Transmission of NBTV via liquids

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Transmission of NBTV via liquids

Postby Harry Dalek » Sun Feb 03, 2019 8:11 am

The experiments below are mechanical so i think i have placed them in the correct topic Andrew
To explain what i am up to for a start i wanted to test the best devices i had handy to transmit NBTV via liquid i knew how poor the results were in air and i also knew Transducers well the cheap ones only have a 1 khz bandwidth at 20 or 40khz so they were useless great for SSTV but not NBTV .
Below first 2 photos testing here what ever i had in the way of a mic or speaker side of things that would give me the best results in air they have much wider bandwidth but it seems they are a poor air transmitter or receiver bandwidth wise or both in liquid its another story !
Explaining the reason i am getting multi images below 2 photos i was using big picture version 2 which seems to give that result on a standard video as i was trying to display Baird here , i didn't use the original Big picture as version 2 is less fussy with a poor video signal only reason using v2 here in the air experiment .
IMG_0172.JPG

IMG_0170.JPG


Ok i made a test bath and what ended up being the best for the air transmission was a tiny plastic speaker from a Nokia phone and a 60's reel to reel mic i am not sure what it is in the way or either a dynamic or condenser microphone.
IMG_0178.JPG


Same Baird video this time using the original Big Picture and this time via a Liquid water .
IMG_0176.JPG


Result's as you see are much improved and show the devices do have some bandwidth to them mechanically transmitting the video and receiving it when using a liquid , i would like to see how oil go's trying the bath experiment but water seems fine .
I didn't have a amplifier just using the sound card so various videos gave different results if the sound level was to low also i found some times a direct path was not always the best direction to point the mic in the liquid some times its better to bounce the sound off the plastic bath wall to the mic ...So really i need a little amplifier for the different video sound levels as they are far for being the same .
Its rather interesting effect vibrating the water with your finger causing interference in the video .
Next post i will up load some videos.
IMG_0191.JPG
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Last edited by Harry Dalek on Sun Feb 03, 2019 9:11 am, edited 1 time in total.
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 Harry Dalek » Sun Feb 03, 2019 9:06 am

Here's some videos of my experiment some worked better than others just put them all up to have a look at .
I found this very interesting and sort of touching on liquids and the Jeffree cell idea where as the video is modulated on high frequency sound carrier which would much lower for 32 line NBTV ...its on my mind and you have to start some where with an idea might go no where but this did work .





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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 Steve Anderson » Mon Feb 04, 2019 1:37 pm

Interesting results Harry.

Two things spring to mind here...

1) The speed of sound in water is about 1,470m/s (metres per second), in air it's around 300m/s.

2) The room dimensions are much larger than the container of water.

Reflections from room walls/windows/etc. will have quite a delay, several milliseconds easily. Our ear/brain machine sorts all this out for us, but not NBTV devices. With hard walls and windows the reflections could be of quite a high amplitude, enough to produce the results you are getting. The reflections could be modified by room resonances as well.

The 'water bath' will produce reflections that will be so close in time to the source that they're probably of no issue.

It might be worth repeating the 'air experiment' outdoors in a big open field with no wind - see what you get...

Steve A.

Afterthought...also the frequency response of the transducers (speakers/microphones) will affect the received waveform. As we all know NBTV requires a response down to frequencies that few transducers are capable of.
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Mon Feb 04, 2019 4:40 pm

Steve Anderson wrote:Interesting results Harry.


Hi Steve i was very happy with the results a very simple experiment .

I wanted to test speaker mic or visa versa one or the other could or could not reproduce the sound frequencies of the other .

Research..... Air is a poor transmitter of sound waves !

Tests in Air are dreadful and we are talking Cm from each other to get any result...and you can see a lot of missing bandwidth which both mic and speaker should be able to reproduce better results ..i was thinking may be it's not the devices but the medium between .

i thought lets change the medium to a liquid and see if this helps and we all know its been used in supersonic light valves idea ,just i have not modulated it on a higher carrier for that purpose /

Two things spring to mind here...

1) The speed of sound in water is about 1,470m/s (metres per second), in air it's around 300m/s.

2) The room dimensions are much larger than the container of water.


Do different frequencies travel in a liquid or air at different speeds ?
looking it up !
As a result, sound waves travel faster in solids than in liquids, and faster in liquids than in gasses. While the density of a medium also affects the speed of sound, the elastic properties have a greater influence on the wave speed. The density of a medium is the second factor that affects the speed of sound.


With the air and water tests i would of guessed that low frequencies would do better seems the case for whales chatting to each other sonar and such but why to the higher frequencies work ,there's a bandwidth increase when using liquids and the higher frequencies .
Dolphins have the ability through echolocation to emit sounds with a frequency of 120 kHz ! so that works well in water for them to find fish with ultra sound.

I was just reading that the U S navy can produce sonar with transducers up to 1 ghz !

Sound waves induced in water, with frequencies ranging from 100Hz up to a 1 GHz.

The higher the frequency, the smaller the features that can be detected, but also the smaller the range of detection becomes. Very low frequencies are difficult to induce in water, they would require humongous “loudspeakers”.

So to detect a submarine at a distance of 10 km you’d use rather low frequencies with wavelengths (in water) of shorter than 10 meter / frequencies of 150Hz to a few Khz.



Reflections from room walls/windows/etc. will have quite a delay, several milliseconds easily. Our ear/brain machine sorts all this out for us, but not NBTV devices. With hard walls and windows the reflections could be of quite a high amplitude, enough to produce the results you are getting. The reflections could be modified by room resonances as well.

The 'water bath' will produce reflections that will be so close in time to the source that they're probably of no issue.

It might be worth repeating the 'air experiment' outdoors in a big open field with no wind - see what you get...


The problem with Air test for NBTV the devices have to be very close to 1cm or they don't work at all even to the point you would think cheating with induction of the coils in the speaker to mic that close would help but still don't help ! results are dreadful in air .
Factors like volume don't seem to help either
IN the bath liquid test direction and reflection off the walls from the speak to mic they ... don't have to be close , there are sweat spots where direction of the sound in the liquid becomes strongest when i have time i with try it in a bigger bath but distance wise its better than air as well /
So what i think its showing is the speaker and mic can produce transmit and receive at least a bandwidth frequencies enough to produce the NBTV video ..Looking at the air result what you think the bandwidth was for that result ?
I would think 1 khz to 3 at best replacing the Air medium with water the bandwidth transmit to receive is increased guessing 10khz or over ? ...i know to find out i need to do a sweep test up to 20 khz

Steve A.

Afterthought...also the frequency response of the transducers (speakers/microphones) will affect the received waveform. As we all know NBTV requires a response down to frequencies that few transducers are capable of.


My thoughts here are the speaker as a transmitter i used it must be just due to its size giving better results on the higher frequencies what we know to get a range in loud speakers is to use a woofer and tweeter ...trouble here is a speaker say even twice the size are no longer made from plastic but paper not good for the experiments in water !

I wanted to see once i get my hands on enough oil to give that a go ...
In the Scophony system supersonic light valve used paraffin oil in its light valve again a bit off what i am doing here but in that case it was the modulated supersonic sound waves were changing the density on the liquid changing the liquids transparency to light .

But water has a higher density than oil so results should be different in a transmitting test ....my guess now with studying this is the results would be worse .
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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 Steve Anderson » Mon Feb 04, 2019 5:05 pm

Hi Harry,

Well, it seems you've looked into this well, I can't really offer any further suggestions.

As interesting as this is, why are you doing this? I can't see much application for it, except plain curiosity - unless I've missed something - which is very possible!

Steve A.
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Mon Feb 04, 2019 6:13 pm

Steve Anderson wrote:Hi Harry,

Well, it seems you've looked into this well, I can't really offer any further suggestions.

As interesting as this is, why are you doing this? I can't see much application for it, except plain curiosity - unless I've missed something - which is very possible!

Steve A.


Yes Curiosity ,,do you remember the saying why is it so from the very scary ! Julius Sumner Miller well as someone under 10 watching him i did learn to ask the question and see if i can come up with the correct answer !
I am doing this because i didn't know why it didn't work in air and what is a replacement for a pricey wide bandwidth ultra sound transducer ....it sort of also is around subject of the jeffery+cell which interests me if there's another way to do it ....i don't want to say i am going to make one but its a subject on my mind how to make a lower bandwidth version of it ....since NBTV so low i don't think i need to use a carrier crystal ..
with just a speaker to compress a liquid such as paraffin oil would you get the same result NBTV its much slower narrower ....you could use a wide bandwidth transducer and modulate it but i don't think i need it ...
If i can transmit video via paraffin oil as in the water experiment if that works next step would be make a cell where the crystal is replaced with a tiny speaker ...Just for the hell of it Steve.
The water transmitting is a first one of those things what next ....
BTW would be interesting to transmit video across a pond lake if i were more adventurous


youtu.be/RUgJUcJ2Xxc
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Re: Transmission of NBTV via liquids

Postby Andrew Davie » Mon Feb 04, 2019 7:26 pm

I also thought he was very scary!!
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Mon Feb 04, 2019 11:12 pm

Andrew Davie wrote:I also thought he was very scary!!


Yes those poor kids that had to think and come up with an answer to he's Questions ...that's what happens when you go to a private school they are expected to know the answer !

I am not sure if video has been ever transmitted via a liquid apart from in light valves,i thinking of a practical use could be used to send data as well as video might be of use to navy's more than likely already do this and we don't know about it who knows ....any case liquid video modulation exists now if it didn't before. .
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 Harry Dalek » Tue Feb 05, 2019 4:41 pm

I have tried some thing i had handy today and that was Methylated spirits just to see Methylated spirits is predominantly ethanol, which has a density of 0.785 .. any case it was as i expected its less dense than water so the result was very poor...just shapes at best
looks like water but sure isn't !
IMG_0221.JPG


Multi Baird heads below but result very poor with this liquid water is much more dense and better for this .
IMG_0220.JPG


So i can't see any thing else working unless its density is close or over the density of water ...so looking into it Glycerine Density is 1259 water is about 1000
that might be some thing to try it would be better than water ...it was a chemical mentioned that can be used in the ultrasonic cell page i posted up.... be interesting to try .
glycerol, glycerin or glycerine. All 3 names refer to the same compound and seems easy to get .

Liquid Paraffin is about 880 and close to benzene glycerine seems a safer chemical to these
Density chart
https://www.engineeringtoolbox.com/liqu ... d_743.html
Last edited by Harry Dalek on Tue Feb 05, 2019 11:46 pm, edited 1 time in total.
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 Andrew Davie » Tue Feb 05, 2019 7:20 pm

Harry Dalek wrote:I am not sure if video has been ever transmitted via a liquid apart from in light valves,i thinking of a practical use could be used to send data as well as video might be of use to navy's more than likely already do this and we don't know about it who knows ....any case liquid video modulation exists now if it didn't before. .



Everybody wants to watch TV in the bath. Now they can!
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Re: Transmission of NBTV via liquids

Postby gary » Tue Feb 05, 2019 8:53 pm

Maybe I am stating the obvious, but the purpose of the Jeffree Cell (and similar) was NOT to propagate a signal through a medium but to modulate a signal through that medium, in other words it was a light amplifier whereby a very constant bright light was modulated by a very low energy signal. A light transistor so to speak.
Perfecting an NBTV system is like trying to slam a revolving door...
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Re: Transmission of NBTV via liquids

Postby Harry Dalek » Tue Feb 05, 2019 11:40 pm

gary wrote:Maybe I am stating the obvious, but the purpose of the Jeffree Cell (and similar) was NOT to propagate a signal through a medium but to modulate a signal through that medium, in other words it was a light amplifier whereby a very constant bright light was modulated by a very low energy signal. A light transistor so to speak.


Yes Andrew transmit TV via your toes bounce a test card off your bottom :shock: !

HI Gary one thing leads to another sometimes a road to no where ! been there many times but sometimes one road leads to another road .
And i am just thinking about it in the thoughts below and i will do a test at a time and see if it go's any where ?.
I didn't start out to do any thing with liquids just ended up a answer to the Question on why transducers with the bandwidth work poorly in air .
Transmitting NBTV via a liquid with the correct density ( lucky water is or i would not of bothered) ....but ended up the answer to the first question i found that interesting .
Yes not a jeffree cell here ............ i understand that but a jeffree cells liquid needs 2 things to be the correct density and the correct chemical properties where as in it has to be able to transfer the bandwidth and change the transparency or is it polarization of light passing the via the cell .. with the compression of the Am modulated signal .
Doing what i was up to got my mind ticking thinking of the jeffree cell .........not in its original form but a sort of likeness low bandwidth version.
Transmitting NBTV via a liquid with the correct density is proof only of the density of the liquid needed.
Proof on concept on the density of the liquid would be replacing the water with some thing of the same density and doing the same transmit test .
That's what i was thinking about a step by step process to test that part of the idea .
Compression of the light valve liquid and giving a change in transparency to light i have not seen apart from an article i have onit ,it seems a fairly simple device ,in its original form perhaps not with the the crystal in the 10 MHZ range needed due to the bandwidth of the high line rate video ...here for nbtv any way the transducer can compress the liquid NBTV is Am wouldn't it do the same thing ? ...not a jeffree cell as but same sort of idea ...a clear tube inside cork to stop dampen reflections one end of the tube then filled with glycerine and a trpolarization of light ansducer other end ...
I have other articles on the jeffree cell...i will post up when i have time ...always easy to speculate not so easy to make something work but fun to think about it ..
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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 Harry Dalek » Wed Feb 06, 2019 2:43 pm

Good topic to go on with
Something that came to mind on normal ultrasonic transducers is the low bandwidth is this the device or in the medium of air ?
I was playing around with ultrasonic's before i began testing the best speaker mic and looked into that ,i was working out a way to Am modulate the transducer it ended up working in another passive modulation way with a transformer works well .
Any case i will look into that if the bandwidth of the device is increased via a denser medium .

Back on to the Jeffree Cell...The ultrasonic one is interesting from the 50s i missed the bit on the short range communication test they did ...the whole thing is a must to read if you are interested in this .
The xylene is mentioned ,i used to make that at BHP also..... its another light oil it was mixed in the benzene we made ..Toxic of cause funny enough easy to buy !
Below is what i found in electronics oct 1941
Electronics-1941-10-048.jpg

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Electronics-1941-10-051.jpg

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Next Radio and electronics 1949
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Radio-Electronics-1949-03-037.jpg

Radio-Electronics-1949-03-038.jpg


Electronics 1951
Electronics-1951-03-090.jpg

Electronics-1951-03-091.jpg

Electronics-1951-03-092.jpg

Electronics-1951-03-093.jpg

Electronics-1951-03-094.jpg


Electronics 1939
Electronics-1939-10-OCR-Page-0044-1.jpg


Television and shortwave world 1937
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....................................
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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 Harry Dalek » Thu Feb 07, 2019 7:56 pm

I tried a frequency sweep best is here a bath of salty water....
IMG_0249.JPG




I also did buy some Glycerine....funny enough one is for cooking other for skin care ! difference ?
IMG_0231.JPG

IMG_0235.JPG

its thick a but a bit thinner than honey transmitting not as clear as with water or salt water in the jar not easy to test .. i then swapped to a bath so i could adjust mic direction as in video below

Transducers distance is reduced when using Glycerine water is better and salt water id say the winner so far .
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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 » Fri Feb 22, 2019 7:25 am

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.
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