The Mini-Kits EME175-R3 is an updated design that uses a Butler oscillator with 5th overtone crystals which can be used to cover frequencies between 400 to 640MHz. The design is a modern redesign of the popular butler oscillator design of the early 1990's, and has a number of design changes to improve the oscillator phase noise performance. The oscillator will provide a stable +7dBm output, and is suitable for Transverters and RX Converters from the UHF to Microwave bands. The Oscillator has the option to add components so that it can be voltage controlled for phase locking from a stable GSP locked PLL source like the G4JNT reverse DDS. An optional EME177 Oscillator heater can be added when using high turnover point crystals for better stability.
Standard and High stability Series 5th Overtone Crystals are listed in the Crystal section of the website. Divide your Output frequency by 6 for the required Crystal Frequency.