Transmitting videos/pictures wirelessly? Need setup help!

[mattofbostone]

Hi ladies and gents,
I was hoping to get some suggestions from you guys/gals regarding wirelessly transmitting pictures or videos at outdoor events.

Heres the background: My school (Clemson) is having a downhill mountain biking race in April. It's going to be really cool and the course is beautiful. One of the things we are trying to do is have a live feed set up on the course that will then be shown at the bottome of the course for spectators. There is one particular jump that will launch these people about 15 feet so it's going to be quite the spectacle.

I was hoping to be able to broadcast a feed from a camera at that jump onto a screen at the finish line. If you guys would be able to help me out that woule be amazing, I havent found much info on the web about it.

Mod- I put this in this section because it is about sports and I thought i would get a better response here however if you feel it should be in the dig. video section I apologize and please move it.

Thanks everyone,
Matt

P.S. We have a few sonsorships that would be willing to cover the expense so thats where the money would come from however it can't be outragesouly expensive or they will just say no HAHA

[SmartWombat]

How far is it from the top to the bottom of the course?
Wireless isn't as reliable as running wires about.
If I had a choice, I'd use wire.

Wireless of a power that you can buy over the counter has a fairly short range.
Up in the trees a fair amount of your signal will be absorbed by the leaves, so unless you use high gain aerials you'll not get the picture down to the bottom.

Using an off-the-shelf 2.4GHz TV transmitter (like the ones in home surveillance) I got a range of about a quarter mile in the open.
That's using the stock 3" bendy twig aerial each end.
You ought to be able to more than double that in the open with beam aerials, and then lose that advantage by having to send the image through the trees.
Water absorbs the 2.4GHz microwave signal (how do you think ovens work?) which is why it gets cut back by the trees and bushes.

Problem with the beam aerials is you have to point them straight at each other, so aiming them is critical to getting the best picture.

I'm not sure about the US band allocations, and the licensing required to do this.
Over here we have the BATC (British Amateur Television Clubs) who publish a technical magazine there must be a similar organisation in the USA.

I found this http://www.hamtv.com/info.html#fccrules which basically says legally you're out of luck - unless you buy expensive licensed systems.

For short distance line of sight non-amateur video link applications up to 1000 feet, we suggest the legal Part 15 FCC Compliant license free wireless video systems offered by Radio Shack (15-2572) and others in the 902-928 MHz and 2.4 gHz bands. A transmitter and receiver system is typically about $100. Only the legal license free devices will all have an FCC ID sticker somewhere on them - any RF device that doesn't, and claims to be license free, probably is not legal. You are free to transmit audio and video for any purpose, business or personal at any time and for as long as you like. The key to getting the best distance is to position the attached antennas to point at each other and to have line of sight between them. The pop up paddle type of antennas often used on the Radio Shack or Wavecom wireless transmitters and receivers are somewhat directional perpendicular to their surface. One just has to move each end around to find the best spot and angle. You cannot legally detach and change the antennas or modify the devices in any way to increase the distance.

There are specific bands above 902 MHz set aside for higher power analog video license free devices in Part 15.249 that allow a maximum of 50,000 microvolts per meter radiated power measured at 3 meters which works out to just under 1 milliwatt to a dipole antenna. Depending on line of sight and antennas supplied, the distance can be up to 1000 feet with good video similar to what you would record on your VCR.


Hope that helped...

[mattofbostone]

Thank you very much smartwombat. That was about as thorough an answer as I possibly could have expected. It sounds like wireless is pretty much out of the picture because the camera would be about 2500 feet from the receiver. Which is also why a wire doesnt seem like a very feasible option.

I do very much appreciate the help and I will make sure to post up the pictures after i get them!