How to obtain height above terrain information for local repeaters

[KE5RKE]

Planning my first antenna mast. Trying to decide how tall to "reach" to put up my base antenna for 2-Meter operation. I'm having trouble locating height above terrain information about specific repeaters in my local area. Where would I go to find that information?

73's
Chris
KE5RKE

 

[tweiss3]

You are going to have to email the club/owner. Most are pretty helpful and will provide that information pretty readily.

 

[AK9R]

Antenna height above ground and antenna height above average terrain (HAAT) are two different things and can be very different depending on the terrain. Most repeater owners know their antenna height above ground, but not all of them know their HAAT. The FCC has a handy calculator for HAAT at Antenna Height Above Average Terrain (HAAT) Calculator. You input the antenna's lat/lon and the antenna height above ground (in meters) and it will calculate HAAT.

 

[KE5RKE]

You are going to have to email the club/owner. Most are pretty helpful and will provide that information pretty readily.

Thanks for that. The problem is, in this case, I don't know the owners of the ones I can't seem to find the height on.

Antenna height above ground and antenna height above average terrain (HAAT) are two different things and can be very different depending on the terrain. Most repeater owners know their antenna height above ground, but not all of them know their HAAT. The FCC has a handy calculator for HAAT at Antenna Height Above Average Terrain (HAAT) Calculator. You input the antenna's lat/lon and the antenna height above ground (in meters) and it will calculate HAAT.

Thanks for the link for HAAT. Wasn't aware of that one. That sounds like something that would take care of my questions.

 

[KE5RKE]

Well, guess I'm not too bright. Can't figure out how to use the HAAT program. Coordinates were 35 08 18 N, 97 39 27 W. Calculations showed the antenna was below sea level. I don't think so!

 

[AK9R]

If I use a 33 meter antenna height at that location, I get -348 meters HAAT. That means that the antenna's height above the average terrain is actually 348 meters below the average terrain. Sounds like the location is in a river valley.

 

[KE5RKE]

Well, I'm "guess-T-mating" the height at 10 meters. From Google Earth it looks like about a 30' tall Rohn tower. I can "hit" that repeater with 60 watts from my 20' temporary mast but only get 3 "bars" return signal on my Icom-2200H.

I took AK9R's suggestion and searched out the controlling club and person in charge and sent him an email. Obviously that will get me a correct answer. But I'd still like to know how to properly use that HAAT program because it takes into consideration the antenna's height above the ground and all the terrain in-between my antenna and theirs. I think it could be most useful.

 

[WA0CBW]

My calculation show his ground elevation to be 387 meters and his HAAT to be 9 meters. Dont forget to add the existing ground elevation to the actual antenna height.
BB

 

[KE5RKE]

Well, that sounds more like my guesstimate from the Google Earth image. But I don't understand how you arrived at those two figures. ?????

 

[AK9R]

Dont forget to add the existing ground elevation to the actual antenna height.

I sure slipped into that trap, didn't I. I'm used to the ground elevation above sea level being rolled into the antenna height above ground and completely forgot about it.

 

[n9mxq]

I have doubts.. At the top of my tower I look over everything but a few trees (top of the hill) and it has me at -247 HAAT...

 

[WA0CBW]

Your ground elevation comes from the map (along with your lat and long). Make sure you use the correct meter/feet conversations. 9 meters is your ground elevation so add your actual antenna height to that to get your "actual" antenna HAAT.
BB

 

[WA0CBW]

You have to look up your ground elevation (I get mine from DeLorme maps) and add it to your antenna height as per the calculator instructions.
BB

 

[KE5RKE]

Okay, here ya go. I physically went to the gate for the enclosure of the tower for W5NOR in Norman, Oklahoma. I know for a fact the ASL for the enclosure is 1200' ASL. The coordinates marked on the gate are LAT 35.13 1390 N and LON -97.19 4890. (when I put those coordinates into Google Earth, they take me several miles South of that location) I found different coordinates for the same tower....................35.21784W -97.41059W, in a repeater locator, so I don't know what to think! You tell me what the elevation at the top of that tower. Eyeballing it, it looks like a 150' tower.

 

[AK9R]

Lat/lon coordinates are a PITA because there are different formats and sometimes you can't tell which is being used. It could be DD.dddddd which is degrees and decimal degrees. It could be DD MM.mmm which is degrees, minutes, and decimal minutes. Or, it could be DD MM SS which is degrees, minutes, and seconds.

 

[KE5RKE]

Maybe that's where I'm getting side-tracked AK9R. Not too bright on all of this stuff.

 

[WA0CBW]

There are several ways to identify coordinates (hours, minutes, seconds; decimal; etc). Be sure the gate and google are using the same method.
BB

 

[WA0CBW]

Looks like AK9R beat me with an answer but with a more detailed description.

 

[slicerwizard]

Okay, here ya go. I physically went to the gate for the enclosure of the tower for W5NOR in Norman, Oklahoma. I know for a fact the ASL for the enclosure is 1200' ASL. The coordinates marked on the gate are LAT 35.13 1390 N and LON -97.19 4890. (when I put those coordinates into Google Earth, they take me several miles South of that location)

Eh? Google Earth shows a tower at those exact coordinates.

 

[TexTAC]

Here's a trick I learned from Radio Reference forums on a previous post from a long time ago. If you use Google Earth Pro (it's free) you can create an "elevation profile" from one location (i.e. your antenna) to another location (i.e a repeater). To do this, click "add" and select "path". Then use the cursor and mouse click to select point A and again to select Point B. Select "OK" on the popup menu to save the line. Now hover over the line with the mouse until a hand appears, then right click, and select "show elevation profile". It won't give you the antenna height, but it will give you an idea of the elevation profile from one point to another. For example ... Here is a quick elevation profile from Fort Worth to Dallas.