I'm fairly new to scanning was wondering how to calculate how far a tower will reach
How to tell the range of towers
- Thread starter Nate12
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RR database tells you if you visit a trunked system's database link & click on a site name
Frequency band too - VHF will have more coverage than UHF or 800 Mhz, but less penetration
nd5y
Member
To calculate actual radio range you need a lot of information about the particular system and you need to use something like Radio Mobile WEB Site or SPLAT! A Terrestrial RF Path Analysis Application For Linux/Unix.
The database range circles (like in post #2) are for location-based scanners and have nothing to do with real life radio coverage.
The database range circles (like in post #2) are for location-based scanners and have nothing to do with real life radio coverage.
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Your setup also has a lot to do with reception.
Inside Antenna
Metal Roof
Concrete Building
A Hill or Mountain Between You and The Site
The picture in post #2 the outer edges is also range outside not in buildings
Inside Antenna
Metal Roof
Concrete Building
A Hill or Mountain Between You and The Site
The picture in post #2 the outer edges is also range outside not in buildings
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(Assuming you mean VHF and higher)
A couple points.
1. Setting aside things like troposcatter, skip, aircraft/satellites in space, and power, receiver sensitivity, the main factor is terrain and object in the intervening path (with frequency also having some effect). There is software that takes into account terrain.
2. The antenna height at the other end is just as much a factor.
3. In simplest form, if one assumes a spherical earth and just considers line-of-sight, the range would be:
1.23 x (square_root(h1) +square_root(h2))
where h1 is the transmit antenna height in feet, h2 is the receive antenna height in feet, and the answer is in miles.
Ex. If both antennas are at 100 ft., the line-of-sight range is 24.6 or about 25 miles; but if one antenna is at 100 ft. and the other at 6 feet, the lien-of-sight range will be 15.3 miles. (Do not forget the above assumptions and that most commercial antenna sites are on high ground--one might use height above average terrain to try to take that into account.)
(In the above, remember the mathematical rules of order of operations for the above: Do the parenthesis first (starting with inside ones). Do multiplications before additions and subtractions.
(The above formula comes from adding the distances to the horizon of the two antennas.)
Everything else (factors listed above) increase or decrease this.
A couple points.
1. Setting aside things like troposcatter, skip, aircraft/satellites in space, and power, receiver sensitivity, the main factor is terrain and object in the intervening path (with frequency also having some effect). There is software that takes into account terrain.
2. The antenna height at the other end is just as much a factor.
3. In simplest form, if one assumes a spherical earth and just considers line-of-sight, the range would be:
1.23 x (square_root(h1) +square_root(h2))
where h1 is the transmit antenna height in feet, h2 is the receive antenna height in feet, and the answer is in miles.
Ex. If both antennas are at 100 ft., the line-of-sight range is 24.6 or about 25 miles; but if one antenna is at 100 ft. and the other at 6 feet, the lien-of-sight range will be 15.3 miles. (Do not forget the above assumptions and that most commercial antenna sites are on high ground--one might use height above average terrain to try to take that into account.)
(In the above, remember the mathematical rules of order of operations for the above: Do the parenthesis first (starting with inside ones). Do multiplications before additions and subtractions.
(The above formula comes from adding the distances to the horizon of the two antennas.)
Everything else (factors listed above) increase or decrease this.
Ok I think these answers most of my questions thanks for the help
ecps92
Member
Only you can tell, from your monitoring location.
The Circles in RR are approximate, to help with the folks using GPS to change systems in-range
The Circles in RR are approximate, to help with the folks using GPS to change systems in-range
west-pac
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These coverage circles are literally just a guess; sometimes educated, sometimes not. The RR Admins add that range/mileage figure. Some RR Admins guess better than others. Every site has a different actual range, but you'll notice a lot of sites on the same systems, worked by the same Admin, will have the same range figure simply because that is the range figure that specific Admin has chosen to use for every site.
Honestly the best way to tell is to do a lot of driving, if you travel with scanners a lot you will fairly quickly figure out good and bad locations to receive various towers. It can be a tad time consuming but if I'm traveling through a new area I will usually stop somewhat frequently, especially at high elevation areas, and run the scanner in band search mode to see what control channels I can receive from a particular location. I hardly ever use the GPS thing, I absolutely hate it because it's "pretend roaming", it's not based on actual signal levels (i.e. RSSI, BER etc).
ChrisABQ
...
This site is a great tool.
Ubbe
Member
Coverage circles are a compromise to have something to listen to when you travel thru unknown territory. There will always be buildings and hills that change the actual coverage and also if you are down low or up on a hilly area and what type of antenna you have. Sometimes the position of a tower and its coverage are not correct in the database. I noticed that the database had one tower positioned in the middle of a swamp while FCC had the coordinates for the same site more than 10 miles away at the top of a hill.
If scanning from home, or you always travel thru the same areas, then make favorite lists of the areas and use the service types to select what type of monitoring you would like to do at that time.
/Ubbe
If scanning from home, or you always travel thru the same areas, then make favorite lists of the areas and use the service types to select what type of monitoring you would like to do at that time.
/Ubbe
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