2-3 GHz Up/Down Converter to 432 MHz
Last Modified March 31,2003
This unit was designed by the late Sam Luitwieler, K6VLM for his modification
of the Pcom 23 GHz ODU to a 24 GHz Transverter. It is designed to convert the 1st
i.f. frequency of the modified Pcom Tx and Rx Modules to a 2nd i.f. of 432 MHz. The
Tx and Rx r.f. input/output signals are in the range of 3072 MHz for the low side
LO version of the Pcom units, and 2208 MHz for the high side LO Pcom units. SBMS
had a number of pc boards made, and parts kits are being made available, at cost
to amateurs. This pc board is also known as the 3072 Mhz U/D Converter, or the "Mixer"
Board. It is more than just a mixer, however. It operates in either up or down conversion
modes depending on the dc voltages applied. The board contains active amplifiers
to boost the 2.5-2.7 GHz 2nd LO signal and the i.f and r.f.signals, and includes
PIN diode switching.
The following drawings comments and photos are provided to help you assemble
U/D Converter. Schematic Diagram. Parts
List. Photo of pc board showing that the green "resist"
still covers some of the pads where parts must be soldered. An enhanced
photo showing where this resist must be removed by scraping. Preparation
details for the board.
***WARNING*** Describes a problem
with the PIN diode polarity. Layout Dwg#1,
Dwg#2. Finally, a photo of the completed kit assembled by Greg
For those interested in the SBMS kits, contact Ken Halford, WB6DTA at 2901 Joaquin
Dr., Burbank CA, 91504. The kits include the pcb and the mixer, MMICs, PIN diodes,
rf chokes, chip Resistors and Caps, but not the connectors or DRO Synthesizer. There
are a limited number of kits available.