IIRC, all transponders have their own built in GPS receivers
. They may or may not require an external antenna
, depending on where they are installed and on the demands of the specific unit. Splitting will not work
for the gps portion. However, splitters can work
well for the VHF
tx/rx part. The best ones, like the Vesper unit, have built in preamps which compensate for any insertion losses. We are using a Vesper and with our masthead standard VHF antenna
get excellent range of reception
(typically 40+ miles with normal conditions) and have had reports of being received at as much as 15 miles.