I built two radios for 79 GHz since there are so few people to talk to, and since I have no test equipment for 79 GHz, it allows me to test functionality.
The first radio shown here was built into a case and antenna that I found at the local electronics swap meet.
On the inside it looks like this:
The second radio was built into a custom case and uses a precision made Cassegrain type antenna from Japan. This stunning antenna was made by a group of amateur radio operators.
Here’s the radio itself:
Reactance Labs got its start with the PLL synthesizer that forms the basis of the LO in this radio. It all starts with a 2.5 Ghz synthesizer, goes into a times four multiplier and then into another times 4 before it goes into the mixer at nearly 40 GHz.
The mixers in this radio are super simple anti-parallel diode pair mixers. They are epoxied onto a hand-drawn and etched 5 mil duroid. The housings were made on my milling machine.
A view of the upper half of the housings
These radios are just a start on 79 GHz. I’ve used the second radio to make a couple 2km contacts. More to come!