Hi!
I have to communicate through water using RF. I would apprecciate any help or suggestions.
Thanks
Elias
what range do you need? What power and size restrictions do you have?echav:
Hi!I have to communicate through water using RF. I would apprecciate any help or suggestions.
Thanks
Elias
My understanding of the matter is that if you want any sort of range you need to operate in the VLF (Very Low Frequency) range. Higher frequencies are unable to penetrate very far into water.
Water penetration depends on a lot of things. the RC submariners get several feet of penetration with their 27-72MHz radios in pool and fresh water. Salt water is like trying to stare through a brick wall, though, if you try anything above several kilohertz. That frequency range, obviously, is a very power hungry and inefficient application :). Lower the frequency the better, but you also cut into your data rates and may end up running over someone else’s spectrum. Best best is to try 27MHz if you can find/build a transciever pairing that will suit your needs. 434MHz and 900MHz may penetrate a bit, 2.4GHz and higher probably not at all.
How about ultrasound? It works a lot better in water, or so I hear. I think you’d still have trouble getting more than a thousand or so bits per second though, just based on the specs I see on ultrasonic transducers.