project was designed to convert the IF frequency of a modern radio to
the IF frequency of the Heathkit Scanalyzer.
The original SB-620 came with a number of different IF coils, you built
the unit with the proper coil for the radio used at the time. 30
years later, most of the old additional coils are long lost, and now,
converting the SB-620 to a new IF is no longer practical.
This project was built to convert the IF of the ICOM 706MKIIG at
9.0115 MHz to the present IF of my SB-620 at 3.180 MHz
Building blocks are:
- 5.8 or 12.2 MHz local oscillator
- input from ICOM at 9.0115 MHz
- double balanced diode mixer
- bandpass filter at 3.180 MHz
- (also a small rf amp to boost the
ICOM IF signal to usable levels,
this section is not shown here).
The project was layed out with EAGLE CAD software, The PCB was
etched and drilled.
Silkscreened using a laserprinter, acetate sheet and an iron.