I have a few related queries, hopefully it doesn't sound off-topic:
What kind of antenna is the best from signal reception point of view? Here is a list of various types we see around-
1. glass antenna

2. small roof-tops (GM, skoda I guess)
3. long roof-tops leaning backward (NHC, swift, ikon)
4. manual extendable attached to A-pillar on driver's side (most marutis, santro)
5. huge, motorized, extending above boot in sedans. A few high end cars have it tilted backward; what purpose doest it serve?