Will there be reflection problems with AP on metal siding?

[glenn.newman]

We are considering mounting a patch antenna on a high wall with aluminum or metal siding at ~ 45 degree angle to cover the ground below. Will we have problems with reflections back to the AP and having different phases of the original signal to the client?

It seems like the AP will have to do some processing if it receives its own signal.

[scottmac]

The only way to know for sure is to try it (ala "site survey").

That being said, I belive you'll be OK with it. A typical patch has a hemispherical pattern (180 degree coverage). If the antenna is oriented to a 45 degree downslope ( |/ ) there will be some multipath, but the phase of the reflected signal should be within acceptable limits for the AP (especially if it is a diversity antenna - two antenna leads to the same antenna module).

You will need to make sure the antenna is mounted ~ 6" from the siding (a little more than one wavelength) to prevent "coupling" the driven element(s) with the metal siding. It may or may not be an issue, depending on the construction of the antenna.

Easier to be safe and mount it out a little bit.

Good Luck

Scott

[chris@routerguy.com]

Hi

If you are using some sort of a sector panel/patch or BBQ grill antenna pointing to the area you want to cover, I have seen little issue with metal behind the antenna.

I run into problems with chain link fences, lots of paper or concrete/cinderblock and whatever in front of the antenna. Warehouses have this effect.

Look for a 120 degree sector panel - not cheap but very effective.