--- Ron Wright <[EMAIL PROTECTED]> wrote:
>
>
> >
> >
> >On Aug 30, 2007, at 12:35 AM, ldgelectronics wrote:
> >
> >> As a quick and dirty method, the radio horizon
> is:
> >>
> >> Distance (in miles) = Square Root of (2 * height
> in feet).
> >
>
> This equation is ok, but for a perfect spheer. Is a
> good place to start. Here in FL where max altitude
> is about 330 ft ASL it works pretty well although
> the lower the antenna the worse the actual coverage
> results. We have plenty of repeaters at 200 ft that
> have noticably better coverage than 20 miles with a
> mobile.
>
> Also one has to take in account of the user's
> station. The equation is to the horizon so a user
> with height over the horizon can also increase
> coverage.
>
> 73, ron, n9ee/r
>
>
The quick and dirty method at the top is not entirely
correct. For relative flat land the visual range to
the horizon in miles is the sqrt of the height in
feet. That is just for one station. You have to do
the same for the other station and add the results
together. Then there is a factor of about 1.2 to 1.5
this distance has to be multiplied by for the radio
horizon instead of the vusual horizon.
For the repeater station antenna at 200 feet, it would
be 14 miles to the horizon plus a mobile antenna of 5
feet heigth to get 2.2 miles which would be 16.2
miles. Then multiply that by the radio wave bending
factor of 1.2 to 1.5 to get 19.4 to 24.3 miles.
It does not take much of a rise in the road when the
rest of the land is flat to get the mobile station up
a few feet and this can add a lot to the range. If
the road goes up just 25 feet more the range will go
up around 5 more miles.
____________________________________________________________________________________
Pinpoint customers who are looking for what you sell.
http://searchmarketing.yahoo.com/
