Objective
Our gate opener remote receiver works much better with the antenna horizontal than vertical? By much better, I mean 300' vs 100'. Why?
Background
The distance the remote will operate the gate appears to be independent of time of day, and/or weather conditions.
The antenna is directly connected to the receiver which connects to the gate controller with a 3-wire cable. As best as I can determine the receiver sends remote codes to the controller on one of the 3-wire cable conductors, the other two are for power and common.
Frequency is ~320MHz, and the antenna is ~9” long.
The antenna originally was near vertical, but it sagged under gravity to a more horizontal orientation. I know the antenna will continue to sag and I'm thinking distance will suffer as it becomes more vertical.
I could straighten the antenna to vertical and the range would suffer, I 'know' it is antenna orientation but can't explain it to myself.
Imagery
Best Answer
I'm not an antenna design expert, or an RF guru, but I did quite a bit of work with RF telemetry installations in hospitals using a similar RF band. I also worked with MRI RF systems, head/body coils, etc. Many factors can effect the loading of your antenna system, other conductors, metal fencing, etc. and something like that is probably happening here. If you have a spectrum analyzer you can tune your circuit to optimize the impedance, but I'm guessing that this type of equipment is way overkill for your application. Did you run A/B repeatibility tests to verify something else didn't change? You could probably have one person got to the edge of the remote range, and another person at the antenna, then communicating on your cell phone tune the antenna position for the best possible range. Then definitely fix it so that gravity, wind, etc is not changing the position of your antenna. Good luck.