Transmission of NBTV via liquids
Posted: 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 .
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.
Same Baird video this time using the original Big Picture and this time via a Liquid water .
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.
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 .
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.
Same Baird video this time using the original Big Picture and this time via a Liquid water .
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.