Zur deutschen Seite

Monitor Experiment

Fabrication Responsibility:
Andras Gschwindt, HA5WH
Peter Bakki, HG5CQC
Sandor Blasko, HG5CRS
Average Power Dissipation:
1 Watt


The ionosphere MONITOR experiment is designed for passive sounding the space above the ionosphere in the HF band between 0.5 and 30 MHz. The analog part of the MONITOR measures the electromagnetic field density in the mentioned band. The receiver consists of two mixers. The first IF is 45 MHz, the second is 455 kHz, both with a bandwidth of 7.5 kHz. A linear IF amplifier stage measures the received signal strength in 80 dB dynamic range. AM demodulation of the signal is also possible. The system is controlled by a built-in computer which command the receiver and store the measured data. The CPU is a Motorola 68HC11 microcontroller. The system can sweep in the whole frequency range with step sizes of 5 kHz and 9 kHz or repeat the measurements on one selected frequency.
Last updated: Jan 5, 1996
by Ralf Zimmermann, DL1FDT