Question on how underwater rc control works

[researcher]

Hi everyone. I am a graduate student at the University of Nevada, Reno in Reno, NV. I am currently doing a research project for underwater Virtual Reality. I need to control a phone while underwater and found out that Bluetooth signals don't work well underwater. I was wondering if anyone could help me to understand how normally subs that go into the deep end of the pool are controlled and what kind of gear is used. Thanks!

[subdude]

Bluetooth operates in the 2.4 GHz frequency range, which is far too high to penetrate water. This is why the current Radio Control gear is useless to the submarine world, it also is on 2.4 GHz. To penetrate water, you need a much lower (slower) frequency rate. Most of us in the US use 75 MHz equipment, which used to be the "standard" for ground vehicle operations in the USA. Other countries use 40 MHz, 50 MHz, etc.

In order to use 2.4 GHz, you'll need to trail an antenna to the surface. This can be tricky, as the specs for a 2.4 GHz antenna are quite particular, and require shielded coax for all but the last several inches. Whatever device you use underwater will need to be manufactured to utilize an extended antenna.

Jim

[David F]

A number of us are also now using openLRS on 433 Mhz (458 Mhz here in the UK). Pioneered by Tim on here:

http://subcommittee.com/forum/showthread.php?32640-433mhz-links-and-info-(Tim-s-Regatta-Seminar)&highlight=openLRS

It works well for several feet of (fresh) water on the Goldilocks principle - frequency not TOO high and bandwidth ABLE to cope with frequency hopping and error checking!

David

[tommydeen]

Orrrr find and old 75 mghz set up. I wouldn't wast my time on 2.4 gig it's useless in subs

[researcher]

Wow. Thanks for the great advice! Wireless seems to be very hard to deal with for underwater phone usage. I will probably have to look into waterproof phones, wires, and controllers. It's unfortunate that nobody has made easily accessible alternatives for bluetooth that you just hit a button on a phone and you're live.

[tommydeen]

Wow. Thanks for the great advice! Wireless seems to be very hard to deal with for underwater phone usage. I will probably have to look into waterproof phones, wires, and controllers. It's unfortunate that nobody has made easily accessible alternatives for bluetooth that you just hit a button on a phone and you're live.

Not for blue tooth for reasons stated above by subdude. And since 75 mghz is no longer mfged we in the hobby of subs have taken a big step backwards.... 433 and 915 being the exception.