Micro beacon " Froggie"

This radio transmitter is just for fun. It sounds like a frog when it gives short signals on 3699kHz LSB every second or two.

Transmitting power is very small, less than 1mW. Useful tranmission distance is less than 50m.

Power consumption is very low. One LR20 battery (large 1.5V) can last more than a year.

Froggie can be used as a frequency calibrator as well because frequency stability is very good.

I believe any frequency on 80m band is possible by just installing a suitable xtal.

Other band may need component changes.

Antenna requirements depend on needed distance. Few meters of wire is good for 30m distance.

Short dipole extend the range up to 100m.

The circuit itsellf is a crystal controlled clap oscillator. At the same time is acts as a 0.5Hz blocking oscillator

giving the pulsating froggie sound.

Have fun.

18.10.2010

Pekka, OH1TV