Thanks again Tom, you've really cleared things up for me here.

Here's the concrete numbers... in the center of the band, S22 -- converted
back to an impedance -- is 119.5-j90 ohms. With a 2V source, if I conjugate
match my 50 ohm load obviously I get 1V across the resistor or 20mW = 13dBm.
Without a match... let's see... current around the loop is 2/(119.5-j90+50) =
9.2+j4.89 mA, and power in the 50 ohm load is I^2*R = 3.04+j4.5mW = (looking
just at real power) 4.83dBm. So... without a match... I'd be leaving 13-4.83
= 8.18dB of gain "on the floor"... ouch!

---Joel