antenna alignment

[shabba]

Hi,

I was wondering in what plane the antennas should be? Ie. Are they truly omnidirectional or is vertical or horizontal better? I want to decide how to place some sensors that will be semi permanently installed and don't want to do too much trial and error!

Thanks muchly!

[Rod MacPherson]

In general, the way radio works you will get best performance with the antennas on both send and receive on the same orientation, (in radio terms this is called vertical or horizontal polarization) but that should not make much difference with these radios. If you are trying to go a long distance for an outdoor application you might want to try the slightly more expensive version with the SMA removable "rubber duck" antenna. There is a video series on Youtube where a guy was testing the range of these radios for use in RC aircraft models. With the small one he was able to transmit/receive at a distance of 100m reliably, with the rubber duck I believe it was around 700m. and with a circular polarization wire antenna about the same, but reliability went up.

They do seem to be sensitive to interference from anything at all in the line of sight, so if you have old plaster walls or concrete block to go though you might consider the stronger radios as well.

nRF24L01 range test (arduino) – 17:36
— iforce2d

[daulagari]

@shabba You ask for the plane for the antenna but to for that it is handy to describe your house or setup, one or multiple floors, concrete walls etc?

[shabba]

The sensor I'm using is a reed switch at front gate about 100feet away. The gateway is in a front room. The signal reaches but I just wanted to make sure before I install the sensor in the gate box (electric gate so has outdoor box I can put sensor in and power!) that I do it as optimally as possible.

[daulagari]

If the sensor and the gateway are at the same level or about the same level I think using a half-wave dipole or "rubber duck" antenna pointed vertically is a good idea.

That will focus the energy in the horizontal plane and not into the ground or to the air giving about 2 dBi of gain.