[TowerTalk] Antenna Swittch - Grounded or Open Unused Contacts

[ac9s at mchsi.com]

I am about to replace my 30 year old Ameritron antenna switch with a DX Engineering unit.  It will be placed at the top of the tower to select between the various antennas - wire slopers for 160 and 80, inverted vees for 75 and 40, and the Steppir ( currently under repair) for the rest of HF.  I will not have multiple antennas selected at the same time.  What is best - to wire the switch so that unused ports are normally grounded or open?  My inclination would be to ground all the unused antennas, but since the switch is shipped normally open I have an element of doubt.

Thanks --

Keith
AC9S