Amateur Radio Restart Project (2024/04/29) |
On January 17, 2016, lightning struck an antenna, damaging all of our radios and home appliances. My main FTDX3000 broke, so in March 2018 I bought a new FTDX3000 from Tomei Electronics and had them send it to me.
However, the 20mH coconut tree that was used as a tower It was cut down because it was old and in danger of falling over.
Before they were cut down, the three coconut trees had four full-sized Yagi antennas. Each band was attached with a fixed beam.
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It's only in the Philippines that you can be such a happy free tower owner. A homemade 14MHz 3-element Yagi antenna installed for Europe. It flew well.
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I attached a 7MHz dipole antenna to the remaining 20m pipe tower. Because there is a tower at the edge of the site, an inverted V is not possible, so a diagonal dipole is used.
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The power supply is a cutting board purchased from a general store. The handle of the cutting board fits perfectly into the coaxial holder. I couldn't find a balun for sale, so I followed the advice of JQ2GYU's Sakurai-san and installed three snap cores.
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You can find all the electrical wires and parts at UNITRUS in the town of Ozamiz.
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To adjust the antenna, pulleys were attached to both ends of the element so that it could be raised and lowered. This is also advice from JQ2GYU Sakurai, a DXer who owns two crank-up towers. He also uses pulleys to adjust the low band dipole.
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The cutting board of the power supply part is processed so that no force is applied to the shaft connector. It also serves as an element holder instead of a corrugated insulator.
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I adjusted the element length using the NanoVNA-H4, which I bought online in the Philippines for 4,200 pesos (about 11,500 yen). The lowest SWR was 7.090MHz for 7MHz.
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However, 21MHz has the lowest SWR outside the band of 22.140MHz. When I was searching for information on the Internet, I found something similar on YouTube's "Momo Channel!"
https://youtu.be/LbjRYRG9x9I?t=487
I will write about how to connect a 21MHz antenna to a 7MHz antenna in my diary on May 3rd.
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April 04, 2024 April 30, 2024 |