Back in a post on July 4, 2011 with subject Disaster!
(Page 105) I relayed my antenna troubles. (Delhi VU-936SR snapped in two in November 2010. UHF section was dangling on twin lead going to the preamp until I climbed up the tower in the 20s to cut it loose and lower it down. Other than the break it was undamaged. Lowered the VHF section the following July and put up my old Radio Shack U-120 as a stop gap measure.)
Here is an update.
I managed to find some one inch inside dimension 1/8 inch thick aluminum square tubing at Rochester Welding up on US 63.
After trimming off the torn end of the UHF section I proceeded to slide it on. Took some convincing from Mr. Sledgehammer, but almost got it fully on. About an inch short of the first insulator.
The original thought was to join the antenna sections again to repair it. But ran into an impasse. The bolt joining the two VHF sections was rusted and could not get the nut off. While I was battling that, the VHF end turned into more of a problem. The antenna broke right at the brace joining the top and bottom booms. Would have to drill out the rivets, then figure out how to reattach the brace to different sized booms.
In the interim, based on the VHF reception from the RS U-120 on the top of the tower, decided to see what I would get with what I had. Drilled two holes for a U-bolt in the new tube and mounted the antenna on the ten foot tripod and aimed it north. I did manage to pull in 9 and 11. Hmmm.
I had a bad feeling another session with Mr. Sledgehammer trying to join the UHF and VHF sections was not going to work well. As the non-sledgehammer end of the UHF section was slightly crinkled. Had to saw the end off before reconnecting the UHF Power Zoom section.
Thus decided to go with just the UHF section.
Mast was 1 1/4 ID ~1/8 thick galvanized pipe on sale from Menards. Yes I know it is not a mast, but the masts I took down were bent from the wind. This pipe is thick and heavy. Cut to six foot length.
Could not track down the Delhi BBMB bearing, so went with Yaesu GS-065. Unfortunately its hole spacing is 60mm while the tower plate hole spacing is 3 inches. I wasn't about to haul up a drill 70 feet. Used a piece of pressure treated 2x8 instead. Drilled holes up to the bearing, then installed t-nuts to attach to the tower.
Gave up on the two bearing setup as my feet in clodhoppers would not fit in the tower with the mast in the center. The rotor would go on the bottom plate. But I had no rotor bracket. Settled on galvanized deck angles to bolt to the rotor and then to the tower. Fortunately I took lots of measurements on previous climbs to know where to drill the holes.
Installed the mast up from the bottom instead of trying to drop it in from the top. It is heavy enough I wasn't sure I would be able to handle it at odd angles. Plus it was at the end of my reach when standing on the level foot strut making it even more difficult.
The bearing comes with inserts to go between the bolts and the pipe to spread out the contact area. How on earth is one supposed to putz around with those 70 feet up without dropping all of them? Drilled tiny holes in the horizontal part, then strung stainless wire through the holes to wrap around the top bolt of the bearing to keep them in place until tightened down.
Installed the rotor. Measurements were accurate, everything fit. Made enough slack to allow the rotor to move back and forth and sideways to line up with the bearing. Which keeps the weight off the rotor.
Installed the antenna. Beforehand attached some aluminum angles to add additional bracing for the single u-bolt.
Stainless steel hardware throughout. I hate battling rusted nuts 70 feet up.
Then tried to center the pipe in the bearing. Even with wooden shims of the right thickness, that is a pain. I thought I had it close, but the rotor stopped working so I swapped it out. Having it inside the tower makes it much easier. Another attempt to center the mast. This time it worked better. But I need to research better centering techniques.
In a nutshell got everything I got before. 8, 9, 10, 11, even 12 KEYC was coming in at times. Can pick up high VHF with this setup. (At the time the new WEAU tower was not finished.)
Then it got colder and the rotor stopped working again. Tried the rotor I brought down, and it was still working. Decided to put the spare bearing on the deck overnight. Discovered they didn't use synthetic grease!!! Stiff as a board. For crying out loud. So on warmer days coaxed the antenna to La Crosse to get 25 and 19 for Packers stuff (that is, until that total fiasco on Sunday). A bit off axis for 8 so it is breaking up more. And Iowa 24 is at a bad angle, it has trouble coming in.
Put the U-120 on the tripod on the ground and aimed it north, using the rotor I brought down. Get the Cities stations that way. Menards had sales on the RCA antennas. Evaluated the biggest one (ANT3038XR) in case the UHF remnant on the tower broke apart. Its UHF performance was worse than the U-120 so discontinued using it.
Will need to investigate synthetic grease, soon, in time for below zero tests.
Attachment shows the UHF remnant with the UHF Power Zoom, the additional bracing, the bearing, the 2x8 below it and the rotor inside the tower.
Over 20 hours of tower time to finally get to this point. And more to come when it is time to swap bearings. Ugh.
0 signal strength on the new 38 WEAU, so way off axis on it. I never had a problem with their transitional UHF before they went digital on 13. So with the Packers one and done, I risked losing 19 and tried to move the antenna while the temperature was around freezing. It took a bit of coaxing back and forth, but I finally got it to move enough to pick up WEAU. Hooray! Basically 40s for signal strength on the DigitalStream converter. 19 as expected is now spotty, but rest of La Crosse is fine (but weaker) plus all the locals (24 off the back is better now).
This two antenna setup will get me through the winter, barring complications.
I am now thinking when the time comes is to get the biggest UHF yagi I can find. Based on my previous two UHF yagis, I still should be able to pick up VHF high.