Monthly Archives: March 2013

Tower Install – Day 8 “Finishing Up”

I completed most of the outdoor work on Saturday night and all that was left for Sunday was to get the coax and control cables into the shack. In the past, I’ve drilled individual holes in the outer wall for each cable, but this time I drilled a 2″ hole to accommodate a 2″ piece of conduit. That should suffice for my requirements for the foreseeable future without any need for additional drilling.

Drilling the hole with a hole saw was easy, but the hole was slightly too small for the conduit, so I spent the next hour with a rat-tail file enlarging the hole while cursing the salesman at Home Depot who told me that I didn’t need a small drum sander attachment for my drill. After installing the conduit in the hole and caulking the outside joint, I cemented a 90 degree section on the outside with the bend directed toward the ground to keep rain water out (during storms, rainwater hits our house horizontally at times).

Next I cut a piece of coax to size and installed two UHF connectors and shoved one end through the wall and connected it to the Alpha Delta surge protector attached to the ground rod right outside the shack. After waterproofing the connectors with 3M Temflex 2155 ($2.48 for 22 feet at Home Depot as opposed to CoaxWrap at $5.99 for 10 feet at ham stores) and Scotch 33+ tape, I moved on to the rotator cable. Rather than connect the cable coming from the tower directly to the 4-pin connector that plugs into the controller, I used a barrier strip to join the two lines to give me the flexibility to swap the lines around as needed (e.g. if the antenna turns clockwise when I command it to turn anticlockwise).

After some cleanup, I unpacked all of the gear that had been in storage, arranged it on the operating desk, connected all of the cables, and was good to go. After verifying that the antenna turned in the expected direction, I fired up the rig. At first, I listened on 20M with the vertical I had been using previously, just to have some baseline of comparison. I could tell that 20M was open, but I wasn’t hearing too many stations and many of those were just above the noise.

Switching to the TH-7DX was like the difference between night and day. I was now hearing dozens of stations up and down the band and many of them were S9+20. Wow! I was too tired and hungry to spend much time at the radio, but I did work two new countries, one of which was in the middle east, a region I never heard on the vertical in almost two years of operating from this location.

I took a quick rest and dinner break and was back at the rig where the band was still hopping. On the vertical, 20M always closed about an hour after sunset. On the new antenna, it was still going strong at 11:00 pm, over four hours after sunset. I suspect that it’ll probably open a few hours earlier in the mornings too.

No pictures today — I’ll take some of the various pieces later and update this entry.

That’s all for now — I’m off to work Spratly.

Tower Install – Day 7 “Aluminium Overcast”

Today was a long, tiring, but very productive day. It started out with a mad dash to the local equipment rental place in Pleasant Hill to return the impact driver (see Day 6) before they charged me for a second day. Then a quick stop at a bagel place to get breakfast before heading home.

The first order of business was to do the final prep of the TH-7DX yagi before sending it up to the top of the tower. This mostly consisted of tightening all of the hardware again, attaching the coax pigtail to the balun, and riveting one element that wouldn’t remain in place no matter how tight I tightened the hose clamp.

TH7DX TH-7DX Completed and Ready to Go Up

Steve then climbed the tower and attached a steel cable about half way up the mast. Steve attached the other end of the cable to the bumper of his truck parked on the other side of the garages and tightened it with a come-along. He attached two slings to the yagi on opposite sides of the mast clamp and attached the sling to a pulley. The pulley went onto the steel cable and was attached to a rope to pull the antenna up the cable. This technique is called a tram line and is a common way to get large yagis to the top of a tower.

TramLine Going Up the Tram Line

Steve waited at the top of the tower while Steve’s assistant and myself pulled on the rope attached to the pulley, which pulled the antenna up the cable towards the tower.

GettingThere Getting Close

Once the antenna was at the top of the tower, Steve grabbed it, wrestled it to the mast, and attached the mast clamp and securely bolted it to the tower. Once that was done, he attached the truss (used to reduce sag in the boom) and connected the coax and rotator control cables. While coming back down the tower, Steve fastened the coax and control cable to a tower leg. Once down, all that was left was to test the rotator to see if the antenna would rotate (it did), connect the antenna analyzer and verify the tuning of the antenna.

An antenna tuner is the best thing since sliced bread to a ham, because it’s a small, handheld device that lets you check an antenna’s SWR without a transmitter. It works by generating a low power signal (milliwatts) and analyzing the reflected power. Since the power is so low, it can even work outside the ham bands, useful if your antenna is resonating well outside one of the ham bands. The analyzer revealed that the tuning was spot on — close to 1:1 100 kHz up from the bottom edges of 20, 15, and 10 meters.

After cleaning up and gathering all his tools, Steve took his leave for the last time. It was a great pleasure to work with Steve throughout this project. His professionalism and skill made this project go smoothly.

A big yagi on a tower is a beautiful sight to any ham. I’m sure drivers on the local highway (about 1-1/2 miles from my QTH) will notice it.

Beautiful What a Sight!

The next step was getting coax and control cable to the shack. Last weekend I installed 160 feet of 2″ PVC conduit from the tower site to the wall outside the shack. This is mainly to prevent the wide variety of critters we share the land with from chewing through the cables. The first step in the process was to get a rope through the conduit that would be used to pull the coax and control cable. This was done by tying a plastic grocery bag to a spool of twine and shoving it into one end of the conduit. I then used a shop vac at the other end of the conduit to suck the bag and attached line through. The total transit time of the bag and line was about three seconds from end to end. I then used the twine to pull a larger 1/2″ poly line through the conduit. This larger line was needed to provide the strength needed to pull the cables themselves.

After attaching the coax, rotator control cable, and another piece of twine (to use in the future if any more cables needed to be pulled through the conduit) to the pull rope, I went to the other end of the conduit and pulled while Julie feed the cable bundle into the conduit on her end. Five minutes of pulling later, the cables emerged at my end. Piece of cake..

Cables W6JLG Feeding Cables into Conduit

Then it was just a matter of installing connectors, lightning arrestors, and plugging everything together. I finished all of the outside work this evening (with the aid of a clamp-on light), with the exception of drilling a hole in the wall of the shack and installing a piece of 2″ conduit to route the cables inside. That’ll have to wait until tomorrow as I’m zonked.

Then comes the real fun part — connecting the coax to the rig and firing it up. After 32 years of compromise antennas (ground-mounted verticals and low wire dipoles), this is an experience I’m really looking forward to. I hope the bands cooperate.


Tower Install – Day 6 “Erection”

After the concrete base had enough time to cure to the designed strength, the next step was to call in the crane and lift it into place on the base. We used a 95′ boom crane, and it barely make it up the hill, which is not for the faint of heart (or QRPers). We had to do some quick pruning to remove some overhanging branches that were blocking the driveway.

Pruning Pruning

Once the crane was in place, the operator lowered his outriggers (to give the crane greater stability) and had me sign a waiver in case the crane cracked the driveway. Steve connected two steel cables to the top of the tower and the driver started to lift.

ReadyToLift Ready to Lift

To the unpracticed eye, it looked like there was no way to lift the tower and clear all of the obstacles, but the crane operator made it look easy. He had the tower vertical and lifted over the garages and hanging over the tower base in less than a minute. Steve guided the tower down to the base where we connected the base to the first section of the tower using 1/2″ bolts and steel plates.

Touchdown Houston, Tranquility Base Here, the Eagle Has Landed

The next photo shows the overall view from the front of the house. 3900′ Mt. Diablo is the peak in the background on the right. In the right foreground is Mt. Wanda, named after Wanda Muir, the oldest daughter of John Muir, which is part of the John Muir National Historic Site. To the left of Mt. Wanda is Eastbay Regional Park land.

OverallView Overall View

Steve climbed the tower to detach the cables connecting it to the crane. I’m sure the view up there must be great!

DetachinCrane Detaching the Cables

The next step was the raising of the mast and inserting it through the thrust bearing at the top of the tower and connecting it to the AlfaSpid rotator sitting on the rotator bracket 8′ feet below the top of the tower. Steve rigged a sling around the mast, which the crane lifted while he waited at the top of the tower to receive it.

MastComingOver Mast on its Way

Once Steve wrestled the mast through the thrust bearing, which seemed like threading a needle to those of us on the ground, the rest was easy. With everything securely fastened, Steve removed the sling from the mast and climbed back down.

OverallViewMast Mischief Managed

By this point, the wind started to pick up and we decided to leave the raising of the TH-7DX antenna to tomorrow. I spent the rest of the evening assembling the major components of the antenna, which I had pre-built in the garage over the last month. Final assembly had to be done outside as the garage door wasn’t big enough to get it out. I also built the coax rotator loop and the section that comes down the tower. The DX Engineering cable prep tool certainly made this task easier, as did the crimp on connectors.

The last work done today was driving the ground rods. There are three 8′ ground rods at the base of the tower, one for each leg. There’s another rod right outside the shack where the coax and control cables enter the house. Although Northern California has one of the lowest frequencies of thunderstorms in the entire country, it’s still prudent to plan for the unexpected. When I’ve driven ground rods in the past, I’ve done it with a sledge hammer standing on a ladder. It’s hard work and the end of the rod usually ends up mushroomed. The solution is a rotary impact hammer with a ground rod bit, like the one shown below. This baby drives an 8′ ground rod home in about ten seconds with almost no effort and leaves the end nice and round.

Hammer Impact Hammer

Next update will be after we raise the antenna.