Ahaha! I love the "Sandlot" analogy. Great movie. And I will grant that I share Small's profound ignorance. To continue the Sandlot analogy, I hope that despite my ignorance that the team rallies and helps me learn what I need to know.
I have been looking into the SINAD method of testing receiver sensitivity. I see that Comtekk has some software for measuring SINAD
http://comtekk.us/sinad.htm. Has anybody used this or have an opinoin if it is wirth the $39? My SSG can do the 440 range but on harmonics and is a little touchy to get set. I use my RSP2 SDR as a frequency counter. I know that may seem pretty cheesy but I nailed the last ARRL frequency contest within a couple hertz using it a while back. Buying a proper counter is on the agenda but not in the immediate future.
Thanks for the detailed write up on how to do desense test properly. I will be acquiring the equipment needed but it won't be overnight. I have ordered some RG400, it will be here soon. I also do have a directional couple that I got from mini-circuits. While I do have a nice step attenuator I have been cautioned that it should not see the 5 watts out of the repeater. I will have to get a more power capable attenuator. I think I may have a 12 or 24dB unit in the junk stash, I'll dig. I am trying to find a way to do some work with what I have and then improve as I can.
I see why the SINAD method is best for testing actual measured receiver sensitivity. However, I am not too concerned in this case of getting accurate numbers as I am being able to determine at least roughly how much desense the system is experiencing and if I am making improvements. In that case, is there any real problem using the signal generator to use the break in squelch level as the baseline and then use the break in squelch while transmitting to determine how much desense is being experienced? I think I have most of the equipment to do this as detailed here:
http://www.repeater-builder.com/antenna/desense-testing/desense-testing.htmlFinally, and I know Smalls (ME!) will be killing you, why would having only the center conductor connected appear to improve the sensitivity? Type slowly and use small words.

NA4IT, good link. Much useful information on the RepeaterBuilder site.
Many thanks for all of the help.