Summer 2007 Issue

A Simplified Path to
a High-Performance 10-GHz Transverter Sy

With the increase in popularity of the 10-GHz band, KH6WZ has risen to the challenge and created an X-band transverter that is quick to build.

By Wayne Yoshida, KH6WZ

Photo A. Box of ingredients needed to form a complete 10-GHz transverter. Available surplus is changing, and the new challenge is moving from “where to get parts” to “where to find the time to build it.” (All photos and artwork by the author)

The challenge: Get another X-band transverter built quickly for a fellow club member who has been procrastinating for over a year about getting on the 10-GHz band. The solution: Get in there and help him build it!

We wanted to see how quickly a 10-GHz transverter could be built using readily-available components and surplus modules. All we needed were the “ingredients” for the system, some free time to build, some knowledge of how the modules connect together, and a good technical friend with test equipment for the microwave bands. This last ingredient was probably the most important, since the ability to test the unit (as well as surplus parts) requires some specialized gear. Fortunately, I have access to such a resource: my fellow San Bernardino Microwave Society (SBMS) club member, Dave Glawson, WA6CGR. Other microwave-specialty clubs have their cadre of experts, and most of them are willing to help others.

The box of parts can be seen in Photo A. This box of ingredients includes a 1-watt, solid-state power amplifier (SSPA), all tuned up and tested for use at 10.368 GHz! The amateur radio X-band scene is changing rapidly, since parts are becoming easier to acquire. The challenge is moving from “where do we get parts?” to “where do we find the time to build a system?”

An enhanced, “competition class” 10-GHz rig would include a receiver pre-amplifier (low-noise amplifier, or LNA), a 2-foot (or larger) dish antenna, and a power amplifier putting out a full 1 watt (30 dBm) or more. The rig described in this article is just such a unit, with a receiver noise figure of less than 1 dB and about 23 dB conversion gain. Nine-hundred milliwatts at 10368 MHz appears at the antenna port (see Photo B).

It’s a New X-Band World

In 1993 Zack Lau, KH6CP (now W1VT), ran a two-part article in QST magazine about building a 10-GHz transverter from “scratch.”1,2 Zack’s project simplified parts procurement by eliminating surplus “brick” oscillators and exotic surplus, and the bill of materials called for off-the-shelf components.

As mentioned, today’s surplus availability has changed radically with online auctions and other resources, including fellow club members with access to some fairly complex components such as waveguide relays and mixers. One of the biggest “boosters” on the 10-GHz ham radio front is the availability of QualComm modules, sub-assemblies, and modification instructions made available to hams.

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