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Friday, June 10, 2016

Final Dummy Load Update


In 2010, the staff at KTWR began the intricate Transmitter Replacement Project (see the post from July 13, 2010). It has taken many hours of hard labor, fundraising, and prayer, and this year the completion of the Dummy Load installation marks the end of this incredible project.

You can follow the progress of this project by reading through the blog posts from the past six years, but in summary, it has involved the retiring of one of our transmitters and the installment of two new transmitters, known as Thomson transmitters. These new transmitters are capable of broadcasting using DRM (Digital Radio Mondiale) technology, which means we can transmit analog
shortwave broadcasts with digital quality. Using DRM technology allows us to reach a wider audience with better sound quality—and is there a more worthy message that deserves to be communicated as clearly as possible than the Gospel of Jesus Christ?

The Dummy Load installation began last year (see the post from July 27, 2015) and was completed this March. The Dummy Load is important because it acts as a sort of fake (or dummy) antenna, allowing our engineers to test the power of the new transmitters. Sometimes when broadcasting, the transmitters indicate that they’re using the correct amount of power when they really aren’t. We want the broadcasts to reach the right people in the right places, so transmitting with the right amount of power is crucial. If the real antennas were used to check the power output, we would risk interfering with other broadcasters. Because of the Dummy Load, we can now appropriately measure how much power the transmitters are actually putting out to ensure our listeners hear the Word of God.
Not only is this equipment used for power measurement, it also gives us a way to perform other tests that require the transmitter to be putting out a signal without the aforementioned interference issue. The Dummy Load has been tested, it works, and we praise the Lord for it!


Let the favor of the Lord our God be upon us,
and establish the work of our hands upon us;
yes, establish the work of our hands!
Psalm 90:17


These are the resistors of the dummy (test) load that act as an antenna so the power from the transmitters can be tested. These resistors are situated inside a concrete enclosure for protection against the often punishing elements here on Guam.

The metal box to the far right is the chiller, which is needed because when testing the transmitters a large amount of energy is sent to the test load, creating a lot of heat. The beige structure directly to the left of the chiller is the concrete structure surrounding the dummy load. The series of metal boxes and black lines directly to the left of that is the switch matrix. This matrix connects the transmitters to the antennas and increases broadcast reliability. If a transmitter or antenna fails, it allows our operators to switch the power from a different transmitter or to a different antenna so we can continue broadcasting. It also gives us flexibility in choosing which transmitter/antenna combination is the best for reaching particular audiences. By hooking up the Dummy Load to the matrix, we are able to switch the power from the antennas to the Dummy Load so tests can be run.

The KTWR site to date. You can see the Dummy Load and matrix center-left, between the KTWR building and the antenna field.

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