[amsat-bb] Question about duplexer as a high-pass filter

[skristof at etczone.com]

My satellite rig is two HTs running to an Arrow antenna. Trying my best
to operate full duplex. When operating V/U I am using the UHF side of
the Arrow duplexer as a high pass filter between the UHF antenna feed
point and the UHF HT to keep the 2 m transmit signal from desensing the
UHF receive. 

But it only sort of works. 

This set up leaves the VHF end of the duplexer open and just hanging.
Would this setup work better with a 50 ohm load across that empty
connection? (Sorry if this is a dumb or elementary question, but I'll
never find out if I don't ask.) 

All helpful insights are welcome. 

Steve AI9IN