Bests & Worsts Reviews from Amazon

I'm a retired engineer in a group that's experimenting with mesh networking. I bought two of these, each from a different vendor. One is Bolo Brands and the other is Super High Power. My antennas both work but the gain is nowhere near 18 dBi. My antennas are identical in their poor performance and identical in packaging, labeling, appearance and construction, right down to some scribe marks where the feed is attached to the boom. Something is not right with the design because the gain only seems to be about 10 dB. The "stock" router antennas -- the six-inch plastic rods that screw directly onto the routers -- give a certain signal strength as I measured it with special software. These are widely advertised as having 7 dBi gain (not verified by me). Unfortunately, the Bolo Brands antenna only does 3 dB better. The assembled antenna only works about 5 dB better than just its loop feed, alone, which I unscrewed and removed from the boom for testing. For an assembled antenna with a true 18 dB gain, the difference should have been huge -- 14 or 15 dB -- but it wasn't. I'm missing almost 10 dB. I repeated my measurements many times, to eliminate any chances of random errors creeping in. A decent antenna, the Enterasys RoamAbout, is rated as delivering 14 dB of gain and it ALWAYS outperformed this disappointing so-called "18 dBi gain antenna." I will be posting a matching review for each of my two new antennas.