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  • New Microwave, UHF Distance Records Set on Same Day

    From ARRL de WD1CKS@VERT/WLARB to QST on Tue Jul 5 20:00:51 2016
    07/05/2016

    New distance records were set on 47 GHz and on 902 MHz on June 30 by stations at vastly separated points on the globe. On 47 GHz, US and Canadian operators set up on Whiteface Mountain in New York (FN34bi) and on Mont Tremblant in Quebec (FN26rf), respectively, in the effort to set a new North American record on the band. The distance was calculated at 215 kilometers (133.3 miles). On the US side were Mike Sequin, N1JEZ, and Henry Ingwersen, KT1J; on the Canadian side were Rene Barbeau, VE2UG, and Ray Perrin, VE3FN.

    "On this band, we usually are working line of sight," Sequin said. "We have a lot of experimentation to do, now that there are some good high-power amps available." He said the June 30 attempt marked the second 47 GHz contact for VE2UG and VE3FN. A week earlier, they had worked both KT1J and N1JEZ over a 99-kilometer (61.4 miles) path, with signals peaking almost 60 dB out of the noise.

    Once everything was in place on the big day, Sequin was able to hear Barbeu's CW signal almost immediately. "Signals were not strong, with a lot of QSB," Seguin said. Once they aligned their dishes, each operator worked the others. Following the successful 47 GHz contacts, VE3FN and N1JEZ worked each other "easily" on 24 GHz SSB.

    Meanwhile on the Pacific side of the world, Wayne Overbeck, N6NB, and Greg Campbell, W6IT, set a new world DX record on 902 MHz between California and Hawaii. They took advantage of a transpacific tropo duct to complete a contact over a path of 4095 kilometers (2544 miles), topping the old record set more than 20 years ago of 4064 kilometers. Last year, Overbeck and Campbell set world distance records on 2.3 and 3.4 GHz over the approximately the same path.

    "This record contact again underscored the degree to which these record-setting attempts involve good luck as well as planning and preparation," Overbeck said. Not since the tropo duct that allowed Campbell and Overbeck to set their microwave records last year had another occurred, until June 30. "This duct only produced good signals for a matter of a few hours," he recounted. He said he and Campbell both managed to be in the right place at the right time to set the new 902 MHz record. "Three hours later the duct dissipated and transpacific signals faded into the noise," he said. "Some ducts have been known to last for as long as 8 days, but this one was gone in a few hours."

    N6NB operated from Hawaii using a suitcase portable station in a rented vehicle at 5260 feet elevation on Hawaii's Daniel Inouye Highway, while in California, W6IT used one of N6NB's rover stations to operate portable 75 miles inland and at 6200 feet elevation.

    "That strategy was admittedly risky," Overbeck said. "The transpacific tropo duct, which occasionally allows VHF+ signals to travel from the West Coast to Hawaii, usually occurs at a low elevation on the California end, but at a high elevation on the Hawaiian end."

    He said there have been occasions when California stations on coastal mountaintops could not get into the duct, while stations at much lower elevations were easily able to work into Hawaii.

    "The duct usually breaks up near the shoreline on the California end," Overbeck said. "Sometimes stations on a mountaintop that is far enough inland but still line of sight to the coast can put a signal into the duct from afar at a low angle. W6IT's location at an overlook on Rim of the World Drive is that kind of place - far inland but line of sight to the ocean." 

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