Cort, It sounds like a "mechanical" problem somewhere, as others have mentioned.
If you can get your hands on a TDR or similar device to sweep the new antenna and feedline on top (using calibrated 50 ohm load on the feedline, and then adding the antenna on for the next test), you'll probably find the problem. If you can't borrow that kind of gear, perhaps a jumper from the bottom feedline to the top antenna to see if it changes the performance would help you figure out if the problem is the new Telewave antenna, or the feedline going to it. Remember, the wattmeter at the transmitter will show "good SWR" if something is eating the RF but not radiating it. You may also want to consider sending someone up the tower with the wattmeter and seeing what's going on right at the input to the antenna, if all you have is the wattmeter for test gear. The key thing to remember is that the numbers should "match" theory, or be real close to it. If you're putting in X amount of power at the transmitter, and you know the feedline loss numbers, you can calculate for what you should see at the "base of the antenna" measurement. If the RF isn't getting there, you know it's a problem in the hardline. If it is getting there but you have high SWR at the antenna base, something is physically wrong with the new antenna, a connector, something... I think from this text and the replies of others, you can come up with a plan that will eliminate a section at a time... if you have jumpers inside the building to the outside, test those (a high power dummy load is nice here, if you have one that you know is a solid 50 ohm load, and not a hunk of junk that's reactive or cheap -- I like the big Bird dummy loads for this part of the "job"), test just beyond the Polyphaser (a friend had one show up bad from the factory lately), etc... all depending on how much "stuff" you have between the TX and the antenna... test at every point. Somewhere you'll find it all "falls apart" according to the numbers... or... if you don't, the antenna's got problems. At that point, jumper over to the other antenna with a nice solid piece of LMR-400 or better, and see if it behaves normally -- you'll find it! There's an art to finding this type of problem, but it's all based in feedline and antenna theory... if you know what the numbers SHOULD be at each test point, you're WAY ahead of the game. Make up a diagram and calculate feedline losses to each point, etc... it'll make it pretty obvious where the RF is "disappearing" if there's a mechanical/connection problem or a bad antenna. I'm no RF pro, but the pros I've learned from over the years would all tackle this problem this way... find the place where the theoretical RF behavior falls apart, and you've found the problem, most likely. It's better than just shotgunning in new gear until the problem is "fixed". Nate WY0X
