Metal screen, hardware cloth. The squares need to be 10% of the wavelength to be a good blocker.
From: Colin Stanners Sent: Thursday, July 07, 2016 3:09 PM To: [email protected] Subject: [AFMUG] RF blockage to make a ~350 degree omni (to prevent 450 interference to WiMAX) We'd like to put up a 3.65 omni, but have seen certain cases of interference between the 3.65 450 and PMP320 WIMAX, so need to "notch out" the direction of a WIMAX tower. There's no existing antenna or mounting structures to use as a shield, and at this site we need to be careful of windload. I'd prefer not to use regular pieces of metal that could reflect the signal and cause multipath. Is there some kind of outdoor-rated attenuating material?
