I heard that a wire fence, and other forces of electromagnetic energy may distort gps reception and communication. What specifically am I to look out for.
I just set this installation this week, and installed on the roof a metal rod that atop sits the base. Right next to it is a TV satellite dish, and on the right a clothesline, with a metal extension.
Hopefully it won't interfere with land measurements.
I'm sure I could take a look and give you some advice, all I need is a ticket for the plane trip;)
In my experience nearby flat (especially metal) surfaces (walls, etc) that extend above the antenna are a problem, but you should be OK with that setup. I have not found nearby wires to be problematic unless they're energized. You might consider adding some braces to that mast. Looks like a good place for a rooftop deck and some chairs.
That tree to the south of the set-up looks as though it might take quite a chunk out of the sky view.
If the nearby fence is chain link expect plenty of problems. The wire is arranged in a diagonal grid with straight lengths in the order of 1/2 the GPS wavelength. Your antenna is very likely a patch with dimensions of 1/2 or 1/4 GPS wavelengths. Modern small antennas do not have significant ground planes and you may get quite a bit of multipath even from a fence lower than the antenna. The 90å¡ configuration of the wire forms a dipole antenna and at half wavelength is perfect for receiving GPS signals. If it can receive it can also interfere.
I did a test a few years ago, mounting an antenna in the upside down position and got an OPUS solution.
Paul in PA
Paul,thanks for that information. I've always stayed away from C-L fences with my receivers in the assumption that the flatness, density and pattern of the wires would cause it to act much like a flat reflective surface. Never realized it could also act as an antenna.
An R8 like that is not going to have any problems whatsoever from a fence that's that far below it. I agree that the tree on the right looks like it could cause problems, and I agree that I'd brace that pole.
If you guys are talking about the property's boundaries, right before the bloomy yellow flowered field, then this is not a wire fence, its a cement wall and on top of it are wooden stakes.
As for the tree it is a century old geezer, cannot cut it down or trim it. Do you suggest i move the pole on the further left as you in the picture? I did some first tests and i can easily get 9+9 (GPS/GLONASS) SVs though.
The farther away from the tree you can move it the better. That way you can save that shady spot for your beach chair and ice cold cerveza and lime.
Just because I'm paranoid, doesn't mean they aren't out to get me.
Yes but the way that i am now, i can chill under the shade and still keep an eye out closely at my kick-ass trimble dish.
It's always important for a base like that to chart obstructions. Locate each tree and building that is "in the way" then you can chart just where satellites will be interfered with. It may be that the tree is actually under 15 degrees and you can just use a mask of 15 to keep the receiver from looking at satellites lower than that.
By locate, turn a rough AZ and vertical to each obstruction and plot them to a chart, using an inclinometer and compass should be good enough for this exercise.