It is easy to build and works really well. 'Antenna' should be connected through a tuned circuit, or some sort of preselector. I have used 680 ohm for R9, and JFET MPF102.
The circuit board. The red coax is IF output that goes to the IF amplifier. The blue coax is VFO input. The coils are the voltage tuned preselector using BB112 varicaps.