Fall 2009 Issue

California Hams Take 10-GHz
Contesting to the Extreme!

Combine extremely high frequencies, extremely low power, extremely good weather with extreme enthusiasm and what do you get? The answer is in the results of the ARRL 10 GHz and Up contest. WB6NOA describes the activities of California hams on 10 GHz.

By Gordon West, WB6NOA


San Bernardino Microwave Society “tine-up” party held each year before the ARRL’s 10 GHz contests.

As California hams, we need to continuously upgrade our image at every opportunity. This includes wild and wacky stations set up during the ARRL 10 GHz and up two-part contest held in August and September every year. First, we have activity monthly, thanks to the San Bernardino Microwave Society (<www.ham-radio.com/SBMS>). It even televises its meetings over ATV via the ATN network!

We have a good number of hams on board, about fifty southern California operators during the contests, plus another couple of dozen in the San Francisco Bay area. Some are old hands at this with their own homebrew transverters, and some are new hams with DB6NT transverters for nearly plug-and-play to any 10- or 2-meter multimode low-power transceiver (www.SSBUSA.com/ham). We don’t stop at 10 GHz either. For every dozen X-band rigs, there is at least one 24-GHz operator, plus a few higher up in the bands as well.

Each year, a month before the ARRL’s 10 GHz contests the San Bernardino Microwave Society holds a “tune-up” party at a big open park, serving up a well-calibrated antenna range. Each station gets a down-range ERP (effective radiated power) measurement, and all stations compete to be the last receiver standing as the down-range test signal drops into the ozone.

“The best part is eyeballing how the gear hangs on to the antenna system!” comments Bill Alber, WA6CAX. “Some of the most bizarre-looking lash-ups did best in the tune-outs,” he adds, shaking his head at some of the wild open-wired rigs with almost half running below 1 watt output. Most of the traveling-wave tubes could be seen resting comfortably in the back seat, not pressed into action during this short-range shootout. (Measured ERP = power meter reading, plus attenuator, plus path loss, plus cable and mixer loss, minus amplifier and horn gain.)

In southern California, we have the luxury of working on our receivers at home, getting tuned up for picking up four continuous X-band CW beacons: 10,368.300 MHz, N6CA, Palos Verdes; 10,368.310, N6CA, Frazier Mountain; 10,368.330, KE6JUV, Santiago Peak; and 10,368.070, WB6IGP, San Diego.

In the Bay area, these beacons serve the bench tech well for final receiver tune-ups: 10, 368.325, W6ASL, Mt. Vaca; and 10,368.020, KK6TG, Mt. St. Helena.

Much credit goes to Paul Lieb, KH6HME, who is always ready to drive to the top of the Mauna Loa volcano to light off 10.368.350 MHz, the KH6HME Mauna Loa beacon, yet to be heard here on the mainland.

For the 2009 contest, there were even digital modes on 10 GHz, including JT65, along with PSK-31. Word has it that a few exchanges were accomplished.

However, likely the most SSB exchanges came from the monster signal of Robin, WA6CDR, high atop Nevada’s Mt. Potosi, DM25GW, using an undisclosed amount of power and his 6-foot dish. His incredible signal and receive system was able to give a knife’s edge over the Sierra Nevada snowcapped mountain range to link up with stations north of the Bay area. Robin is also the control operator for the Cactus linked repeater system, serving as the UHF coordination channel, with multiple repeaters tied in for the party-line effect.

The 10-GHz operators on UHF coordination sounded a bit like air-traffic controllers, passing instructions in less than 3 seconds, making listening even to the intercom channel a thrill (and very important!).

“NOA, CDR, my carrier to you on 175.”
“CDR, NOA, have your carrier, drop and listen to mine.”
“NOA, we got a peak; go sideband now.”

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