Forum for discussion of narrow-bandwidth mechanical television

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Re: Foxholevision

Postby smeezekitty » Thu Jun 14, 2018 12:02 pm

Unless you are right next to the transmitter, a crystal set doesn't provide nearly enough power to drive an LED/neon. And if you add an amplifier, and no longer a crystal set, it's just a normal radio.
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Re: Foxholevision

Postby Steve Anderson » Fri Jun 15, 2018 3:57 pm

Yes, you do have to remember that the guy in the video mentions he's only one mile away from the transmitter/antenna and doesn't state what its power is. Being the US (I presume) it's probably a lot. In the end he's getting just a few milliwatts of power (I think he mentions 3.5V at 3-4mA, say around 12mW). Not that much for a DC motor let alone the light source and support electronics.

He's also using a 200-foot long wire antenna, not many of us have the space for something like that, say 70m.

A better bet would be a small solar panel and a rechargeable battery - certainly here in Thailand. If you're in the very north of Sweden or Canada perhaps not such a good idea.

We have an AM radio station about two km to the south of us on about 650kHz. It's more of a pain that anything. It's antenna radiates mainly to the north with an ERP (Effective Radiated Power) of 5kW, the actual transmitter is probably 2-3kW. A number of items I have built up have required measures to prevent break-in to the electronics.

As a source of power, it's novel I'll admit, but viable? I doubt it.

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Re: Foxholevision

Postby Harry Dalek » Fri Jun 15, 2018 7:47 pm

It sounds a bit like Tesla's idea he wanted to transmit power around earth free power for all ,lucky for the human race and all animal life he failed ,don't think its healthy living in a microwave oven same go,s for the frequencies he was planning on using . :idea:
Your idea for a passive NBTV receiver is nice you can do it another with a solar cell ,if you have a high brightness white led transmitting NBTV and a solar cell ...connecting the solar cell right to the input of your computers audio input it has the bandwidth ... it will give enough signal to view on Garys NBTV software with out any other electronics so i would think it would light an led hooked up to it a few solar cells might light a bank of leds .
You have the modulating side done ..the moving of the disk is another problem a bank of transmitting leds might also give enough light to drive a small motor via its own solar cells .
For what you want to do never know experiment and find out .
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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Re: Foxholevision

Postby DrZarkov » Thu Jul 12, 2018 11:32 pm

It would be possible to make a "fully mechanicle TV", if you use fiber-optics to transport the light from the transmitter to the receiver, no need for electricity or amplifier at all! Of course it would be too dark to use with a Nipkow-disk, but a small mirror-drum should do the job. Camera and monitor would be the same, you can view the picture through the same lense you will use as camera-lense. The picture will even be in full colour!
The only issue is synchronisation. The clockwork in the receiver would need constant manual adjustment. To me it sounds like an interesting project.
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