9cm Equipment

The 9cm band allocation (3.4Ghz here in VK) isn’t exactly bustling with activity around VK1  however I’ve wanted to add this capability for some time.

A 2W transverter is shown constructed from a number of both home brewed and kit modules. The heart of the transverter is one of Paul Wade’s evanescent mode waveguide filters in WR90.  I’ve used a Minikits crystal oscillator to generate a 542.67Mhz signal that is multiplied up to 3256Mhz as the LO injection to a surplus mixer module. The output of the filter is fed to a “front end” containing an MGA86576 MMIC for receive gain and a pair of MMIC’s cascaded to form the Tx driver, the signal path is switched using a PIN diode package.  About +10dBm output from this stage feeds a MiniKits PA to full 2W output.

While not the most compact design, the beauty of this approach is that each of the “modules” can be built and tested separately and it allows for a lot of variation in the components that are used.  The “building block” approach can be equally applied to higher frequency bands such as 5760Mhz and 10368Mhz without risking a lot of effort in board development and prototyping. The “front-end” module is equally suited to 13cm (2403Mhz here in VK).