Tuning 70cm duplexers, what -dBm

[hostile]

What is a decent dBm attenuation to shoot for on the filtered and passed signal ?
Right now I am at -90dBm and -0.8dBm
repeater would be on same antenna and operate 100-200' with 100W.  Not sure receiver sensitivity yet.

[thinkfat]

That depends on the output power and the noise floor of the receiver, how well it suppresses close-by signals and the maximum no-damage input power. But typically, you'd want more than 100dB between the TX and RX path.

[N0NB]

Here I have a TX RX Systems 28-70-02 that is spec'ed at 100 dB isolation per channel and 0.6 dB if insertion loss.  I measured 0.6 dB on one side and 0.7 dB on the other and approximately 90 dB notch depth.  The receiver has a measured SINAD of -118 dBm and the transmitter is set for 25 Watts with the antenna at about 190 feet, Height Above Average Terrain of 156 feet.  The repeater is a Kenwood TKR-850 V1.

Range is about 30 miles and after a year I have not noticed any desense and is rather well balanced.