If the hill is just a bump of 40-50 ft above ,say, the rest of the town- and you go up 60 more feet- you will probably be fine with almost any omni antenna.
BUT- if your "hill" is several hundred high (around here we have "hills" 800 ft high or so) then you will go right over your intended users if you use a high gain antenna.
In that case, you should probably use an antenna with electrical downtilt, like the Comet GP24-3. The -3 means it has 3 degrees of downtilt. We buy them at http://www.visradio.com/ and they have the best price we have found.
That made all the difference in the world on one of our Atlanta Freenet nodes.
To learn about downtilt calculations, see http://www.decibelproducts.com/Calculators/downtilt.htm
Try some calculations with various numbers and look how the lobe is "over horizon" when you have no downtilt.
A sample calculation might be: 150 ft HAAT and a 6 degree vertical beamwidth antenna.
Even with 3 degrees of electrical downtilt, the upper lobe of the signal is barely over the horizon.
With NO downtilt, your main lobe never even hits the ground until 17 KM away!!!
That's way further than your power will probably take you.
Ralph N4NEQ http://ralphfowler.com
At 08:13 AM 11/23/2003, you wrote: Begin Quoted Text
A house I am thinking of buying is on a hill. In north western NJ.The owner wasEnd Of Quoted Text
a ham radio operator and there is a 60 foot tower on the property.
I thought about a free networks node, of course.
With an Omni antenna, is the height a good thing like I think. What kind of
range do you think I can get if I stick an antenna on top of a 60 foot high
tower, assuming no other obstructions like buildings that are higher? I assume
the way to do it would be to run cat5 up the tower and use a short cable from
the AP to the antenna on the tower.
This area is rural, 5 and 6 acre lots. Could I cover my whole property with one
AP? How about hitting the neighbors down the street??
Interesting question? I realize most of the people on this list have experience
in urban installations, where you can't get line of sight for 100 feet.
Fred
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