Sunday, July 23, 2017

Torque Arms & Mount Corrected, 7/20/17

Thanks to the keen eye of David Robbins K1TTT, I now have my torque arm system properly installed and ready for service. Over the last 40+ years, I've climbed a lot of towers, mostly ham stuff with a little commercial work sprinkled in here and there. I've climbed towers with torque bars installed, but never gave them a second look as to how they were installed...as long as everything was solid and secure.

My dad recently gave me a torque arm assembly to install at the top of my Rohn 25 tower. He had it for some years, and never used it, so I was surprised when he pulled it from under a workbench up at the lake house. He handed it to me, and I said "heck yeah!". I had noticed my tower twisting a little in high winds and when the rotator would stop & lock, but no problems over the 23 years it was in service.

I was working on the top section for my tower, in the home workshop, so I  promptly got this thing bolted on and ready to go. It's an older version, and I couldn't find any info for it online. When I uploaded a few pics, it caught the eye of David Robbins K1TTT, who walked me through the proper installation. Here it is in a couple of pics, properly installed. They should already be above the horizontal braces, and the little "hump" in each are should allow clearance for the diagonal cross braces. Now, time to get this up on the tower and start stacking antennas!!





Dave WB4IUY
http://www.WB4IUY.net











Tuesday, July 18, 2017

More tower work, 7/18/17

Well, this is sorta tower work... I decided to get some of the bugs worked out of my top tower section, before hauling it all up to the 100' point. The previous blog described the issues with the thrust bearing, rotator shelf, and mast position. With all of that out of the way, I moved on to a setup and dry run prior to installation...

I installed the rotator and got it in position, slipped the mast into the thrust bearing, set the height of the mast, installed a mechanical stop on the mast so the thrust bearing would support the weight of the antennas (instead of the weight bearing down on the rotator), and installed a new set of torque arms  my dad gave me. I also have a new upper skirt my dad made, to shed the water from the thrust bearing, once installed. Here's a few pics...


Rotator connected to the controller, and a few test runs made to make sure it turns without any binding. All is well, and ready for action!
 

 Rotator alignment completed, with no issues in rotation. I can't wait to get this beast up on the tower!



Mast centered in the thrust bearing. The thrust bearing is now pumped full of fresh grease, and turning smoothly. Dad fabricated a new skirt for a water shed to install here...


 The mast sits about 1" off of the rotator housing, so as to not present any vertical load. 



 Dad gave me a set of torque arms he had stashed away for Rohn 25! Yes! This thing has always twisted when I would start or stop the rotation of the stack, this should solve that problem!


 Torque arms installed and ready for connection to the guy wires!



Can't wait to get this hoisted upon the tower to the top, and get my guy cables connected!!


Dave WB4IUY
http://www.WB4IUY.net











Sunday, July 9, 2017

More Tower Work, July 8 & 9...

Wow, this was a busy "tower work weekend". The temp were in the low 90's with high humidity, so we started early. First thing, I helped a friend take down his 48' Rohn 25 tower, in preparation for a move to his new home. Ken had already removed his antennas and dropped the guy cables (he had a Hazer on it!), so it came down fast. In less than 2 hours, it was laying on the ground and ready to haul away.


Before....



After, in under 2 hours!


I returned to my QTH and climbed to the top of the 90' section on my tower, relocating the gin pole from 80' to 90', in preparation for pulling up the next section. I've decided to put the top on it here, and stop the tower at 100'. There will be 15' of mast above that, with a 21' vertical antenna mounted on top of the mast...that'll put the tip top of my stuff at 136'. I'm already on a hilltop, located at 375' ASL, and the nearly identical setup has worked very well for me over the last 24 years. 

 Gin pole moved to 90' and extended to over 100', ready for the next section of tower...





I needed to do a bit of preparation and a few mods to the top section, to remedy problems I've had in the past. I cleaned the grease fitting on the thrust bearing and lubricated it well. It seemed to be dry, but then, it has been in the weather and in operation many years. The pinch bolts in the collar of the thrust bearing needed attention, as one had become loosened and fallen out somewhere along the years, shifting all of the vertical load directly onto the rotator. 

Thrust bearing on the top...new allen screws installed for centering the mast in the bearing...

Mast guide plate, mid-section...


Next, the lower rotator shelf has always been a problem, requiring the rotator to be left slightly loose on the shelf due to an alignment issue. It was pre-drilled when I got it (don't remember where it came from), and I found it was off about 1/4"! Whew... I marked the plate and slotted it with my old manual mill to allow for perfect alignment when it is reinstalled.

 Rotor shelf marked up to determine the error and corrections needed...


 Rotor shelf clamped down on the table of my old manual mill...


Slotting the rotor bolt holes to allow for accurate alignment of rotor, once installed in the tower...

The rotator is an old Alliance HD-73, and has served me well all these years. It's had a rough life, being operated severely overloaded for turning load, as well as having supported a tremendous amount of weight. Rotation, lock to lock, was generally on the order of 80 seconds. It was welded together once by a lightning strike, and I literally broke it loose with a hammer and never removed it for service...about 19 years ago!  Never-the-less, it has performed well. When the storm destroyed the tower back in April of 2016, it was stuck upside down in a tree for about a month, until we could get a crane to get it down. During that time it rained inside of the rotator, which certainly did it no good. I pulled it apart today, cleaned out all of the rust, wire brushed all of the moving parts and all 4 of the bearing races, cleaned and packed all of the 104 individual ball bearings, reassembled it, gave it a good cleaning and a coat of paint. A quick test found it working like new and ready for action. 

I had to use the Dremel tool and a cut-off disk to deepen the slots of the screw heads, so they could be removed from the terminal strip where the rotor cable connects. Lots of rust...


 Loads of rust on the terminal strip...


Corrosion on the bottom of the housing was so bad, it looked as if the bottom of the rotor has been hammered in... I cleaned it off with a wire brush, and it got a heavy coat of paint later... 


Terminal strip cleaned with a small sanding wheel...


New screws installed in the terminal strip...



Rotor, after disassembly, internal cleaning and lubrication, and re-assembly...


I gave it a "road test", a fresh coat of paint, and she's ready for action!


That was all I could do today, and tomorrow is another work day. More work coming soon, the tower top will be headed up to the 100' point in a few days!

Dave WB4IUY
http://www.WB4IUY.net










Thursday, July 6, 2017

Stacking the 90' Section, 7/4/17

The tower work is moving right along, it won't be long before I get the antennas re-installed. I had a little time on the afternoon of July 4th, and decided to get the next section pulled up and installed. I loaded up the tool bucket, and pulled it up to the 80' point with the gin pole. I climbed up to 80', attached the tool bucket to the tower, climbed back down to the to the 70' point, dismounted the gin pole, climbed back up to 80', pulled the gin pole up, and reattached it to the top of the 80' section. Once attached, I pushed the center of the gin pole up 12' (to about 92'), dropped the rope down to the ground, and climbed back down. 

Once on the ground, the 90' tower section was tied to the rope, and hoisted up to about 92' and tied the pull rope off at the base of the tower to hold things in place until i could get back to the top. Back up the tower I went, up to the 80' point, and tied myself off to the tower. The 90' section was pulled around, Debbie loosened the rope at the bottom of the tower, and we lowered the 90' section down and onto the tower. 

The 5/16" & 1/4" bolts were installed in each tower leg, and I called it quits for the evening. Below is a short video Debbie took with her phone while zoomed in, along with some pics she and I took with our phones while doing the work. 


A little video of me climbing up to the top of the 80' section, getting ready to attach the 90' section of tower...


 Heading up the tower, this was at about 55' up...


 You can see the gin pole above me, holding the 90' section...


 Debbie was taking these pics from the drive out front of our home, with her cam zoomed in...


 Heading on up, almost at 70' in this pic...


 Securing my safety belt to the top of the 80' section...

 
 Installing bolts in the legs of the tower section...


 Taking a photo of Debbie...w-a-y down there, on the back deck below me. 


 Looking at an incoming storm on the horizon, about 10 miles away, as seen from about 80' up. 


 Looking up the tower to the top of the 90' section.


 Looking down the tower from my perch at 80'...

 
 Finishing up and heading back down...


 Up to 90' in this photo...a thing of beauty to me :-)


 My tower is pretty well masked from view by all of the trees on our property...


 ...as seen from my back yard...




Dave WB4IUY
http://www.WB4IUY.net