Tuesday, September 20, 2016

Tear Down and Review

As the closing date for my house came ever closer I could no longer delay removal of my antennas and towers. About 3 weeks before the deadline the first antenna came down. I then proceeded in stages until all was down, packed and their imprint removed from the lawn and house. My objective was to leave only footsteps behind, and that is just what I accomplished.

There was no need to simply pull the big switch and go QRT immediately. I planned the removal process so that I would be on the air for as long as possible, even if with lesser capability. My reasons were to remain active, since I enjoy being on the air, and to work a few of the current crop of DXpeditions. There will of course be other DXpeditions to these same countries but why wait if it isn't strictly necessary.

The order in which antennas and supports came down was dictated by operating priorities and dependencies; for example, the yagi must come down before the tower (obvious, I hope). As always I also try to learn something from what I built so that I can do better in future. That's the real purpose of this article.

80 meters

This 80 meter tower vertical was the easiest antenna to remove since all the components but one were at ground level. The radials were difficult to locate since the sod effectively covered and hid them in just one year. I rolled up the radials, cut them at the tower end and then removed the L-network box. Apart from the one previously severed radial everything was in good condition. The coax connector was pristine inside once the weatherproofing was removed.

The 3" galvanized framing nails that pinned the radial ends to the soil had substantial surface rust. The lifetime of buried galvanized steel has a varies with climate and soil chemistry. It can last less than a year or for a generation or more. The acidic soil around here is clearly unfriendly at least to the light galvanizing on these nails. But then they are designed for framing not burial.

With the antenna removed I cut the coax from the overhead cable bundle. This was easy since it was the last installed and therefore the other cables remained as a bundle when the tape and tie wraps were removed. The freed coax was pulled out of the shack and carefully rolled up. It is now ready for its next adventure. The L-network may be reused in a different configuration for a future antenna. I save everything.

Later when I was stripping the tower I removed the "insurance" jumper between the mast and tower. There was significant corrosion. The combination of three different metals -- galvanized steel, copper and stainless steel -- made for some interesting chemistry. I expected something like this but didn't worry about it since I knew the antenna would likely be up only one year. For a permanent installation attention must be paid to dissimilar metal corrosion.

Tower cabling

Removing the cabling was a one climb process. I planned it that way. Here's how I did it.
  • Carry a rope up the tower.
  • Starting from the bottom cut the tape and tie wraps securing the cable bundle to the tower.
  • Stop near the top. Wrap the rope around the cable bundle in a coil about 4 to 6" (10 to 15 cm) long. While tempting the rope coil should not butt up against any connectors. This length of wrapping prevents kinks and pinches. Temporary tie the rope higher on the tower, being sure the rope is reasonably taut between the tie off and the cable bundle.
  • Disconnect the coax runs from the antennas, cutting or removing the weatherproofing as needed. Inspect the connectors to confirm there has been no water damage (there wasn't). Do the same for the rotator cable. I use connectors so that the terminal strip on the bottom of the Ham-M rotator does not need to be accessed and should in any case have been coated in a protective goop of some kind. The connector allows the rotator can be removed later, not now when it is holding a mast and yagis.
  • Cut the remaining tape and ties on the cables. The rope will now take the weight of the cables. Unless your tower is extremely tall the cables are perfectly capable of supporting their own weight.
  • Untie the rope and lower the cables to the ground. Take care that they don't tangle in the tower and guys.
  • Climb down and roll everything up
The only problem I discovered was that the bracket with an SO239 I had made up for the Explorer 14 feed point slipped out of the tie wraps holding it to insulating block and boom. I need to come up with a better bracket. Note that I do not use the BN86 voltage balun that comes with the antenna. Instead I used a coax coil as a common mode (current) choke.

Before climbing I had untied one end of the 40 meter inverted vee so that it could be lifted over the guy wires; I needed both legs to be dangling on the same side of the tower to avoid snagging the guys when lowered. The vee was untied and without a care was dropped to the ground, including feed point and coax coil choke. It survived the 14 meter fall just fine, as I expected. Any damage would have been easy to repair and I didn't want to deal with a second rope for this antenna, or have to do an additional climb.

The aluminum tube and clamps that support the vee and off set it from the tower were removed and also dropped to the ground.


The Explorer 14 yagi was the only step in the dismantling process that caused me grief. What I expected to be a one hour job took 3 times as long. This is one more time that gravity was not my friend.

I installed the same rigging I used for raising the yagi. This time I discovered that the slightest snag on a tree limb, guy or even the rope tram caused major midair hangups. The Explorer 14 has lots of plates and clamps that will easily snag. Gravity makes it worse due to the yagi's weight (45 lb or 20 kg).

Since the rope truss holding the boom is designed to rotate (to make it easier to manually orient the yagi as each step of ascent and descent) these multiple snag events would rotate the yagi and make the problem worse. Tree snagging was particularly bad since they had grown over the intervening two years.

In the end I could not get the antenna to ground in one piece, or at least not before sunset. The alternative was to remove elements or pieces of element when I could reach them from the ground or on a step ladder. With many contortions and tower climbs, I eventually got it all down.

As I disassembled the antenna I grouped together the pieces for each element and for the boom. I only endeavoured for lengths that would reduce reassembly time yet make the package short enough to transport by small vehicle. I taped together the pieces of each element to, again, ease reassembly and then wrapped the entire package with duct tape. I was able to keep the 10 meter coupled resonator assembly mostly assembled, which was a boon.

Rotator and mast

With the yagi down I removed the pulley that I had temporarily attached to the mast. The schedule 40 pipe mast was dropped to the ground after loosening the bearing and rotator hardware. Although the hardware seemed to be gripping the mast quite well sometime this past winter a wind storm caused slippage. The 15° direction error was just enough to be annoying. Rather than climb the tower to fix it I mentally calculated the antenna heading. I knew it would soon be coming down.

Another problem that appeared in the past year was that the rotator did not turn the antenna smoothly. There were heading where rotation would slightly slow. I assumed this was due to the old worn bearing I had refurbished. Yet when I had it all down on the ground the bearing was fine. I can only assume trouble with my ancient Ham M. I will disassemble and service the rotator before it goes up again.

DMX tower

I considered removing the upper sections of the tower without a gin pole. I've done this before. The trick is to lift the unbolted section and smoothly rotate it while lowering it to chest level. When done properly the section doesn't spin out of control and smash against you or the tower. It instead comes to a soft landing across one side of my body and harness.

In the end I decided to resurrect the gin pole I built for raising the tower since I didn't deem the risk worth the time saved. Luckily I had all the parts in storage and was able to ready it in less than an hour.

Unlike the raising I handled the rope while up the tower. Once the gin pole was secured to the section below and the roped attached I removed the splice bolts. With one hand on the rope and one on the loose section I would lift it out of the tower, push it to one side and lower it to the ground. This worked so well I may try this when next raising this tower, if it is again a one man job.

Before removing the top section I disconnected the guy wires at the anchor. I then climbed the tower just once to disconnect the guys from the top guy station and remove the top section. The guys were thrown to the ground. They survived the fall just fine, as I expected, even the ceramic insulators. They're tough.

Before removing the lower guys I attached temporary rope guys to the top of the second section (DMX5). Guy removal was done the same as for the top guys.

With just the lower two sections remaining I removed the bolts holding the legs brackets to the floating platform and then the ropes. By hand I tilted over the remaining 16' of tower in the reverse of how I put them up. However this time it was more difficult. I expected and planned for this. That's why I wore a hard hat and boots.

The sudden increase of weight on my outstretched arms made a safe controlled descent difficult . When I reached that point I moved out from under the tower and only endeavoured to slow, not stop its fall. This was easier and safer than the alternative and the slow speed impact with the sod caused no damage.

The sections were stacked on the deck as shown in an earlier article. All the tower hardware went into a large plastic container. I now have a nice and neat package ready to be carried to the new QTH.

Inverted vee & Golden Nugget tower

The last to go was the first antenna: the multi-band inverted vee. Since it is an easy one to remove I left it up to the last minute so that I could keep operating. When the DMX came down I moved the leg anchored from the tower to a fence post. The impedance changed on most bands but was still perfectly usable. Unfortunately this wasn't enough antenna to work the A5 DXpedition on a difficult polar path under poor propagation. With nothing else of immediate interest it was time to permanently shut down operation from this QTH.

The toughness of the antenna continues to impress as I lowered it and bundled it up for storage and transport. The lighter colours of THHN stranded copper wire I used showed some fading due to UV damage. The black insulation appears to have fared better. There were no other visible issues. All the connections were free of moisture and the spreaders didn't slip. This may become the first antenna at the new QTH, just to get on the air with something before the towers can be raised.

I opted for "speedy" dispatching of the house bracketed tower, at some small risk to the tower itself. After removing the two 10' (3 m) sections of mast projecting out the top of the tower (again, thrown to the ground without damage) I set up ladders and proceeded to disconnect the brackets. This is a light tower (75 lb or 35 kg) so a strong bungee cord holding it to the eaves trough easily held it vertical.

With the bracket removed (and thrown to the ground) I wired the bottom of the tower to two temporary wooden stakes so that the tower wouldn't kick back and damage the house siding. Back on the roof I tied a long rope at the 25' level, then removed the bungee cord and gave the tower a nudge in the direction I wanted it to fall. Unfortunately the tower had a different idea. I pulled it back when it headed towards the deck. This action caused the tower to swing and put a dent in the aluminum eaves trough.

My second attempt was more successful. This goes to show why side stays are strongly recommended for this type of operation, which is equivalent to a reverse of the falling derrick method of erecting light duty masts and towers. I thought of doing that except for the fact there were no suitable places where I could the ropes could be anchored.

When the tension on the rope grew large as the tower passed the point of no return I let the rope play out with only the friction of leather gloves to slow its descent. (Please note that this is dangerous! The tower can easily pull you off the roof if you foolishly believe you can manhandle or withstand the force of a leaning tower. Leave the job to gravity. Towers are cheaper than your life.) With a light thump on the ground it was done. There was no damage. The sections easily came apart since I had greased the bolts and was careful not to over-tighten the bolts during construction.


The wood platforms for the two towers were pulled out of the ground. For now I've kept them intact in case I decide to use them again. I might instead use materials that will last 20 years rather than the 5 to 10 years the preserved wood can be expected to survive in this application.

September is an ideal time of year to plant grass seed. I found enough organic material and soil to fill the holes in the ground, which I then raked and planted seed. As I write this article the new grass is sprouting nicely. In another two weeks it'll look very good indeed. The reseeded area is more than just the platform areas since all the work damaged more of the lawn closer to the house where the cables terminated and the house guy anchor was located.

The holes in the house walls left by the removed brackets for the Golden Nugget tower were filled. They are now ready for staining so that those areas match the surrounding cedar siding. The dented eaves trough from the botched lowering of the tower was repaired enough to make for an acceptable appearance.

Since I didn't have a milled board long enough to replace the one where the pipe pierced the house wall I used a round plug from a scrap board left over from the original construction. I made it a snug fit and sanded the area to remove ridges. I had asked the buyers of the house if this was acceptable and they approved. The hole through the house was filled with expanding foam, then the vapour barrier was stapled back in place, restoring its original condition.

As I stated in the earlier article my intention is to leave only footprints. Very soon the signs of a ham station will have been completely erased.

Lessons learned

Despite a few glitches, in general towers and antennas come down easier than they go up. There is nothing to measure, buy, build or test, all of this having been done during erection. However this can be deceptive in that we can inadvertently stray into danger. Respect gravity: it's stronger than you are.

I've gotten better at weatherproofing connections. There was no evidence of water incursion or corrosion inside any coax or cable splices and terminations.

Greasing of the tower nuts and bolts worked out quite well, as it should. Once the hold of the lock washers was broken with wrenches the nuts on all bolts spun off without resistance. There was little evidence of new rust.

Stainless steel hardware is typically not high strength! It doesn't rust but can be easily damaged with excess torque or omitting lubrication to prevent galling. I could have done better when I rebuilt the Explorer 14. I was in a rush at the time so I explicitly chose to take the risk. Some of the stainless steel hardware will need to be replace. I recommend taking the time to do it right.

Last minute reprieve

I could have waited had I only known. As a result of some frantic and difficult last minute negotiations among all the parties, and with one of my banks, the closing was delayed a few weeks. No matter. The tear down of the station had to be done and now I have an additional incentive to get cracking on the new station.

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