If you can't swing a longer yagi, you might investigate stacking some horizontal omnis with gain. A moonbouncer friend of mine uses such an array as one of his spotting antennas. I believe he has 6 'Big Wheels' stacked on the top of quite a substantial tower, and he claims about 10 dB omni gain from them. I've always wondered what a 4-bay array of short yagis would get you. http://www.youtube.com/watch?v=POyXfy-qxAw and http://www.youtube.com/watch?v=ffAH93QPrFk W0VB is a local here in Rochester, MN - he was the first ham to make WAS on 220 MHz., and he's done WAS on 2 meters twice. The antennas you see in the video did not survive the next big ice storm, however. I don't know what he's got up now.
As for the preamps, I ran a mast mounted preamp ahead of a fairly long run of Belden 9913 and an FT-726 that was a bit hard of hearing on 2. It helped when working Oscar 10, mostly because the antennas were pointed up into the quiet sky, rather than horizontally at the noisy Earth. I always wanted a way to adjust the gain of the preamp remotely, and the unit I had didn't have that provision - I never got around to trying to vary the voltage to the unit - I'm not sure that would work because the unit used the supplied 13 volts for T/R switching, too. With the gain set the way it came out of the box, it was simply too much. In-shack preamps did nothing to help that I could detect.
I wouldn't think you'd need much more than you have to work up and down the Front Range pretty reliably. I've worked Cheyenne from a mobile rig on a rise near Boulder, on .52 FM - no problem. The changes you're considering would be good for meteor scatter and the rare auroral opening in Colorado, though. Your existing setup should be good for some meteor work. Random meteors happen all the time, and you can make random meteor contacts or set up schedules. WSJT software makes it much easier. Another local here in town has used WSJT to make meteor contacts with a small yagi in his garage.
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