On Fri, 28 Sep 2007 20:16:30 -0400, Bill Freeman
wrote:

Anyone know what the purpose of an inline capacitor would be on a car
radio?

Hi Bill,

Probably for DC isolation (yes, what DC? is reasonable to ask, but it
is probably cheap insurance against an accidental short from antenna
to ground taking out the front end bias, or from static build up (but
a good choke to ground would solve that too)).

Another car antenna question, why do they use such a small diameter
wire inside the coax?

To reduce parallel capacitance to ground (line Z is rather immaterial
but its equivalent capacitance is not).

73's
Richard Clark, KB7QHC