Step 8: Design of the Microphone Transmitter Kit
PCB
ONE 500KOhm Trimmer Pot
TWO NPN 9018 Transistors
ONE NPN 9014 Transistor
ONE 4.5 turn Inductor (4T5)
TWO 5.5 turn Inductors (5T5)
ONE Electret Microphone
ONE 1M Resistor (BrownBlackGreen)
TWO 22K Resistors (RedRedOrange)
FOUR 33ohm Resistors (OrangeOrangeBlack)
THREE 2.2K (2K2) Resistors (RedRedRed)
ONE 33uF Electrolytic Cap
FOUR 30pF Ceramic Capacitors “30”
FOUR 100nF Ceramic Capacitors “104”
ONE 10nF Ceramic Capacitor “103”
TWO 680pF Ceramic Capacitor “681”
TWO 10pF Ceramic Capacitor “10”
Antenna Wire
9V Battery Clip
Header Pins (break to 2 and 3 pins)
Note that the three transistors, the microphone, and the one electrolytic capacitor must be oriented as shown on
the PCB silkscreen. The inductors and ceramic capacitors are not polarized. While the values and types are not
interchangeable, each one can be inserted in either orientation.
If you are new t o soldering:
If you are new t o soldering: There are a lot of great guides and videos online about soldering. Here is one
example. If you feel that you need additional assistance, try to nd a local makers group or hacker space in your
area. Also, amateur radio clubs are always excellent sources of electronics experience.
HackerBox 0034: SubGHz: Page 6
