[Repeater-Builder] Duplexers

[Mackey]

Our club was recently given a 220 repeater. We have two seperate antennas.  We 
do not have a duplexer. My question is do we have to have a duplexer? How can 
we keep the transmitter from desensitizing the receiver? The antennas are apart 
but can be moved farther.
Thanks
Chris
Kg4bek