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Tuesday, June 23, 2015

Sidecat Anchor Replacement

The broken anchor.
One of the causes for antenna one's damage during the typhoon was that the anchor for the support cable on the side of the antenna was ripped out of the ground.  This anchor is hooked into a reinforced cement block buried under about six feet of earth.  Over years of oxidation and corrosion, certain spots on the anchor became thinner and thinner until the anchor broke in half during the strong gusts of the typhoon.  This break increased the stress on the other support cables, and resulted in broken drop lines and the tangled web of metal and ceramic insulators shown earlier.

In order to prevent this from occurring on all the other anchors, we had poured a cylindrical concrete form to protect the anchor from corrosion and add additional stability and strength.  However, this had not been done to the anchors on antenna one before the typhoon.

Temporary "anchors".
To fix antenna one's anchors, we temporarily connected the side support cables to two vehicles to hold the antenna in place while we fixed the anchors.  Next, we dug holes to get to the buried concrete blocks, and chipped away concrete to expose the steel rebar so we could attach the new anchors.  Once we attached the anchors and set them at the proper angle and direction, we poured the concrete into cylindrical forms around the anchors.  The next-to-last step was to backfill the holes we had dug, and to wait two weeks for the new anchors to set.  Finally, we reattached the side support cables to the new anchors and tensioned the cables to the proper load.  And just like that, antenna one was completely repaired!

Reattaching the anchor and pouring the concrete tube.
Backfilling around the anchor with dirt.
The cables are reattached to the anchors, much to Sol's delight.

Thursday, June 11, 2015

Slew Switch Motor Replacement

Since the beginning of the broadcast season in March, we have been limited in our use of antenna three.  Although the antenna can potentially broadcast in three directions, we can only use one of those directions (or slews) per shift.  This is because the motor that powers the slew switch has not been working properly.  In order to restore the slew switch to its proper functionality, we replaced the old motor with a refurbished motor, and replaced the wires that run from the relays that control the motor to match the color-coded system in our schematics.

Now that the motor has been replaced, we have the potential to use any of the three slews on antenna three during our broadcast shift.  However, this improvement came with a cost, as Mike painfully discovered where some wasps had been nesting in the struts that support the slew switch...

Transmitter Maintenance

Since the site has been in project mode for so long, continuously working to improve the operation of the site, it has been difficult to keep up with the scheduled maintenance of the transmitters.  However, with our new intern, Sol, and the Brunson family, who are here on Guam for a vision trip as they work towards raising financial support to join the team, we have the manpower to perform some overdue maintenance of the transmitters!

First up, our 100kW HCJB transmitter!  We vacuumed out and wiped down the different compartments of the transmitter, changed the water in the cooling system, replaced the weatherstripping on the doors of the modulator cabinet, and visually inspected for any damage.

Next up, our two 250kW Thomson transmitters!  We opened up the transmitters, cleaned all the different compartments, and visually inspected for any damage.

It was helpful to have the manpower necessary to complete these tasks in one day.  We are looking forward to the day when all of those raising support to join the team here on Guam, so we can keep up to date with these tasks that help ensure the reliability that we strive for!

Antenna Repair

 As you all know, the transmitter site was hit by Typhoon Dolphin back in mid-May.  It is definitely past time to inform you all about how the repairs are going!  The week after the typhoon hit, we immediately went into recovery mode.  We contacted local churches to assemble crews of volunteers to come out and help with the repairs.  We also had our friend, Sterling, come out from the States to help with the antenna rigging.  It was encouraging and exciting to see so many people sacrifice time and energy to help with the difficult task of getting the antenna back up and running!

The first major task was to lower the broken antenna.  Sterling and Andrew climbed the antenna towers to attach clamps to the top support cable of the antenna.  They disconnected the broken antenna and reflector screen from the towers, and the team used a system of cables and pulleys to slowly lower the antenna safely to the ground.

Once the antenna reached the ground, our hearty crew of volunteers worked to separate the screen from the antenna (above).  The act of lowering everything down at once, while the safer option, caused the screen and the antenna to get tangled up.  It took a few hours of careful puzzle-solving to separate the two.

After we separated the antenna and the reflector screen, our crew went to work scouring the antenna dipoles and replacing any broken pieces (left).  Next, we patched the antenna dipoles back together and slowly raised the antenna back up, row by row (below).

A week after Typhoon Dolphin damaged our antenna, we were back up and running!  We are grateful for all the volunteers' help, thankful for no major injuries, and we praise God that the switch matrix allowed us to shift programming around in order to minimize the loss of air time!