| 1.5 V FM bug v2 |
A little fm bug on 1.5 V, of a bit better construction. |
| Antenna BIG-J for 145 MHz (2m) |
Big J antenna, gains of J antennas and a few more pieces of information. |
| Antenna J for 440 MHz (70cm) |
J antenna, very simple, for 440 MHz (70cm). |
| Antenna for 7 to 30 MHz |
Antenna for 7 to 30 MHz. |
| FM bug v2 |
FM bug. |
| Frequency meter |
Frequency meter using PC. |
| Linear power amplifier for 433 MHz |
Linear power amplifier for 433 MHz with two transistors. |
| Small bug on 1.5V battery |
Stable and very small transmitter, 500 hours with AA battery. |
| Spy bug in a pen |
Small and narrowed FM transmitter at 12V. |
| Stronger bug |
Stronger bug and simple to build. |
| Transmitter and receiver for data on 433 MHz |
Schematics of a transmitter and a receiver for data communication (suitable for alarms) on 433 MHz. |
