RECEIVER ASSEMBLY:
1. Install the RCA antenna jack, J1. Solder all four points.
2. Install C5, a .01µF ceramic disc signal coupling capacitor . This capacitor brings the signal up to the front of the PC board. Notice the long PC trace from J1 through C5 to R1.
3. Install potentiometer R1, the RF gain control. Insert it into the PC board so that it seats firmly and is straight and even. Solder the three pins and the two mounting tabs.
4. Examine inductor L1. Look at the bottom side and you’ll see a small silver and brown tubular part nested within the black plastic base. This is actually a ceramic tubular capacitor! It resonates with the tuned circuit for for 10.7 MHz. This is the wrong frequency for our purposes so we’ll simply remove it and add our own external capacitor (C13). Removing the tubular capacitor is not as hard as you might expect, simply crush it completely with a small screwdriver or knife. Omitting this step will prevent L1 from peaking on 20 meter signals.
5. Install L1(marked
6. Install C13, a 27pF ceramic disc capacitor (marked 27 or 27K).
7. Install U1, the SA602 IC
The parts we have put in so far bring the signal from the antenna jack up to the RF Gain control (actually the RF attenuator) and to a tuned circuit composed of L1 and C13. Inductor L1 allows us to match and tune the 20 meter band signals to the SA602’s input.
8. Install C6, .01µF. This capacitor bypasses pin 2 of the SA602 to ground. Bypass means to provide a nice low impedance (impedance means AC resistance) path to ground.
9. Install R4, 270 ohms
10. Install D2, 6.2 volt Zener diode. This is the smaller of the two diodes and has a painted glass body. This diode acts as a voltage regulator by keeping the voltage across it constant.
11. Install C10, a