The 1481 is twice as long as the 1480 and would have close to 3dB more gain. I have both Tram antennas but at different locations, so I have not tested them side by side. I do have other brand antennas I've tested here on a neighborhood repeater and have definitely noticed an increase in range going from an 8ft size dual band to a 17ft. I live in a hilly area and we get better distance to the horizon with the larger antenna but spottier coverage in canyons and valleys below the antenna.
Revisiting: I found a seller that's an hour away on eBay that has the Ultimate Support 110B, he's listed in Winchester, VA. I think he's my source for the tripod. Home Depot and the Tram. Now for a bit of convo...When does choosing the Tram 1480 vs 1481 make sense? In what circumstance would you choose one over the other? Gain is different for each, and if I'm correct, that would modify radiation patterns. I think higher gain means elongated radiation horizontally but shortened vertically. Am I on the right track?