tsk, you seem to have good understanding of antenna theory... so, more questions...
- the folded dipole antenna that you suggested is directional, right? then it should NOT be suitable for mobile application? Even for home use, it depends upon locations of various stations (you may need to change the direction when you change stations).
Based on whatever I know, I do have some idea as to what might be a better antenna- Vertical, long antenna, minimum of about 5ft for FM (essentially translates to external motorized one) because all others are shorter than the minimum requirement. Also, it is desirable to have a plain horizontal conducting surface just below the vertical dipole as it creates a mirror image and virtually doubles the effective length. I think mounting at the center of the roof would be ideal
, but all of them are mounted on the boot. However, I am not really an expert, so wanted to check with people who might understand theoretical or practical, or even better- both aspects in depth.
Do you agree that all shorter varieties should be inferior to motorized vertical dipole?
What about rabbit ear glass antenna... these too?
Backward tilting makes sense to reduce permanent damage due to bending by air resistance. but does it have any disadvantages (or advantages) in terms of reception? do we have to increase the length to compensate for tilting?
Major issues in reception are-
1. picking up weak, long distance stations
2. being insensitive to reflections in cities
Are these different antennae particularly suitable or unsuitable for dealing with above mentioned problems?
Does polarization matter for FM radio?
Sorry, I have made it too technical, but I am sure answers to these questions will be quite useful (practically!) to all of us.