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Baker Island Top Band Operator Offers Observations


Trying to work stations on 160 meters from Baker Island during the KH1/KH7Z DXpedition was fraught with challenges, and the WSJT-X FT8 digital protocol proved to be one answer to making contacts from the rare DXCC entity under tough, summertime conditions. DXpedition team member George Wallner, AA7JV, recently offered some observations about the experience that may be helpful to North American Top Banders. Wallner said the team was expecting easy conditions for Japan, which was closer, and difficult conditions for North America.

“We got the opposite. The band would open to North America soon after our sunset — around 1800 local time — with very little noise. North American callers were initially weak but easy copy. Noise would start rising about 2 hours after sunset,” Wallner said in a July 12 post on the Topband reflector. “Fortunately, that was about the time the gray line was reaching the east coast, which brought up the signals well above the noise. Some east coast signals were quite loud.”

Wallner said that as evening progressed, noise continued to rise from equatorial thunderstorms to the west. By the time Japanese stations showed up — about 5 hours after local sunset — noise was “way up,” and receiving conditions became difficult. Occasionally, KH1/KH7Z had to listen above 1.825 MHz for North America to avoid manmade interference (QRM) from Japan. A receive antenna installed later helped, but even then, many signals were better copy on the transmit antenna.

The US Fish and Wildlife Service (USFWS) oversees the island and approves visitors, and Wallner said, and only being allowed on the island in June with temperatures topping 100 °F was “the most onerous” limitation. A long way from ideal from a low-band point of view, but we were determined to make it work,” he said. “The result was over 1,500 QSOs on Top Band.”

The 160-meter transmitting antenna stood right at the high-water line, with its metal base buried in wet sand. “At low tide, the antenna’s base was 30 feet from the water’s edge, but fortunately, the sand below the antenna was always saturated with salt water,” Wallner said. Also, KH1/KH7Z was only allowed a maximum antenna height of 43 feet. One remedy was a “fat” dipole using multiple wires. Transmitter power typically was around 800 W.

After the second night of operation, the DXpedition constructed a 60-foot-long double half-delta loop (DHDL) facing northeast, equipped with a high-performance filter/preamplifier. A second DHDL was set up later that faced toward Europe.

“Although we knew that the chances for working western Europe were basically nil, we made a big effort to work as far west possible,” Wallner said. “[On] a few nights, conditions were favorable, and we got as far as European Russia.”

“After operating 7 straight nights on 160, my ears were ready for a break,” Wallner said. “We switched to FT8 for about 5 hours, using the regular QSO mode. With N1DG operating, we made about 120 North American QSOs in about 5 hours.”

Wallner said their FT8 operation on 160 meters revealed serious demand for FT8, which gets through noise very well and gives modest stations a chance to work serious DX on 160. He said the KH1/KH7X team not only learned that 60-meter DX is “more than possible” in June and July, but for best results, operators need to be on the band every night to avoid missing anything.

Also: “FT8 is now part of Amateur Radio, even on 160 meters,” he concluded. — Thanks to The Daily DX