Re: Re: Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available
Ralph, The equation you gave from ARRL was dist=sqrt(2*height) Sqrt of 2 is 1.41 Sqrt (2 * H) = 1.41 *sqrt(H). Just bring out the sqrt of 2 first, hi. 73, ron, n9ee/r From: Ralph Mowery [EMAIL PROTECTED] Date: 2007/08/30 Thu PM 05:52:43 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available --- Ron Wright [EMAIL PROTECTED] wrote: 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). Then my refferance (ARRL Antenna Book 1974 version page 11) must be wrong. They give it as 1.415 * sqrt height, not 2 times the heigth. You may be getting the two times if you have two antennas at the same height. You have to use the formula two times, one for each antenna and then add them together for the total distance. The 1.415 is a multiplier for radio wave bending around the curve of the earth and may need to be differant for differant kinds of earth. __ Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available
Nate, Totally aggree with you. HAAT, true HAAT, is the real factor. Coverage of a repeater is determined by HAAT. I've been told by a repeater owner and users a repeater is say 850 ft high. Turns out they were giving referenced to ASL and the ground ASL was 800 ft, hi. Kinda down the same lines as one stating when they are monitoring a repeater a user will turn their beam in the direction of a users location. 73, ron, n9ee/r From: Nate Duehr [EMAIL PROTECTED] Date: 2007/08/30 Thu AM 03:44:32 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available On Aug 30, 2007, at 1:20 AM, MCH wrote: Height = elevation AMSL of the antenna, HAAT, or AGL (which would make no sense)? I assumed HAAT for my calculations and that number seemed to be the most sane, after trying a few. But I think the resulting number is generous for a badly-built repeater, and too small for a well-built one. -- Nate Duehr, WY0X [EMAIL PROTECTED] Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available
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 Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
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/
Re: Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available
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.
Re: Re: Re: [Repeater-Builder] Re: Repeater Range : Estimate Program Available
--- Ron Wright [EMAIL PROTECTED] wrote: 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). Then my refferance (ARRL Antenna Book 1974 version page 11) must be wrong. They give it as 1.415 * sqrt height, not 2 times the heigth. You may be getting the two times if you have two antennas at the same height. You have to use the formula two times, one for each antenna and then add them together for the total distance. The 1.415 is a multiplier for radio wave bending around the curve of the earth and may need to be differant for differant kinds of earth. Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting
