Frequency synthesizer for my Jupiter receiver — Радионова 1 — [ Radionova 1 ]
Greetings! Most of my future homebrew radio projects will focus on building radio astronomy gear.
Radio astronomy offers much fun + learning for the radio homebuilder — example topics include how to design and make antennas, LNAs, receivers, and frequency synthesizers from HF to microwave. Further we may craft op-amp analog integrators to remove background noise, and/or ADCs, plus write software to store and analyze our data. Avid radio astronomers enjoy a strong understanding of noise measurement/physics, plus a whole lot of really cool science. I’ve already made new friends and feel inspired by the dedicated, skillful folks who listen to signals from space on stuff they craft in their home labs. In radio astronomy, Dx might mean receiving signals from 590 million kilometers away. I’m in!
Listening to the Jovian bursts from Jupiter seems a good place to start. Single sideband radio telescope receivers from about 18 – 24 MHz work for Jupiter, however, the single most common frequency = 20.1 MHz. Listening at 20.1 MHz avoids 20 MHz WWV and lies above the earth’s ionospheric cut-off frequency avoiding some human caused night-time interference.
For my Jupiter receiver, I sought a 20.1 MHz or so local oscillator with a little frequency agility to steer around local interference. Invigorated by 4 months of studying PLL design, for Radionova 1, I built a simple, from-scratch PLL-based synthesizer that runs from ~20.117 to 20.666 MHz with no MCU.
With sincere thanks, I borrow heavily from the published work of Wes, W7ZOI.
Above — Block out diagram. I’ll share some of my design notes for most of the stages in this diagram.
I suggest you study published PLL books plus read the many great online articles concerning PLL-based synthesizers, demodulators and quadratures since I’m a mere beginner when it comes to PLL knowledge and experience.