1. Grant Hodgson G8UBN A new AO-40 K-band Downconverter

2. Grant Hodgson G8UBN A new AO-40 K-band Downconverter Topics presented :- n Conventional Downconverter Design n New dual-injection design with new components n New Synthesised Local Oscillator

3. A new AO-40 K-band Downconverter

4. Proven design Image frequency is very close to wanted frequency - Therefore a narrow waveguide filter must be used Which requires adjusting and aligning Local Oscillator multiplier (x4 or x5) requires aligning Conventional Local Oscillator also requires aligning Conventional 24GHz Downconverter

5. A new AO-40 K-band Downconverter Conventional 24GHz Downconverter Photo courtesy of Mike, N1JEZ

6. A new AO-40 K-band Downconverter 24GHz Waveguide Filter Photo courtesy of Howard, G6LVB

7. A new AO-40 K-band Downconverter Be self-contained - no external LO etc. No-tune design Low frequency drift with temperature Modular design - interchange various system components (LO, LNA etc) Allow reception of terrestrial Dx at 24192MHz as well as AO-40 K-band downlink (24048MHz) Use new components that will not become obsolete in less than 5 -10 years Encourage experimentation at microwave frequencies! New 24GHz Downconverter - design objectives

8. A new AO-40 K-band Downconverter

10. Harmonic suppression of HMC204 doubler

11. A new AO-40 K-band Downconverter Brief overview - image response of mixers

12. A new AO-40 K-band Downconverter

14. Difficult choice at 24GHz Various options, but probably :- Separate (external) LNA Duroid, Taconic or Similar Main PCB on std. FR4 fibreglass PCB

15. A new AO-40 K-band Downconverter Most of the design objectives have been met Next step is circuit design and prototyping Waveguide image filter has been eliminated True no-tune design Operation on K-band should become easier, whilst still leaving lots of room for investigation and experimentation Summary