| Parts
List: |
| Component: |
Value: |
Datasheet: |
Qty: |
| Resistor |
47K |
Not Available |
02 |
| Resistor |
10K |
Not Available |
01 |
| Resistor |
220 |
Not Available |
01 |
| Capacitor |
1nF |
Not Available |
01 |
| Capacitor |
1uF |
Not Available |
01 |
| Capacitor |
6.8pF |
Not Available |
01 |
| Capacitor |
1.8pF |
Not Available |
01 |
| Microphone |
Regular |
Not Available |
01 |
| Antenna |
~10" wire |
Not Available |
01 |
| Transistor |
BC547 |
Not Available |
01 |
- The coil is 1/4" (4mm) diameter
& wound on a drill bit. A simple piece of insulated wire about 2 feet (60cm) was fine
for the antenna, and is coo a 1-turn tapping of the coil. Use tinned copper wire for the
tuning coil and not the enameled wire for kids. It is much easier to solder the antenna
without destroying the coil trying to remove the enamel. If you also wish to use it from
the headphone socket of an HF rig then delete the first 47K resistor & reverse the 1uf
capacitor. The circuit shown is for an Electret condenser microphone. The transmitter may
be received by any VHF FM radio, but the pocket radio I use in the house was free with
WEETABIX boxtops a few years ago. It should have a range of at least 250 feet (75meters)
but increase the 200R emitter resistor to 1K to reduce the range)
