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Doc,
He was 5 miles from the repeater. I was around 100 miles from the repeater. I also opened (and tried a quick call) over a repeater in Pennsylvania. This was from Rochester, NY (almost at Lake Ontario). In other words, I was transmitting successfully to another repeater in another state(and that one was *well* over 100 miles away) ![]() BTW, two folks could well be on opposite sides of the repeater. Should the other guy happen to have a high elevation (as did I), then communications approaching 200 miles between the HTs (100 miles to the repeater plus another 100 miles to the other guy) are possible (but only in *unusual* circumstances). My former neighbor lives on a 2200 foot "hill" and I am certain she would have one heck of a range. I am only considering the range I can obtain to a repeater. Granted, the repeater antenna gain is pretty high, but it would likely not be more than 10 dB over my 36 inch gain antenna. So, between similar HTs, cut the distance 1/3 (1/9th the power) and I'd still expect well over 30 miles (and not need as much height, but still both would have to be located fairly high above average terrain). Simple math, as long as you've got a clear shot. The satellites are not running kilowatts either, you know ![]() 73 from Rochester, NY Jim "'Doc" wrote in message ... Jim, If you both were using the repeater, then you were both in range of the repeater. You weren't talking direct, so not the same thing. 'Doc --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.502 / Virus Database: 300 - Release Date: 7/18/03 |
#12
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Doc,
Normally, HTs will be limited to line of sight. The problem is that normal line of sight is only about 3 miles to radio horizon for a person standing on level ground. Get up on a ladder, and the horizon stretches out farther. We're not talking propagation enhancements, just a simple formula which takes the station's height above average terrain (in feet), double that and take the square root. The answer is the range to radio horizon. 5 feet (to a handheld antenna) times two is 10. SQR(10) is a bit over 3 miles. 6 or 7 miles max. Get in the second story of a house. Figure 11 feet (up a few feet to the first floor, another 8 or so to the second floor) and add that 5 feet from that floor to the HT. Now 16 doubled is 32. The square root of that is somewhat over 5. I would suspect a range of 10 to 12 miles between two handhelds equally elevated over average terrain in that case. I was on the 21st or 22nd floor of a high rise. Figure over 200 feet up, plus 600 feet above average terrain (yes, it was on a hill). 800 feet and I won't add the extra 5 feet. SQR(1600) yields 40 miles to radio horizon. Now figure in the repeater height. Should that repeater be up a total of 2000 feet (including hill, tower, antenna, whatever), it will have a range over 60 miles to its' horizon. As long as my horizon intersects its' horizon with no obstruction, I can use that repeater. The 3.5 watts on my HT is not a problem; my antenna gain is around 6 dBi and I'm sure the repeater antenna gain is way over 10 dBi. Plenty of power. I'm talking 24/7 communications. I've had a few chats over (and can raise at any time of day) the Toronto repeater. Definitely more than a couple of miles. Way more than a couple of dozen miles too ![]() 73 from Rochester, NY Jim "'Doc" wrote in message ... Jim, So, are you saying that range is unlimited at UHF as long as it's 'line of sight'? Assuming that the transmitter's output for both radios are the same, and both receiver's sensitivity is the same, and both have a usable range of 3 miles. That means for the two stations to hear each other they have to be within three miles of each other. At 6 miles neither will be able to hear the other because they would both be out of each other's usable range. Wouldn't matter what the 'line of sight' distance was. Propagation will make a difference, but we're talking about the 'normal', every day state of propagation. 'Doc --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.502 / Virus Database: 300 - Release Date: 7/18/03 |
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