'Radio'control submarines...

Thread Starter

Externet

Joined Nov 29, 2005
2,201
Hi.
How are the submarines commanded ? Is it <100KHz or ultrasonics ? What if you want wireless video return ? Is there any first-person-view FPV submarine ?
 

ArakelTheDragon

Joined Nov 18, 2016
1,362
You can not emit or pass radio waves through water, receive or transmit. You need a periscope which is an antenna that works on a certain depth, but no more.
 

ArakelTheDragon

Joined Nov 18, 2016
1,362
The submarine has a built in periscope that works on a certain depth. They are tricking you with this. The most accurate statement is "you need a periscope which works on a certain depth". You can not call it "no periscope".

I don't offend both of you, I appreciate that you don't offend me either.
 

Alec_t

Joined Sep 17, 2013
14,280
The lower the frequency the longer the wavelength and hence the bigger the antenna needed for a given signal strength. Antenna size becomes unmanageably large for anything other than short range transmission in water.
 

AlbertHall

Joined Jun 4, 2014
12,345
How will the signal be received or transmitted? is the table you give without an antenna(periscope=antenna)?
Transmitted and received by standard model control equipment, with the antenna on or in the model.
With say 27MHz you can't go very deep but you really don't want to - if you can't see it you can't control it.
 

Thread Starter

Externet

Joined Nov 29, 2005
2,201
The wavelength of radio frequencies is different in water than it is in air. Uses much, much shorter antennas.
Water is a very lossy medium, but not a impassable medium. Never had a submarine 'radio'control, that is why am asking how they do it, if they do it.

upload_2019-1-31_15-37-12.png

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Telemetry modem:
upload_2019-1-31_15-49-24.png
 

ArakelTheDragon

Joined Nov 18, 2016
1,362
They don't do it. You are describing exactly the same a periscope on a certain depth, thats why in movies they say go to periscope depth. This is just a trick saying "no periscope".
 

Thread Starter

Externet

Joined Nov 29, 2005
2,201
For proper Tx/Rx antennas submerged, without the extra loss of air-to-water-to-air refractive boundary loss, range is better. This is not about dipping in water a vulgar collapsible rod antenna.

Another way is optical. Blue led arrays/photodiodes. Perhaps that is what they use, if they do it ?
 
Last edited:

WBahn

Joined Mar 31, 2012
29,978
You can not emit or pass radio waves through water, receive or transmit. You need a periscope which is an antenna that works on a certain depth, but no more.
Simply, factually not true.

Read up on ELF communications which are capable of communicating (one-way) with submarines at their operating depths with no antenna periscope or buoy. ELF waves can penetrate several hundred meters into the ocean and, in air, have negligible attenuation making it so that a single transmitter can communicated with submerged submarines anywhere in the world with only about 8 W of radiated power. The down side is that it takes a few megawatts of input power to achieve that.
 

oz93666

Joined Sep 7, 2010
739
Submarines offer great possibilities because they can be relatively small and support great weight ...

Why bother with RC ? You could easily build one big enough to get in yourself.
 
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