Transmission of NBTV via liquids

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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Mon Feb 25, 2019 6:13 pm

Klaas Robers wrote:You might realize that television signals are transmitted and received through glass. It is in the glass delay line in PAL and SECAM colour televisions. Althouhg it is not the total signal, it is the colour subcarrier signal, and the delay is 64 us, one TV line. It works on 4,4 MHz and the bandwidth is still about 1 or 2 MHz. You can surely modulate an NBTV video signal onto a 4,4 MHz carrier, send that through the glass delay line and receive it at the other transducer.

As the bandwidth of the quartz transducers is rather limited, you cannot send a baseband video signal through the line, only something centered around the resonance frequency of the crystal.

In the very very beginning of PAL-TV Telefunken used a stretched delay line. One crystal transducer at one end, the other at the other end. The problem was: how to tune the proper delay time? thus a folded line was made, half the length, where the signal reflected against the far end. Both transducers were situated side by side at the same beginning end. By grinding the far end, while measuring the delay time, the tuning was much easier.

Later the super-folded lines were made, where the accoustic wave reflected against side walls and the end wall. By grinding one wall the tuning is performed. Harry, you opened such a line.


MMMM interesting Klaas .
I was about to reply to your last post on the delay lines ...noticed you had posted here
When i was reading up on sound waves sold objects it seems are better than liquid in transmitting sound waves gases the worst ....i suppose the old can with a string and a can at the other end is a way of transmitting voice bandwidth same idea with transducers speakers mic you would think would work as well for say NBTV ..
I will keep that idea in Mind Klass about the delay lines i found a few in my junk box ,all look similar with connections on the edge of them and reflection bumps on the flat glass one side.
The tub i used for these liquid tests would be a delay line too as you mentioned at the end of your message ....length longer or bouncing off more walls more delay .
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: Transmission of NBTV via liquids

Postby Klaas Robers » Sat Mar 02, 2019 8:38 pm

Because the crystal is damped by the glass, it is difficult to use it as an oscillator. Try to make a 4,4MHz signal with another, normal crystal, modulate that and apply it to one of the two delayline crystals. Then with the oscilloscope you can see it coming from the other crystal, delayed by 64 us.
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Sat Mar 02, 2019 9:50 pm

Klaas Robers wrote:Because the crystal is damped by the glass, it is difficult to use it as an oscillator. Try to make a 4,4MHz signal with another, normal crystal, modulate that and apply it to one of the two delayline crystals. Then with the oscilloscope you can see it coming from the other crystal, delayed by 64 us.


Hi Klaas
i never mentioned it yet but that is some thing i tried yesterday with the Jeffree cell valve Hartley oscillator and on the dual scope i could see the delay from the input to out ,yes i think you could transmit via the delay line if you modulate in on the 4 mhz crystal .
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: Transmission of NBTV via liquids

Postby Klaas Robers » Mon Mar 04, 2019 4:28 am

Modulate onto 4.4 MHz, that is the center frequency of the PAL delay-line. And if that works, you have transmitted an NBTV-signal via glass. You may consider glass to be a under cooled liquid, because it is amorphous, just like all liquids.
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Mon Mar 04, 2019 8:14 pm

Klaas Robers wrote:Modulate onto 4.4 MHz, that is the center frequency of the PAL delay-line. And if that works, you have transmitted an NBTV-signal via glass. You may consider glass to be a under cooled liquid, because it is amorphous, just like all liquids.


It was interesting i was changing the frequency its very tight but the delay line does have a little play ,i should of had the frequency meter checking this .
But as you change the frequency you can change the delay out which must be different to want is expected on 4.433...but you can never line the input to the output sine wave it just jumps out of phase to the other side when you try changing frequency and line it up .
Transmitting in this solid delay line would be possible is interesting to hear from you ..Am modulating it i will have a think about it ..can't be any harder than than the AM modulating the 40 khz ultra sonic transducer narrow band idea i was working on before the liquid NBTV experiments .
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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