I worked on a project a while back which used a Linx Technologies module with several hacked keyfobs. The keyfobs will transmit as soon as they receive power. The module has several relays which then trigger other devices. When I'm testing the modules outside of their cases, they appear to work fine but when the cases are closed it seems like the signal is flakey as the relays start clicking on and off. The transmitters are 433mhz keyfobs and they are encased in a box made of 1/2" thick high density polyethylene.

Does anyone know if this material would be blocking the UHF signal from transmitting?

Thanks

 

Plastics dont normally resist RF, just metals.

 

RF goes through plastic like a hot knife through butter. For a given power level there will be maximum distance at which the key fobs will stop operating reliably.