Video Conference Wireless Bridge Hardware Set Up

ZioPRoTo · 12-20-2004

Hello,

we have two video conference machines that work over IP and have a RJ-45 ethernet interface or a RJ-11 ISDN interface.

Because they also work over a ISDN network they need very little bandwith, much less than 100Mbit/s. So we thought to use them on a 802.11 network segment, to avoid the cost of using the ISDN network.

What about this hardware? D-Link DWL-2100AP, that has a SMA connector, and we want to put parabolic grid antennas. If necessary also we can use some other AP on the way as repeater. Let's say we need to do a 3Km link in a urban environment. Is this AP suitable for the job? Is any AP suitable for this job or we need an AP with some specific function?

In the past I only used APs for talking to clients, never configured and AP to talk to other APs. I think the 2 end point of the connection must be set as root AP and the rest as repeater?

I'm a little confused, I know the post il generic and I might be blamed, but on the net there is also a lot of confusing docs, so if someone could post some hot links would be very appreciated.

Anyone used D-Link DWL-2100AP for such jobs already?

Thanks

ZioPRoTo

Thorn · 12-20-2004

The first question isn't whether "Brand X" will do a particular job. Rather, it is: Does a path analysis show that you can do a 3km path in an urban environment at all? Due to the way most urban environments tend to be, the answer to that is "Probably not." You need a clear RF-LOS, which means a clear Fresnel Zone. At 3km, the FZ works out to be approximately 8-10m diameter. That means your dish antennae would have to be 8-10m above any structures between the two dishes.

When you have done the path analysis, and determined if you have the RF-LOS and a clear FZ, then compute the link budget. When you have the figures for the link budget, then you can look at the specifications and see if particular brands/models will work for you.

Always "do the math" first. Otherwise, you're spinning your wheels.

ZioPRoTo · 12-20-2004

I didn't figure that RF-LOS was so important

I thought it was possibile to make it passing through buildings...

Thanks a lot! I went back to read my FZ notes of a couple of years ago

ZioPRoTo

12-20-2004	#1 (permalink)
ZioPRoTo Registered Member Join Date: Jun 2004 Posts: 34	Video Conference Wireless Bridge Hardware Set Up Hello, we have two video conference machines that work over IP and have a RJ-45 ethernet interface or a RJ-11 ISDN interface. Because they also work over a ISDN network they need very little bandwith, much less than 100Mbit/s. So we thought to use them on a 802.11 network segment, to avoid the cost of using the ISDN network. What about this hardware? D-Link DWL-2100AP, that has a SMA connector, and we want to put parabolic grid antennas. If necessary also we can use some other AP on the way as repeater. Let's say we need to do a 3Km link in a urban environment. Is this AP suitable for the job? Is any AP suitable for this job or we need an AP with some specific function? In the past I only used APs for talking to clients, never configured and AP to talk to other APs. I think the 2 end point of the connection must be set as root AP and the rest as repeater? I'm a little confused, I know the post il generic and I might be blamed, but on the net there is also a lot of confusing docs, so if someone could post some hot links would be very appreciated. Anyone used D-Link DWL-2100AP for such jobs already? Thanks ZioPRoTo __________________ See my stupid personal web site! http://zioproto.serveftp.com

12-20-2004	#2 (permalink)
Thorn Did you do the math? Join Date: Apr 2002 Location: Villa Straylight Posts: 10,361	The first question isn't whether "Brand X" will do a particular job. Rather, it is: Does a path analysis* show that you can do a 3km path in an urban environment at all?* Due to the way most urban environments tend to be, the answer to that is "Probably not." You need a clear RF-LOS, which means a clear Fresnel Zone. At 3km, the FZ works out to be approximately 8-10m diameter. That means your dish antennae would have to be 8-10m above any structures between the two dishes. When you have done the path analysis, and determined if you have the RF-LOS and a clear FZ, then compute the link budget. When you have the figures for the link budget, then you can look at the specifications and see if particular brands/models will work for you. Always "do the math" first. Otherwise, you're spinning your wheels. __________________ Thorn "Read Altas Shrugged. Compare it to today. Repeat as necessary"

12-20-2004	#3 (permalink)
ZioPRoTo Registered Member Join Date: Jun 2004 Posts: 34	I didn't figure that RF-LOS was so important I thought it was possibile to make it passing through buildings... Thanks a lot! I went back to read my FZ notes of a couple of years ago ZioPRoTo __________________ See my stupid personal web site! http://zioproto.serveftp.com

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