Ralph, I am sure the equation is
Distance (in miles) = Square Root of (2 * height >> in feet) not Distance (in miles) = Square Root (height in feet). >From: Ralph Mowery <[EMAIL PROTECTED]> >Date: 2007/08/30 Thu PM 12:12:53 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program >Available > > >--- 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/ > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
