My reply was strictly tongue in cheek as to the amount of range increase that would be obtained. As the other poster claimed that adding 100 feet to some unknown antenna height would yield an additional 14 miles range.
Free space loss is not going to be a factor in a normal repeater system. Unless of course you are starting out with microwatts of power. After all you only loose 6 db every time you double the distance in free space. There are many other factors that will cause attenuation of the signal that will dominate free space loss. 73 Gary K4FMX > -----Original Message----- > From: Repeater-Builder@yahoogroups.com [mailto:Repeater- > [EMAIL PROTECTED] On Behalf Of Eric Lemmon > Sent: Sunday, August 10, 2008 11:42 PM > To: Repeater-Builder@yahoogroups.com > Subject: RE: [Repeater-Builder] Height Gain figure > > Probably not. The range of any repeater or base station is limited by the > ability to receive a signal from the units in the field, not by the amount > of power at the base or repeater station. At some point, the free-space > losses will prevent the unit in the field from getting a usable signal > into > the base station- even if there is a line-of-sight path. This doesn't > happen very often, due to the curvature of the earth, but it is a physical > barrier that exists. We often assume that a line-of-sight path is a > guarantee of solid communications, but it doesn't work that way. After > all, > you can't use a handie-talkie on the moon to talk through a repeater on > Earth, even though you might have a clear line-of-sight path. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer > Sent: Sunday, August 10, 2008 9:20 PM > To: Repeater-Builder@yahoogroups.com > Subject: RE: [Repeater-Builder] Height Gain figure > > So if the antenna is already at 1000 feet height and it is moved up > another > 100 feet to 1100 feet, you are going to increase the range by 14 miles?? > > > > 73 > > Gary K4FMX > > > > > > ________________________________ > > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Sunday, August 10, 2008 3:20 AM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] Height Gain figure > > > > It is interesting to see the many responses, none of which I have problems > with, but all seem to skirt your question. If you are moving the site any > distance from the present site, then it is very true that these variables > must be considered. If you are moving only a very short distance from > your > current site, then, I believe what you are looking for is a simple formula > to givr a close guess of what to expect. I think you will find that > should > yout take the square root of the change in height, in this case, the > square > root of 100 which is 10, and mulitply that by the square root of 2, which > is > 1.414, you will come up with an approximattion of 14 or so miles > improvement. Again, as others have pointed out, many variables inter into > the equasion, but then, the bumble bee can not fly either. . . .. > > > > Hope this helps. > > 73 and cheers, > > Gene, W4FWG > > ************ > > -------------- Original message from Chuck Kimball > <[EMAIL PROTECTED]>: -------------- > > At one point I had read a number for figuring out the gain you get > by > increasing the height. Of course at the moment I'm unable to locate > that. > > ie: If I move the same antenna (VHF 2m) up a hill and gain 100' of > elevation, but it costs me the line loss (300'), did I really gain > anything. > I'll figure in the line loss, and adjust the hardline to minimize > the > loss, but I'm looking for the number to compare how much gain (in > db) > did I get with the increased height. > > So... Anyone know what number is for gain as a function of height? > or > know a reference I can look up. > > Thanks > Chuck > n0nhj > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > >
