Antenna Height

[simcor23]

This is sort of a question for anyone in the southern ontario region,

I am trying to work out a 25 mile link for a customer, there is only 100ft tower on each side. both sites are pretty much the same above ground level give or take about 6 feet. Does it sound possible to get a link with those heights. I will be using 29dbi dishes starv3 on both ends with cm9's 5.8ghz. For anyone living in the soutern ontario region the link goes pretty much paralell to the 401 just so you know the approximate terrain???

[tog]

At 100 feet on both ends that should be possible with ideally about a -68 signal.

As long as the terrain isn't hilly or mountainous with large variations in the actual height between the two.

[go.fast]

I am trying to work out a 25 mile link for a customer,
there is only 100ft tower on each side.
both sites are pretty much the same above ground level give or take about 6 feet.
Does it sound possible to get a link with those heights.
I will be using 29dbi dishes starv3 on both ends with cm9's 5.8ghz.

You need to find the calculation that will tell you the size of the fresnel zone in the middle and then calcualte how much is being infringed upon.

I'm not sure where to find the calculator, but maybe some one that has a formula handy can post it for eveyone to have.
Maybe add it to wiki

George

[tog]

http://www.ecommwireless.com/cgi-local/wireless.main.cgi

[lonnie]

Just use http://www.cplus.org/rmw/english1.html

No point guessing and it'll show you the precise path and even give you an estimate of the signal.

[Stratolinks]

You can do all the math in the world but it still won't tell you what is in between the locations. Best bet is to look at the path on a topographical map to determine if there is higher ground in betwwen the points, then add enough for trees to be on the higher ground and then enough for your fresnel zone. Once you know there is clearance then the math will tell you what antennas and feedlines are needed to make it work.

I have one location just North of London where we have equipment 364ft up a Bell Canada tower and a few customers that are 2km away have to put up 64ft towers to clear the trees that they are behind. Another customer that is 2k from another site that is 156ft up and can't see it from his 50ft tower, but he can see the 364ft Bell tower that is 15km away while standing on the ground.

In Southern Ontario the terrain is far from level. On a clear day, from the above Bell tower, I can clearly see the Canada Cement building that is South of Embro, (a distance of 37km) with the naked eye.

In this business, topography is your best friend and your worst enemy.

[sligbot]

I totally agree. It's really difficult to say, especially how the terrain works in Southern Ontario. Some places have some wicked hills and with just a few trees on them, well, your 5GHz signal would stop dead. Sometimes a good path analysis is what's necessary...