UARC Homebrew Night 2006

Thursday, October 5, was the night for UARC's annual homebrew exhibition, a time when people can show off home-built amateur radio equipment. Here are some of the highlights as captured by club photographer Ron Speirs, K7RLS.

Chuck Johnson, WA7JOS, constructed a device to facilitate networked logging on Field Day. It interconnects lines from the various stations and includes regeneration of the RS-232 signals and bypassing of any station whose computer is accidentally shut down. Its weatherproof box allows it to be left outdoors in the rain. Chuck's second project was an amplifier to drive multiple sets of headphones and control the volume to each one independently.

Tony Naef, KE7BBG, showed a printer interface for an Atari computer and an "Easter Egg" from a Tektronics oscilloscope.

Ned Stevens, K7ELP, shows off a 6-pole weatherproof remote antenna switch. He also showed an electronic name badge that would diplay his call in scrolling LEDs.

Dale Heisler, WJ7L, built a sequencer to solve a problem unique to mast-mounted preampifiers. A preamp at the antenna solves the problem of degraded receive performance due to coax loss. A pitfall, however, is that transmitting while the preamp is still connected can destroy the preamp. The sequencer makes sure that components of the station go on and off in the right sequence during the switch from receive to transmit.

Club Secretary, Dick Keddington, KD7TDZ, built a 24-hour clock that includes two hour hands so that local time and UTC can be displayed simultaneously.

Eugene McWherter, N7OVT, shows off a sleve dipole. Eugene also showed a battery state checker.

J.J. Wallace, KE7GHK, put together a portable repeater that can be deployed as needed and set to whatever frequency pair is available.

Ron Speirs, K7RLS, demonstrates a keyer using touch sensing rather than the traditional mechanical contacts.

Ron's second project, a favorite of the audience, showed how to make good use of a pair of old CB radios: They make great bookends!

Chris Perri, KE7FYP, shows a collapsible, 5-element, two-meter Yagi. The design, from one of the ARRL publications, uses a modified FM broadcast antenna available from Radio Shack.

John Brewer, N7MFQ, UARC Executive Vice-President, built an interface to a computer sound card for use with the computer digital modes such as PSK-31. John's interface was used successfully at UARC's PSK-31 station during last June's Field Day entry.

Ron Jones, K7RJ, built a pair of light transceivers using pulse-width-modulated laser pointers as the transmitters and photo diodes as the basis for the receivers. The project was done almost entirely on the night before the meeting. Here, he sets up to communicate across the room with his XYL, Elaine, N7BDZ. At one point in the setup he commented, “We seem to be getting some static.” Elaine's response brought the house down:

“I'm supposed to give you static, Ron. I'm your wife.”

Tim Purser, WB7CIW, shows an audio amplifier he built many years ago as an eighth grade Science Fair project. He particularly wanted to give credit to the teacher who inspired him to learn about electronics.

“Woody” Woodruff, KC7YLH, built a collapsible two-meter J-pole with a PVC base support. The J-pole is made of copper pipe sections held together with bungee cord as per a QST article. Woody says the antenna can be set up in a driveway in a very few minutes, and is useful for attracting questions from the public as well as providing a quick antenna for emergency situations.

Clint Turner, KA7OEI, shows his unit to control Gunnplexer units on the 10- and 24-GHz bands. His box is unique because it measures temperature and makes adjustments to the tuning voltage to compensate for the Gunnplexer's normal frequency change with temperature. This improves frequency stability by a factor of 10-to-1 over using a fixed voltage. The controller can be pre-programmed with information about the temperature curves of several different Gunnplexers.

Brett Sutherland, N7KG, shows his partially completed Gunnplexer controller.

John Bradshaw, KA7TGR, shows a power cord with a series light bulb. This device is useful for gently powering up old consumer radios such as the famous Zenith “Trans-Oceanic” made in several versions during the 1940s. John has done extensive restoration work on many antique broadcast radios.

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