Take a look at these wireless video senders/receivers:

http://www.avdeals.com/transmitters.htm

I need a bit of product research done on these, so that these
questions can be answered:

1) What is the difference in the 2.4 ghz and 5.8 ghz versions (besides
the frequencies)? Why use one over the other? What can I expect if I
use the 5.8 ghz version?

2) Will the 5.8 ghz version conflict with existing wireless devices?
If so, which ones? I already know that 2.4 ghz frequency spectrum is
used by many devices, including cell phones and wireless Internet, but
I'm sure about 5.8 ghz.

3) Where can I buy a *very* long range (500 - 800 ft) version of the
5.8 ghz wireless sender/receiver. I need something which will pass
through walls easily, too. The 300 -400 ft version are not long enough
range for what I want to do. I'm looking for a reputable store with a
good track record of customer service, preferably in the USA.

thanks!

1)  Generally whenever you see a higher frequency for any type of
device, that means the consumer product manufacturer can use less
power to transmit the same distance. Or if the same amount of power is
used, greater distance. Higher frequencies are usually "less busy"
(less interference with other stuff at home) than lower ones, because
the transciever manufacturers don't all jump at once onto higher
frequency parts because of the higher costs on all ends. They prefer
to wait until demand hits critical mass. Perfect example of this is
wireless phones: 2.4GHz models were out for several years, then 5.8GHz
was approved by the FCC, and manufacturers moved to 5.8 one at a time,
very slowly. Why? Because the 2.4's can be manufacturered and sold
cheaper. The only difference between 2.4 and 5.8, in the case of
phones, is probably a single chip from the radio chip manufacturer. Or
to answer more simply: Business 101 supply & demand.

2) 5.8GHz will conflict, but today less than 2.4GHz. Because 2.4 has
been around so much longer, there are simply more devices that can
conflict. You probably have a few years of 5.8 being "less crowded"
than 2.4, but then 5.8 will be just a difficult. And then of course
the next higher frequency will be available and the story will go on.

3)  The distances given by any manufacturer is the absolute best case
distance in absolute perfect situations (no walls, no other
interfering devices, probably perfect weather to boot - most likely
tested either outside or in a huge open empty wooden warehouse). Move
your device into a typical house and you'll get a 50 to 95% reduction
in distance, depending on every wall the signal has to go through,
every piece of metal along the way, whether your microwave oven is in
use, and many other factors. So this means to achieve long distance
indoors, you will have to go to a higher class of devices - which are
more expensive than the $99 2.4GHz types you see everywhere.

Just Googled and found a possible suppliers of higher end products:

http://www.wirelessvideocameras.com/cgi-local/SoftCart.exe/online-store/scstore/shophome.html?E+scstore

http://www.nvsystems.com/wireless.htm

Here's the Google: ://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=%22wireless+video%22+%225.8+ghz%22+%22long+range%22

Good luck.