I have 2 SA24-120-16 antenna's on a tower. Still learning alot about wireless broadband as I go. currently they are at the same height on the tower and near each other. Can this cause interference and if so, how far apart should they be vertically and horizonatlly. They are set for a vertical polarity.
Thanks!
Antennas do not cause interference. Radios cause interference.
So far, all I know is that there are two antennas on a tower at some unspecified seperation and orientation. No clue as to how much coax is between the antennas and their respective radios, what type of radios, length of coax cables, and whether this is part of some power splitter or amplifier arrangement.
The RF-Linx SA24-120-16 is a 120 degree sector antenna, with 16 dB of gain. If you mount these next to each other, but rotate them so that the 120 degree sector pattern does NOT overlap, you will probably have enough isolation between antennas. If you look at the typical cellular monopole, that's the way they do it. 3ea 120 degree sector antennas wrapped around the pole.
The point at which your unspecified receiver overloads is in the data sheet. -30dBm is typical. If you do have overlap, you can use the antenna patterns:
-30dBm, you will have a desensitization problem. Note that the interfering transmitter does NOT need to be on the same channel.
A more serious and incidious problem is intermodulation products caused by two transmitters mixing together. This can easily happen when two or transmit antennas are too close. In commercial VHF/UHF systems, isolators, circulators, and cavities are used to provide additional isolation. These are not very economical at 2.4Ghz, so physical isolation is necessary.
Rant: Numbers and specifics, not prose.
"me" | I have 2 SA24-120-16 antenna's on a tower. Still learning allot about | wireless broadband as I go. currently they are at the same height on the | tower and near each other. Can this cause interference and if so, how far | apart should they be vertically and horizontally. They are set for a | vertical polarity.
I'd need a bit more info to make an educated response but with what you have posted:
Horizontally spaced antenna typicallky experience more mutual interference than vertically spaced antenna. The idea configuration would be vertical spacing coaxially in line.
That said there are two type of potential interference. The first has to do with RF reception and is frequency/channel dependant. The second has to do with parasitic reradiation. In some cases this is the desired effect and produces directivity. In other case it can cause multi-plathing which is typically (but not always) undesired.
Sector antennas dont have near the problems as other antenna types. I see sectors on antennas all the time mounted 6 at a time. Are you experiencing interference or just curious. Are they on the same channel?
Simply, in theory you should place your antennas about 120-300cm horizontally from each other, and at least half of their length in vertical.
This is, of course, only theory. Everything depends on your radio's output power. When talking about wifi I think that a couple of centimeters is enough. (tested) But it also depends on antenna's F/B ratio...
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