Lots of great info so far, krackula and Steve--thanks! One question: what
do you mean by "soft video"?

"Steve Uhrig" wrote in message
...
... SNIP ...
This will give you soft video.

NP ....... I had a friend that owned an auto parts yard. he had 8
channels of professional , high powered, wireless 2.4 gig installed.
he had it for only about 4 months and a lady down the road , a
quarter of a mile, got a new ( $79 ) digital cordless phone for
christmas and completely ruined the system. made his entire
investment nearly useless. ( anytime her phone is plugged
into the wall and not being used , it sends out a channel scanning
signal that hops over a set of 50 different channels which acts as
beacon for the handsets to help them know which channels are clear
and ready to be used by the system . with-in these 50 channels are
the same channels ALL 2.4 gig cameras use too . when this signal
sweeps the video camera channels it causes the picture to destabilize
momentarily and makes a loud " psssst " in the audio channels,
every 3 or 4 seconds )
he offered to buy her a new 5 gig cordless phone with two
cordless remotes if she would surrender her 2.4 gig model.
she declined saying the 2.4 was a gift from her children
and wouldn't part with it. he had numerous other interference
problems , tho, and local teenagers started playing hide
and seek games in his lots ( full of cars ) using those
hand held video monitors ( like the icom ic-r3 ) and paintball
guns. he could never catch them, because they always knew
when he was coming ...... ha hahah h haha . ( parts thiefs would
have had the same advantage )


k..........


On Thu, 18 Mar 2004 13:28:10 GMT, "DougSlug"
wrote:

Lots of great info so far, krackula and Steve--thanks! One question: what
do you mean by "soft video"?

"Steve Uhrig" wrote in message
.. .
... SNIP ...
This will give you soft video.

On Thu, 18 Mar 2004 16:09:58 GMT, krackula wrote:

NP ....... I had a friend that owned an auto parts yard. he had 8
channels of professional , high powered, wireless 2.4 gig installed.
he had it for only about 4 months and a lady down the road , a
quarter of a mile, got a new ( $79 ) digital cordless phone for
christmas and completely ruined the system

Then the system was not professionally designed and installed.

Very VERY few are. There's a lot more to this stuff than buying black
boxes from a spy shop or dealer and hooking them up.

There isn't enough space in the 2.4 ISM band to support 8 channels of
video. 5 is the maximum, even with gain antennas to isolate. If there
were 8 channels, they were spaced too closely, the receiver AFCs were
fighting to decide between several channels and the effective
sensitivity of the receiver would be reduced significantly.

I will acknowledge you can get more separation by going to circularly
polarized antennas instead of linear, and making each adjacent
frequency the opposite polarization, but you're talking a lot more
engineering than nearly anyone would be capable of. Anyone putting in
a system in an auto parts yard is not going to be doing military grade
work and spending a few hundred dollars each for sixteen antennas.

The ready availability of wireless stuff has made every wannabee into
a video and surveillance expert. If you don't believe they're an
expert, ask them. They all think they are. The appropriate test
equipment alone costs more than most of these companies will earn in a
year.

I train government law enforcement and see what it takes to bring
competent experienced professionals up to speed on wireless video.
It's nearly impossible to find a website or catalog with honest specs.
250 milliwatts at 2.4 is insanely high power and virtually never
needed. All the work in wireless video is done in the antennas, not
with raw insane transmit power.

I've personally examined several alleged high power transmitters and
not one was anywhere near rated spec. Jumping out the attenuator pads
in the Wavecoms more often reduces ERP than increases it, because
people screw up the impedance jumpering. You have to jumper with
copper strap, not wire, and maintain the precise inductance as the SMD
resistors you're replacing, or you lose signal instead of gaining it.
Very easy to see on a spectrum analyzer.

local teenagers started playing hide
and seek games in his lots ( full of cars ) using those
hand held video monitors ( like the icom ic-r3 ) and paintball
guns. he could never catch them, because they always knew
when he was coming

Another indication the system was not professionally installed, if
true.

I owned an R3. Others have brought theirs over here too.

My home and shop are next door to each other, on adjacent properties.
I test between buildings. I keep a Part 15 2.4 gig video transmitter
running constantly with color bars modulating at the house, as a test
source for receiver work at the shop. Antenna is a rubber duck about
the size of a cigarette.

Proper equipment with simple rubber duck antennas makes it fine
between the buildings, which are wood frame and only a few hundred
feet apart. No foil backed insulation, just paper.

The R3 would not see the same transmitter through one adjacent wall in
the next room, maybe fifteen feet airline. The professional receiver
sees full quieting even in the pouring rain when you need a
significant fade margin.

Anyone expecting the R3 to receive wireless video is likely to be
disappointed.

Steve


************************************************** *******************
Steve Uhrig, SWS Security, Maryland (USA)
Mfrs of electronic surveillance equip
website http://www.swssec.com
tel +1+410-879-4035, fax +1+410-836-1190
"In God we trust, all others we monitor"
************************************************** *******************

The R3 would not see the same transmitter through one adjacent wall in
the next room, maybe fifteen feet airline. The professional receiver
sees full quieting even in the pouring rain when you need a
significant fade margin.

I'm not any expert, but that has been my experience, also. After failing to
pick up any 2.4 GHZ video on my R3, I gave in and bought a wavecom
tramsmitter/reciever pair.

I transmitted from my bedroom, which was a very small room at the time. The r3
picked it up inside the room, but could not pick it up at all outside the
bedroom (only about 3 feet away), while the Wavecom reciever picked up the same
transmission from several rooms away.


Anyone expecting the R3 to receive wireless video is likely to be
disappointed

And yes, I did expect the R3 to recieve wireless video (from all of the
advertising hype about it), and yes, I was sisappointed with it as such.

As I said, I'm not any expert on this stuff.

So it's good to have experts like you in this newsgroup. so that I and others
csn learrn about some of this stuff.

On Thu, 18 Mar 2004 13:28:10 GMT, "DougSlug"
wrote:

Lots of great info so far, krackula and Steve--thanks! One question: what
do you mean by "soft video"?

The receiver doesn't have the bandwidth for the extremely wide
(relatively speaking) video signal of several megacycles. At a minimum
you'd have to come off the I.F. and I still doubt you'd see decent
performance.

I don't know the receiver, but it needs to demodulate FM video to work
at all.

The various ICOM receivers with accessory video adapters stink, but
without something better to compare them to you wouldn't know.

'Soft' means loss of the high frequency component at the band edges,
which is contrast and sharp details. Take your TV, turn the control
down from sharp to soft, and drop the contrast way back and you'll
see. Colors, if you use color, will not be as crisp.

If you use a decent high gain/very directional antenna on the receive
end, you'll have a huge amount of fade margin and due to FM capture
effect you are very unlikely to see interference from any Wi-Fi or
cordless phone unless someone happened to be using the other device in
the path (unlikely) and close enough to the receive antenna (also
unlikely).

Using the standard FCC Part 15 transmitter with very low TX power and
making more system gain on the receive end where it's cheaper and
legal, will go a long ways towards others intercepting the signal.
It's not nearly as easy as the media likes to claim, or persons who
haven't really done it. If someone is within maybe 150 feet with an
average receiver they may get lucky. Anyone trying to intercept with
purpose-built equipment could do better, but I rather doubt that's a
concern.

I've done just what I described a zillion times all over the world and
had essentially no problems. I shot across the entire city of Seoul,
over 20 miles airline from high rise rooftop on the receive end with a
dish to a covert transmitter with patch antenna in another building
with a facing window. Other than having some difficulty aligning the
razor sharp patterned receive antenna with a compass and map it worked
perfectly. You won't have an alignment problem because you can see the
other end.

The directional antenna (acceptable for use on receive end only) gives
you a much stronger pattern in the direction in which it is pointing,
and tends to reject signals from above and below, sides and rear.
Depending on the size/gain of the antenna, your pattern might be 60
degrees down to 10 degrees or so. The more the better. Antennas at 2.4
are relatively small and lightweight and little wind loading.

Read the antenna article in the White Papers section of our website
for more info on antennas, gain, and why it matters.

Steve


************************************************** *******************
Steve Uhrig, SWS Security, Maryland (USA)
Mfrs of electronic surveillance equip
website http://www.swssec.com
tel +1+410-879-4035, fax +1+410-836-1190
"In God we trust, all others we monitor"
************************************************** *******************

Can you connect the discriminator o/p of the aor ar 8200mk3 to the video in
of a scart cable and tune around 2.4G??

Xanax.
"Steve Uhrig" wrote in message
...
On Thu, 18 Mar 2004 13:28:10 GMT, "DougSlug"
wrote:

Lots of great info so far, krackula and Steve--thanks! One question: what
do you mean by "soft video"?

The receiver doesn't have the bandwidth for the extremely wide
(relatively speaking) video signal of several megacycles. At a minimum
you'd have to come off the I.F. and I still doubt you'd see decent
performance.

I don't know the receiver, but it needs to demodulate FM video to work
at all.

The various ICOM receivers with accessory video adapters stink, but
without something better to compare them to you wouldn't know.

'Soft' means loss of the high frequency component at the band edges,
which is contrast and sharp details. Take your TV, turn the control
down from sharp to soft, and drop the contrast way back and you'll
see. Colors, if you use color, will not be as crisp.

If you use a decent high gain/very directional antenna on the receive
end, you'll have a huge amount of fade margin and due to FM capture
effect you are very unlikely to see interference from any Wi-Fi or
cordless phone unless someone happened to be using the other device in
the path (unlikely) and close enough to the receive antenna (also
unlikely).

Using the standard FCC Part 15 transmitter with very low TX power and
making more system gain on the receive end where it's cheaper and
legal, will go a long ways towards others intercepting the signal.
It's not nearly as easy as the media likes to claim, or persons who
haven't really done it. If someone is within maybe 150 feet with an
average receiver they may get lucky. Anyone trying to intercept with
purpose-built equipment could do better, but I rather doubt that's a
concern.

I've done just what I described a zillion times all over the world and
had essentially no problems. I shot across the entire city of Seoul,
over 20 miles airline from high rise rooftop on the receive end with a
dish to a covert transmitter with patch antenna in another building
with a facing window. Other than having some difficulty aligning the
razor sharp patterned receive antenna with a compass and map it worked
perfectly. You won't have an alignment problem because you can see the
other end.

The directional antenna (acceptable for use on receive end only) gives
you a much stronger pattern in the direction in which it is pointing,
and tends to reject signals from above and below, sides and rear.
Depending on the size/gain of the antenna, your pattern might be 60
degrees down to 10 degrees or so. The more the better. Antennas at 2.4
are relatively small and lightweight and little wind loading.

Read the antenna article in the White Papers section of our website
for more info on antennas, gain, and why it matters.

Steve


************************************************** *******************
Steve Uhrig, SWS Security, Maryland (USA)
Mfrs of electronic surveillance equip
website http://www.swssec.com
tel +1+410-879-4035, fax +1+410-836-1190
"In God we trust, all others we monitor"
************************************************** *******************


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