Wavelab Transverter based 24 GHz Rig




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In the spring of 2023 a friend put me on to some surplus 23 GHz transverter modules being offered by a Polish seller on eBay. These 23X1008XP modules were removed from NOS Wavelab Advanage Series ODUs (Outdoor Units) that were intended to be used for wireless microwave communications and broadband networks. The modules contain all of the 23 GHz RF mixer, filter and amplifier circuitry but still needed Local Oscillator signals, I.F. input attenuation and related supply voltages to make them work as 24 GHz transverters.
The ham community soon caught wind of these modules and an IO Group was formed out of the sudden interest. It was there that I learned of a Belgian Ham PA0HME who had designed a plug-in pc board that contained all of the remaining required circuitry to form a functioning 24 GHz transverter. It sounded like a viable project so I went ahead and ordered a few Wavelab modules from Poland. American Ham KM5PO from the North Texas Microwave Society ("NTMS") put together a group buy for the PC Boards with the required components preinstalled at the board house. I ordered 3 boards for the modules that I had already purchased on eBay. It turned out that there were some shortages for components that the board house did not have in stock so the boards arrived incomplete. The remaining missing parts were ordered from Mouser, then I completed all 3 of my modules but only one of them worked from the get go. I discovered some solder shorts on a few compnents and unmelted solder paste balls & excess flux residue under the synthesizer chips that prevented them from starting up reliably. After removing the solder shorts and cleaning them up I had 3 working modules. I also did the modification (simple cut of a trace) to disable the internal TX attenuator to ensure the TX power is set to maximum. These modules are specified for ~3.5dB RX Noise Figure and around 2 Watts of transmit power. I built one of the modules into a complete 24 GHz rig which is described below.


Equipment details:

I used a 12" spun aluminum dish with a WR-42 flange and a penny feed that I acquired a few years ago.

I purchased a suitable enclosure from Amazon to keep everything somewhat water resistant as I've been known to operate in rainy and snowy conditions. The Wavelab module and all boards are mounted to a 3/16" thick aluminum backplane that replaces the plastic backplane that came with the enclosure. The aluminum plate also serves as a heatsink to keep the module and power supply components cool.

A CTI 10 MHz OCXO on a pc board of my own design is used as a stable reference for the Local Oscillators on the plug-in board.

I used one of my adjustable linear High Current Regulator boards to supply 6.5V to the module. The Regulator board has provision for up to 4 pass transistors (20 Amps) but the Wavelab module only requires a few Amps so I cut the board and only populated one pass transistor to keep it small.

A Ducommun latching type relay is used for RX/TX antenna switching and there's a W6PQL latching driver board mounted under it. These relays have relatively low loss at 24 GHz and work surprisingly well.

12VDC, 2M I.F. and PTT connections are brought out to the bottom of the enclosure.


First Tests:

My first contact was a direct QSO with VA3ELE @ ~ 25km. The next two contacts with VE3KH and VE3HPC came by way of ~90km bounce shots using tall buildings in downtown Toronto as I don't have a direct shot their way from grid FN03an. VE3HPC was also using his Wavelab 24 GHz rig.


204km Wavelab to Wavelab:

On Sept.11, 2024 I made a 204 km contact with Andy K0SM who was also using a Wavelab rig. I was in grid FN03an just north of my home and Andy was in grid FN12eu on his driveway. Both rigs were barefoot with ~2 watts, no external LNA and a 12" dish.
Video here: Wavelab to Wavelab VA3TO - K0SM @ 204km ...so these modules just work !


The proliferation of these relatively inexpensive modules along with the good work of a few hams has lead to significant increase of 24 GHz equipped operators as witnessed in the 2024 10 GHz & Up Contest !




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