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Old March 18th 04, 12:22 AM
DougSlug
 
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Default 2.4 GHz Antenna

I am looking into setting up remote monitoring of a lab at my
company using 2.4 GHz wireless cameras. The monitoring location would be
in a nearby building (a few hundred feet away across a small parking lot).
I know the range of those cameras is not very far, so I'm wondering if
anyone has any experience using any directional antennas (such as those
used for WiFi or the LPY2 "log periodic Yagi" from Ramsey Electronics) to
increase range on the receiver end. Assuming the stock transmitter
antennas are pointed toward the monitoring location, is there any chance I
could get this to work? Recommendations for specific antenna models are
also appreciated. I am planning on using an AOR AR-8600MkII receiver with
NTSC decoder board since the cameras are of different makes and the
channels they use vary across manufacturers.

TIA,
Doug


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Old March 18th 04, 03:05 AM
krackula
 
Posts: n/a
Default

don't use those 2.4 gig wireless cameras. they will only end up
causing you grief. instead set up a standard WAP / wifi setup and
transmit the pictures using the common ( and cheap on ebay ) remote
web / net cameras. you can remote control those, access the cameras
anywhere from your office or home network / router / or web , store
the pics on your computer, and transmit the network long distances
using standard , off the shelf , WAP / wifi equipment... available at
best buy or good guys.

with this more desirable approach , no one can sit in your parking lot
and watch everything YOU are seeing , thereby compromising your
security and activities ...plus you avoid the EXTREMELY irritating
circumstance of buying the equipment , installing the equipment and
suddenly finding out that any tom dick or harry with a common
2.4 gig spread spectrum cordless phone will wipe out your entire
wireless video system, and render it useless every time they power up
the phone. ( they will sweep the camera receiver freqs and tear your
video sync signals and make your video stream useless. )

the bubble of a common WAP net ( range ) can be from a few
square blocks to 20 miles ..depending upon what you buy to install.
stuff to do all of this is VERY affordable on ebay.

it's , simply put , a standard wireless office setup , using standard
web cams ... ! also good for upgrading your office net too.


k.......................



On Thu, 18 Mar 2004 00:22:06 GMT, "DougSlug"
wrote:

I am looking into setting up remote monitoring of a lab at my
company using 2.4 GHz wireless cameras. The monitoring location would be
in a nearby building (a few hundred feet away across a small parking lot).
I know the range of those cameras is not very far, so I'm wondering if
anyone has any experience using any directional antennas (such as those
used for WiFi or the LPY2 "log periodic Yagi" from Ramsey Electronics) to
increase range on the receiver end. Assuming the stock transmitter
antennas are pointed toward the monitoring location, is there any chance I
could get this to work? Recommendations for specific antenna models are
also appreciated. I am planning on using an AOR AR-8600MkII receiver with
NTSC decoder board since the cameras are of different makes and the
channels they use vary across manufacturers.

TIA,
Doug


  #3   Report Post  
Old March 18th 04, 03:12 AM
Steve Uhrig
 
Posts: n/a
Default

On Thu, 18 Mar 2004 00:22:06 GMT, "DougSlug"
wrote:

I am looking into setting up remote monitoring of a lab at my
company using 2.4 GHz wireless cameras. The monitoring location would be
in a nearby building (a few hundred feet away across a small parking lot).
I know the range of those cameras is not very far, so I'm wondering if
anyone has any experience using any directional antennas (such as those
used for WiFi or the LPY2 "log periodic Yagi" from Ramsey Electronics) to
increase range on the receiver end.


Don't mess with amateur toys if you are trying to do a real job.

Go to a commercial supplier such as Tessco or Tecom and get antennas
made for professional use.

Assuming the stock transmitter
antennas are pointed toward the monitoring location, is there any chance I
could get this to work?


If there is *nothing* between the antennas other than atmosphere, a
few hundred feet is fine. Get a gain antenna for the receiver and
point it at the transmitter to null out as much of the many many other
signals you will find on the 2.4 ISM (Industrial, Scientific and
Medical) band, aka the garbage dump.

I am planning on using an AOR AR-8600MkII receiver with
NTSC decoder board since the cameras are of different makes and the
channels they use vary across manufacturers.


This will give you soft video.

The *make* of the camera doesn't matter. The frequency of the
transmitters and receivers do, and if you are running more than one
link you need a good bit of frequency separation.

I recommend equip and antennas from www.microtekelectronics.com. They
are reasonably honest with their specs, equip is about the best
quality without going to government spec, and they have some decent
antennas.

Put the transmitter and receiver right at the antenna and run the
video up and down from them. There is much less feedline loss at video
freqs than the 2.4 gig RF freqs. A few feet of antenna feedline is
about the max you can get away with. The Microtek stuff can withstand
the elements. Mount everything in a piece of PVC pipe to weatherproof
it.

I'm not affiliated with Microtek in any way.

You can buy Microtek from www.atvelectronics.com. Ask for Dan Potts.
They sell to dealers or to competent self maintaining end users who
will not need support.

There are some wireless video articles in the White Papers section of
our website which may be helpful.

Don't buy consumer junk or stuff from spy shops or you will be wasting
your money.

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"
************************************************** *******************
  #4   Report Post  
Old March 18th 04, 05:20 AM
krackula
 
Posts: n/a
Default


http://cgi.ebay.com/ws/eBayISAPI.dll...tegory=43 461





On Thu, 18 Mar 2004 03:05:18 GMT, krackula wrote:

don't use those 2.4 gig wireless cameras. they will only end up
causing you grief. instead set up a standard WAP / wifi setup and
transmit the pictures using the common ( and cheap on ebay ) remote
web / net cameras. you can remote control those, access the cameras
anywhere from your office or home network / router / or web , store
the pics on your computer, and transmit the network long distances
using standard , off the shelf , WAP / wifi equipment... available at
best buy or good guys.

with this more desirable approach , no one can sit in your parking lot
and watch everything YOU are seeing , thereby compromising your
security and activities ...plus you avoid the EXTREMELY irritating
circumstance of buying the equipment , installing the equipment and
suddenly finding out that any tom dick or harry with a common
2.4 gig spread spectrum cordless phone will wipe out your entire
wireless video system, and render it useless every time they power up
the phone. ( they will sweep the camera receiver freqs and tear your
video sync signals and make your video stream useless. )

the bubble of a common WAP net ( range ) can be from a few
square blocks to 20 miles ..depending upon what you buy to install.
stuff to do all of this is VERY affordable on ebay.

it's , simply put , a standard wireless office setup , using standard
web cams ... ! also good for upgrading your office net too.


k.......................



On Thu, 18 Mar 2004 00:22:06 GMT, "DougSlug"
wrote:

I am looking into setting up remote monitoring of a lab at my
company using 2.4 GHz wireless cameras. The monitoring location would be
in a nearby building (a few hundred feet away across a small parking lot).
I know the range of those cameras is not very far, so I'm wondering if
anyone has any experience using any directional antennas (such as those
used for WiFi or the LPY2 "log periodic Yagi" from Ramsey Electronics) to
increase range on the receiver end. Assuming the stock transmitter
antennas are pointed toward the monitoring location, is there any chance I
could get this to work? Recommendations for specific antenna models are
also appreciated. I am planning on using an AOR AR-8600MkII receiver with
NTSC decoder board since the cameras are of different makes and the
channels they use vary across manufacturers.

TIA,
Doug


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Old March 18th 04, 01:28 PM
DougSlug
 
Posts: n/a
Default

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.





  #6   Report Post  
Old March 18th 04, 04:09 PM
krackula
 
Posts: n/a
Default


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.



  #7   Report Post  
Old March 18th 04, 05:35 PM
Steve Uhrig
 
Posts: n/a
Default

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"
************************************************** *******************
  #8   Report Post  
Old March 18th 04, 05:53 PM
Steve Uhrig
 
Posts: n/a
Default

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"
************************************************** *******************
  #9   Report Post  
Old March 21st 04, 03:05 PM
Xanax
 
Posts: n/a
Default

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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  #10   Report Post  
Old March 21st 04, 07:06 PM
Waterperson77
 
Posts: n/a
Default

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.


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