VHF/UHF weak-signal operators across North America are making the final tests on their stations in preparation for the ARRL UHF Contest, coming up the weekend of August 7-8. Most VHF+ weak-signal operation takes place on the two lowest bands of the VHF spectrum -- 6 and 2 meters; however, there is a lot of activity that takes place above 144 MHz in the UHF portion of the radio spectrum and beyond. This contest focuses on 220 MHz and above; there will be lots of activity, and hopefully lots of propagation, too!

With much of the nation in the midst of a summer heat spike, high-pressure zones can begin to form in the atmosphere. If they stick around long enough -- and are stable enough -- enhanced propagation can occur in the troposphere, extending the normal usable range of UHF+ frequencies from line-of-sight to several hundred miles. Several cloudless days with very little wind is a sign that enhanced tropospheric enhancement could be coming your way. A great site to watch for tropospheric enhancement is William Hepburn’s tropospheric ducting forecast page.

“If you’ve never made a QSO in the UHF Contest, this is a great time to start,” said ARRL Contest Branch Manager Sean Kutzko, KX9X. “While the lowest band permitted in the UHF Contest is 220 MHz, the most-active band is usually 432 MHz. Many of the ‘DC-to-Light’ rigs being offered today have 432 MHz in them, and antennas are reasonably small. There are many commercial Yagi or horizontal loop antennas that can be purchased very inexpensively, and you can find easy homebrew UHF antenna plans in the ARRL Antenna Book and The ARRL Handbook.” Kutzko explained that a good beginner’s station should have a 220 MHz FM radio with a vertically-polarized antenna, as well as a 432 MHz rig that can work SSB/CW and a horizontally polarized antenna, such as a Yagi or loop.

“You’ll see some activity on 220 MHz FM, especially if you live near a large population center,” Kutzko said. “Monitor the national FM calling frequency of 223.5 MHz for activity. Be prepared to move off the calling frequency should conditions warrant. For 432 MHz SSB/CW, the frequency to monitor is 432.100 MHz. Again, be prepared to move off the calling frequency if there are excellent conditions; too many people on the calling frequency makes for some tough conditions to copy signals. It’s bad form to monopolize the calling frequency.”

So where should you operate from? Certainly your home is the obvious choice, but because antennas are so small and portable -- as are many of the rigs -- operating from a hilltop is very easy, Kutzko explained. “Equip yourself with 10 to 15 feet of mast and set it up next to your car on a high point in your area and you’ll be in business!” The contest exchange is simply your Maidenhead grid square. You can even be a “Rover” and operate from your car from more than one grid square.

The ARRL August UHF Contest runs from 1800 UTC Saturday, August 7 through 1759 UTC Sunday, August 8. Find the complete rules on the ARRL Web site. Logs must be received by 1800 UTC Tuesday, September 7, 2010. Cabrillo-formatted logs should be submitted via e-mail. Paper logs should be sent to August UHF Contest, ARRL, 225 Main St, Newington, CT 06111. Here’s hoping to see you the weekend of August 7 on the “Ultra-Highs!”