For all you wireless experts out there... I'm talking about the retail
off-the-shelf 2.4GHz video sender-receiver from RadioShack and places
alike. How good are they? Specific questions:

- Do they interfere with household powerlines? What if there's a lot
of them? What about flurencent light?
- How good are they going thru walls? Concrete walls?
- Do they bounce off physical objects? Like people walking thru the
signal path?

I'm thinking of deploying them for a live cast of video cam to a TV in
another room in a building. The distance is not great, probably just
50-70 feet. But the problem is the path way is a z shape corridor so
that non-existence line of sight has to go thru multiple concrete walls
and possible corners....

I'm thinking about using coax using RF modulation if this is not
possible.

Ernest

In article .com,
ernest wrote:

For all you wireless experts out there... I'm talking about the retail
off-the-shelf 2.4GHz video sender-receiver from RadioShack and places
alike. How good are they? Specific questions:

- Do they interfere with household powerlines? What if there's a lot
of them? What about flurencent light?
- How good are they going thru walls? Concrete walls?
- Do they bounce off physical objects? Like people walking thru the
signal path?

The 2.4 GHz signal has a very short wavelength, and tends to bounce
around from various surfaces quite a bit. Multipath interference is a
very real issue. Moving the transmitting or antenna a few inches can
make a big difference in the signal quality.

I'm thinking of deploying them for a live cast of video cam to a TV in
another room in a building. The distance is not great, probably just
50-70 feet. But the problem is the path way is a z shape corridor so
that non-existence line of sight has to go thru multiple concrete walls
and possible corners....

My own experience suggests that you'd be pushing things quite hard
under those circumstances, and would likely not get acceptable signal
quality.

I used one of the off-the-shelf 2.4-gig senders for a year or so, to
retransmit a video signal from a TiVo recorder to a TV in a bedroom
about 30' away. Signal quality was tolerable but not great...
definitely not as clean as a coax could provide. The signal was going
through several sheetrock walls and a cabinet door or two - this was
enough to weaken the signal quite a lot, compares to a straight
line-of-sight path.

If your signal is going to have to go through concrete walls
containing steel rebar, and is going to have to go about twice the
distance I was dealing with, I think you're going to have a terribly
weak signal at the end of the path.

The other problem is one of interference. These devices operate in
the 2.4-gig ISM band, which is becoming extremely crowded these
days... especially with 802.11b/802.11g wireless networks. No matter
which channel you select, you're likely to find that your video image
suffers from visible interference due to 802.11b and some wireless
phones...

.... and the use of any microwave oven, anywhere within hundreds of
feet, will probably wipe out the picture entirely. Microwave ovens
leak a lot of RF, and it's right in this band.

I'm thinking about using coax using RF modulation if this is not
possible.

I think you'll get much better results that way.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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