Micro Beacon 144 MHZ

It is a low power modulated VHF beacon. She beeps. The scheme consists of a LF oscillator and a VHF oscillator. The power supply of the beacon is under 9 volts, but for a long duration a battery is recommended.

The 144 Mhz beacon consists of two parts:

700Hz multivibrator provides audio modulation and is turned on/off by a 2Hz multivibrator.
A high frequency generator delivering about 30mW HF

This diagram of the HF generator is inspired by the assembly of F4DXU, The oscillator vk6fh

The HF generator consists of a quartz which drives the transistor on 24 MHz which resonates on the harmonic 6 = 144 MHz. The oscillator is modulated in FM, AM and USB at the same time.

CV 1 in series with the 48 MHz crystal, its capacitance variation causes the quartz frequency to deviate by a few KHz, for a frequency choice of 144 MHz. CV2 should be set to 144 MHz for maximum power.

This 144 MHz beacon can be used for Fox Hunting.