I need to construct a good TX antenna to operate on the 70cm (433 MHz) band...
The special case here is that it will be fed by a +10dBm TX circuit and both the circuit and the antenna will be mounted under a car. This posses a unique problem since the underside of a car is metallic. I'm not expecting to get lots of gain, I just want a efficient antenna preferably made out of solid conductor wire. I will probably use a dipole design, but am definitly open to suggestions. Another concern is placement of the antenna, and my RX will have vertical polarization (so I can't see a way to prevent cross-polarization). Will the RF that is directed toward the ventral of the car be reflected back down at this frequency? Then what will happen? Should I mount nearer to the posterior of the vehicle or in the middle? Any suggestions?
Thanks!