Estimation of the availability of data modems on oblique high latitude HF paths

• Published in: 7th International Conference on High Frequency Radio Systems and Techniques pp. 159 - 163
• Main Authors: Angling, M.J, Cannon, P.S, Davies, N.C, Arthur, P.C
• Format: Conference Proceeding
• Language: English
• Published: London IEE 1997
• Subjects: Applied sciences; Exact sciences and technology; Modems; Propagation through the atmosphere; Radio links and equipment; Radiocommunications; Radiowave propagation; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); oblique high latitude HF paths; modems; low power waveforms; DAMSON; high frequency communication systems; frequency spread characteristics; multipath spread; narrow band HF channel; pulse compression waveforms; Doppler effect; Doppler shift; scattering function measurement; 2 to 30 MHz; beyond line of sight communication systems; telecommunication network reliability; transmitter power; propagation environment; digital signal processing; signalling waveform; time of flight; Doppler spread; received signal to noise ratio; ionospheric electromagnetic wave propagation; multipath channels; 3 kHz; electromagnetic wave scattering; data modems; pulse compression; propagation path; signal strength; channel sounder; HF radio propagation; system performance; Doppler and multipath sounding network; time spread characteristics; antenna gain
• ISBN: 0852966881; 9780852966884
• ISSN: 0537-9989
• DOI: 10.1049/cp:19970781

The performance of beyond line-of-sight (BLOS) high frequency (HF) communication systems is dependent on the match between the system and the propagation environment. Antenna gain and transmitter power, and consequently the received signal to noise ratio (CNR), are very important in this respect. However, the match between the signalling waveform and the time and frequency spread characteristics of the propagation path often deserves equal or greater attention. This paper is based on the analysis of data collected by a channel sounder known as DAMSON (Doppler And Multipath SOunding Network) which can characterise the narrow band HF channel (3 kHz) by measuring its scattering function. The system uses low power, pulse compression waveforms and makes extensive use of digital signal processing techniques in order to measure, in real time, the signal time of flight, multipath spread, Doppler spread and shift, and signal strength over communications paths. The DAMSON system operates from remote sites on pre-selected frequencies ranging from 2 to 30 MHz.