Lower-frequency video transmission? - Tricky ...

[bradv]

Hi All,

Just wondering if anyone has any experience with transmitting wireless video from underwater at 900MHz? This frequency is substantially lower than the common 2.4GHz video transmitters available which won't work u/w, but I'm hoping that as R/F attenuation through water decreases with frequency, reception at 900MHz may be possible with a relatively-powerful signal (800mW).

Any thoughts? Yes, I realize that this aim is difficult to achieve. Even a few feet would be nice

[wadester13]

I am building my sub

I am building my sub from the real thing. I was on a sub for 4 1/2 years. The video is mainly to look at stuff above the water line. It may be neat to see under water but if you run in a pond you wont see anything. I may be wrong on this. If you want to 'see' under the water try working on prefecting sonar!

[bradv]

As my sub is a

As my sub is a Dumas Akula and thus relatively small (88cm), it'll mainly be run in pools and at a shallow depth in lakes - littoral combat So I should get good video visibility in these situations - I just need to make sure the 900MHz video signal can punch its way back out of the water.

[Guest]

Brad,
If you're only running at

Brad,
If you're only running at shallow depths, why not put the camera in the sail, with a tall antenna which will be above the water? I have a 1.2Gh CCTV in the sail of my L.A. I can read an uderwater sign on the end of my 40ft pool on my video monitor. In the lakes, visibility is only a few feet, because of the lack of water clarity. See picture on my SC homepage, and videos on my web site]Art Broder's Models[/url]. Go to Documents, and view videos. You may have to join the group, (free) to see the videos.
Art

[scott t]

How about designing a retractable

How about designing a retractable float antenna for when video is wanted?

[ramius-ii]

Hi Brad]http://www.subcommittee.com/forum/icon_smile.gif

Hi Brad]http://www.subcommittee.com/forum/icon_smile.gif[/img]

[interpol]

Make sure that you are

Make sure that you are licensed to operate whichever frequency you choose. If you are in the US, in the 1.2Ghz range I do believe that you need an Amateur Radio Operator's license, and your output power, since it is a remote controlled vehicle, will probably fall under the category to be limited to 1 watt.