RF-Radio Frequency

High Quality FM BUG

This project requires a high degree of soldering. It uses surface-mount resistors, capacitors transistors and diodes. It can only be assembled on the PC board supplied in the kit as the Latching Circuit is already soldered to the board and the project will not work with substitute components. The Infinity Bug connects across the phone line and takes very little current as most of the circuit is not active when in the “waiting” state. This is called “leeching” and the Infinity Bug is a leech device as it gets its operating current from the phone line. Some phone systems detect as little as 0.5mA and if more than 1mA is drawn from the line, it remains engaged. ..
Source: http://www.talkingelectronics.com/projects/infinitybug/infinitybug-p1.html

5/8 Wave 3.4dB FM Broadcast Antenna

This is probably the most popular FM broadcast antenna we sell. Why? Let’s start with the proven omnidirectional ground plane design, clean rugged construction, and how about easy mounting? The 5/8 wave design keeps your signal low to the horizon and not uselessly radiating up into space – great if your listeners are on the space shuttle, but the pits for the folks out at the edge of town! Imagine a donut shaped pattern of signal radiating from your antenna. For the most range out to the horizon, we need to squish that pattern flatter to squeeze more signal out to the horizon – and that’s exactly what this antenna does! Plus it has 3.4 dB gain, which effectively doubles your transmit power over a unity gain antenna! The FMA200 is super easy to assemble and mounts to any standard antenna mast….Read more

400mW fm bug transmitter circuit

Power supply: 12-14 V stab., 100 mA. RF power: 400 mW. Impedance: 50-75 ohm. Frequency range: 87,5-108 MHz. Modulation: wideband FM. Connect the 6 V / 0,1 A bulb to the output and use R1 to tune the right frequency. Maybe you might stretch coils of the L1. Then use C14 and C15 to adjust the highest power (the highest light of the bulb). Then you can connect antenna and audio signal. Adjust R2 until the audio sounds as loud as the other stations. With good antenna (dipole placed outdoor and high) the transmitter has very good coverage range about 500 meters, the maximal coverage range is up to 4 km…Read more

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