and isolation of different channels
through one antenna
There are many applications
in which you may wish to use more than one channel
for communication, but do not wish to have multiple
antennae. Perhaps there might be a space restriction
(such as on a motorcycle or small craft), or you
do not wish to draw attention to a “forest” of different
antennae (maybe on a car being used for covert surveillance).
With Wallen Mobile Filters, it would be possible
to use a single antenna (matching the original vehicle
design) on an unmarked Police vehicle handling communications
that use different channels. This could allow the
occupants to combine GSM cellular access with the
Police radio band, and still tune in to their favourite
radio station, meanwhile!