Best type of aerial for a radio?
 

"Doki" wrote in message
...

Ian Bell wrote in message
...

Your aerial is too long. The wavelength of 102MHz is about 3 metres and
your aerial is a quarter wave whip, so it should be about 75cms or 30
ins
long in total. Assuming there's about 6 inches inside the radio then
your
add on bit should be no longer than about 2 feet.

I've got one of those big "T" aerials wired up to my Arcam tuner, it must
be
about 6 feet long in total. I presume it works on a different principle as
subjectively reception seems very good on R3, but then the only other
radio
I listen to is in the car. Hows that work?



On the first paragraph above: the length of the aerial only matters if it is
impedence matched. As most portable radios have a relatively high impedence
input the length of the aerial is largely immaterial - basically the longer
(within reason) the better, although it will have some directionality if it
is anything other than vertical.

As for the 'T' aerial - what you have is probably a half wave dipole, which
for a wavelength of a little more than 3m you would expect to be of the
order of 1.5m or 5ft long.

You don't say if it is vertical or horizontal? If the latter then you would
do well to change it to vertical as when horizontal it is somewhat
directional, whereas vertical it is near omnidirectional. With very few
exceptions all VHF transmitters in the UK now use mixed polarisation for the
benefit of car radios - that is the signal contains both vertical and
horizontal components (actually achieved by placing the transmitter antenna
at 45 deg!)


--
Woody