bit like how the invention of the valve sort of killed the magnetic amplifier .

Opps, I lost the first bit of this post I was mentioning magnetic control systems back in the 1960's and 2 types I encountered in my working life.

1/ static control of load AC power with a DC control signal.
2/ rotary "magnetic amplifier" DC excitors on power Alternators.

1/ The static amplifiers were killed by the advent of the SCR and TRIAC.
I saw AC loads controlled by DC loop signals and watched a team develop a feedback voltage controller with magnetics.
Ultimately this was a failure as the SCR controllers I developed worked so well and were simply PCB assemblies soldered up with electronic parts as opposed to heavy lumps of iron and lots of coil turns. The transformer guys simply did not understand electronics but worse still did not understand the basics of a feedback controlled regulating system and were doomed. I used to look at their experimental work and could see that they had no proper REFERENCE signal and used to suggest to them to make the magnetic equivalent of the Zener diode. Then there systems would have had higher gain and actually worked. I was told to piss off so left them to it. Oddly enough in another device I had exactly what they needed, a toroid core that saturated at low field strength and acted with a sharp knee just like a Zener. You could drive milliamps or amps through a winding and the voltage drop remained constant. The guy running the show could not understand what I was talking about, they were doomed.

2/ The most mysterious of all were the rotating "cross field" DC generator amplifiers that you would see perched on top of a AC alternator.
These utilised the transverse magnetic fields as well as the pole fields and actually worked as the automatic voltage control for the alternators. I remember bringing one back to life by replacing the brushes and cleaning up the commutator. The alternator output was rectified and fed back as a control voltage to a field pole set (the selenium diodes had failed as well and I stuck in silicon diodes). The cross field flux acted as a reference and the control voltage then swung the shunt field flux about the reference field and so controlled the DC output of the armature. (that's my story!). The thing actually gave +/- 1% regulation of the 415 volt alternator output. Most mysterious to the normal electrician as there were opposite brush sets on the commutator that were shorted together to create the cross field and these did not connect to anything else just each other!


All swept away in the 1960's by electronics.
Fred.

HI there Fred
Oh yes magnetic amplifiers been around for a long time I recall the Germans used them in the V2 rockets and high voltage control systems .
Even mini versions were used in magnetic core computers .
The difference as you know is the M A to a valve it needs a AC signal to work much muchness really as the valve needs a heater.

I looked into it my self here mainly looking to controlling a motor speed with a 50Hz magnetic amplifier for a start then looking into higher frequencies.for an electric amplifier as above I wanted a system where I didn't have to use electronics but just electrics that meaning I had to generate the AC via an alternator doable just .below link mainly my early work very much Inspired by Nyle Steiner work .
I very much wanted to stay away from signal generator and use an alternator and my early work on the AC side is here below /

https://www.taswegian.com/NBTV/forum/viewtopic.php?f=8&t=1669&hilit=magnetic+amplifier


Nyle Steiner work is amazing
https://www.youtube.com/watch?v=ci9AI5KuToM

later on I was trying some thing similar on the alternator high frequency idea using stepper motors test bed for VLF transmitter but was never able to modulate the carrier again I just wanted to do it electrically ..have to get back to this one day .
Some video's in this link on the page it still very much interests me reviewing the videos !
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=8&t=2339&hilit=high+frequency+alternator

You have some experience to say the least reading your reply on these beasts I am but an interested hobbyist falling over my feed !