I have a 30 foot Rohn 25 tower with the 25AG2 "rocket top" that has been up for about 10 years now. I'm using a HyGain Ham IV rotor mounted to the standard Rohn rotor mounting plate "inside" the tower. I have a 5 foot mast (2 inch) from the rotor to my tri-band boom. The tower uses a Rohn house bracket about 15 feet up from the bottom, just under the eaves. Almost from the very beginning the mast "groans" when turning through a particular range of azimuth. I fully understand why it is doing this...it's slightly off-center and when it hits that area of rotation it is just rubbing hard. On a couple of occasions I have sprayed some WD-40 or garage door opener lithium grease down into the mast bracket pipe and it sounds great for a short while...then of course it's right back to "groaning" a week or so later. Once when I had the beam down from the tower I took a close look at the arrangement thinking that this would be the time to try something. I shifted the rotor around by 1/3 (3 mounting holes at 120 degrees) but it really didn't seem to make much difference. I suspect that this will never improve unless there is some way to "seal" the bottom end of the 25AG2 mast pipe and lube it very well so that the grease cannot leak out. That's obviously easier said than done! Anybody faced this before? Any ideas? It's very annoying and I really cannot use the rotor after the XYL goes to bed...it's just too noisy.