Our goal for this phase of our EME Station Project is to get our new tower up, install the Azimuth Rotator and Mast, and run the hardline and coax cables for our antennas from the shack to our new tower. Our EME tower is constructed using Rohn 55G tower sections. It will be 26 ft tall and will have approximately 18″ of our 3″ mast protruding above the tower. The tower is a free-standing/guyed hybrid design with the first section being cemented into the ground.
The base section and the three guy anchor blocks were completed a little while back. The holes were backfilled and we’ve given the cement a couple of weeks to cure.
Matt, KC1XX, and Andrew of XX Towers began by installing a winch and a gin pole on the base section of the tower. They used the Gin Pole to hoist the second tower section into place and secure it. They also attached the top plate to the third tower section in preparation for installing it along with our mast.
It is always a challenge to install a mast inside a new tower. The mast we are using is a heavy, 22 ft 4130 chrome molly steel mast that weighs over 250 lbs. Getting the mast inside the tower was quite a feat! Matt and Andrew rigged the top tower section and the mast together and pulled both up together on the Gin Pole. Next, one leg of the top tower section was attached and a second pully was used to pull the mast up through the top tower section until it could be placed inside the tower. The last step was to raise the top tower section a second time using the Gin Pole to seat it on top of the rest of the tower. Finally, the mast was lowered inside the tower to the base and the top tower section was bolted on to complete the tower.
The next step involved attaching the upper guy anchor bracket to the top section of the tower and rigging the guy anchor cables. We decided to use Phillystran Guy Cable to avoid interactions with our antennas.
The completed cables are tensioned using turnbuckles. We adjusted the cables to plumb the tower and then safety-wired the turnbuckles so they will not come loose.
The next step was to install an M2 Antenna Systems Orion 2800G2 Azimuth Rotator in our tower. The use of the 22 ft mast allowed us to place the rotator about 5 ft above the ground where we can easily service it in the future. The long mast also acts as a torque shock absorber when the rotator starts or stops moving suddenly. With the rotator in place, we attached the mast and clamped it at the rotator and thrust bearing at the top of the tower.
The last step in our project was to install our coax cables and hardlines on the tower and run them through a 4″ underground conduit to our shack. We pre-made the two LMR-600 coax cables for the receive side of our EME Antenna System previously. We cut a section of LDF5-50A 7/8″ Hardline to approximately the same length as the LMR-600 coax cables.
We used a cutoff plastic bottle to protect the ends of the coax cables and hardline as we pushed them through approximately 50 ft of buried 4″ conduit. The conduits were constructed to create a gradual turn into and out of the ground and the cables went into the conduit smoothly.
With the cables in place, we installed N-female connectors on each end of the 7/8″ hardline. We used rubber reducers to make it easier to deter water from entering the conduits where the cables exit.
We expanded out main shack entry ground block using an 18 position tinned cover ground bar from Storm Copper to make room for additional static arrestors for our EME Antenna System. The LMR-600 receive-side coax cables and the 7/8″ hardline connection for the transmit-side of our EME antennas terminate on N-connector Static Arrestors from Alpha Delta.
Our new EME tower is complete and ready to accept the Elevation Rotator, H-Frame, and Antennas from M2 Antenna Systems when they arrive. We plan to complete the grounding system and get the Azimuth Rotator hooked up and tested with our Green Heron Engineering RT-21 Az/El Rotator Controller in the near future.
Here are some links to other articles in our series about our EME Station 2.0 project:
- EME Station 2.0 Part 1 – Goals and Station Design
- EME Station 2.0 Part 2 – Excavation, Footings, and Conduits for New Tower
- EME Station 2.0 Part 3 – Phase Tuned Receive Coax Cables
- EME Station 2.0 Part 5 – Control Cables and Rotator Controller