Antenna for GSM/Wifi


#1

Hi guys, I'm planning on building an Android based ROV similar to OpenROV, and putting an android phone as the brain (with its camera and connectivity)

I was wondering, has anyone tried connecting an antenna cable from the ROV up above the water? wondering if I could pull of GSM this way, and use that as my communication channel.


#2

For any decent length of cable you are going to need a pre-amp at the floating antenna, which will make the cable one-way. Somehow you need to get a signal out of the camera to tell the pre-amp if you are sending or receiving. I know RF but I don't know enough about Android phones to know how hard that will be.


#3

Well, I'm not very good with RF so it was just an idea since I know from experience that holding a wire next to the phone tends to improve reception.

since the sub is a small hobby project, I would not need it to work for more then 2-3 meters.

will I still need a preamp?


#4

For 2-3 meters it is worth a try without a per-amp. Get the lowest loss cable you can. Unless you have a better idea I would make a simple dipole antenna on the phone end and a 1/4 wave ground plane in the surface float. Both these types of antennas are very simple to construct.

http://en.wikipedia.org/wiki/Dipole_antenna

http://www.vias.org/wirelessnetw/img/wndw-print_img_44.jpg - example of 1/4 wave ground plane.


#5

Wow, I really know nothing about electronics.

but I'll look at the links you sent me, maybe I'll learn something.

Thanks!