On 21 May 2006 14:17:19 -0700, "an old friend"
wrote:

haing gotten many of the peices of a 222 band repater and wanting to
put it on the air how much sepertion is required to avoid a paying the
price of a duplexer at 22 band

any assiatnce welcome

Depending on the transmitter and receiver type, good ones will require
around 75 to 85 db of isolation at least.

30 feet of vertical seperation of antennas will give around 60 db of
isolation.
60 feet of vertical isolation may give around 70 db of isolation.
After that it starts to flatten out.

600 feet of horizontal seperation will give around 60 db of isolation.
It will take doubling the distance for an additional each 6 db of
isolation

73
Gary K4FMX