Review on Biynpbe Straight 433Mhz Rubber Antenna by Chase Steele

Like many of these cheap antennas they have a free space resonance at 473MHz. I installed it on the side of a metal box and its resonance dropped to 440MHz. So if you use the bottom layer you might get some boost at 433, the advertised frequency. If you are using a plastic case you can also use a straight piece of wire as they have no gain at all but some loss. If you are using a metal box, remember that the main lobe is offset from the box. This means that the antenna is directed away from the box with maximum signal.