Wideband HF Channel Prober: System Description

The high-frequency, extended-line-of-sight (HF ELOS) channel, which is planned as the primary intra-task-force communication link, is a multimodal channel involving modes of widely disparate characteristics. The surface-wave mode is relatively broadband, while the sky-wave modes are substantially mo...

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Bibliographic Details
Main Authors: Wagner, Leonard S, Goldstein, Joseph A, Chapman, Eather A
Format: Report
Language:English
Subjects:
BROADBAND
CHANNEL PROBERS
CHANNELS
CORRELATION TECHNIQUES
DATA BASES
DISPERSIONS
ENVIRONMENTS
HIGH POWER
IONOSONDES
IONOSPHERE
IONOSPHERIC PROPAGATION
LINE OF SIGHT
MONITORS
MULTIMODE
PE61153N
PROCESSING
PULSES
Radio Communications
RADIO RECEIVERS
RADIO TRANSMITTERS
RADIOFREQUENCY
Radiofrequency Wave Propagation
RADIOSONDES
REVERBERATION
SALINITY
SEA WATER
SIGNALS
SOUNDING
SURFACE WAVES
TIME
TRANSMITTERS
VELOCITY
WIDEBAND COMMUNICATION
WU0141
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Description
Summary:The high-frequency, extended-line-of-sight (HF ELOS) channel, which is planned as the primary intra-task-force communication link, is a multimodal channel involving modes of widely disparate characteristics. The surface-wave mode is relatively broadband, while the sky-wave modes are substantially more limited in bandwidth because of the inherently dispersive character of the ionospheric propagation medium. Environmental factors such as sea state, seawater temperature and salinity, atmospheric-refractive-index vertical profile, and ionospheric conditions all exercise strong influences over the link characteristics. A definitive data base from which to infer the broadband signaling characteristics of the channel is not presently available. The Wideband HF Channel Prober is a very short pulse (1-microsec) HF radio sounder with the necessary sensitivity, time resolution, and processing speed to monitor and record the details of the pulse response of the channel. To exploit fully the average-power capabilities of most high-power transmitters, a coded PM sequence is transmitted rather than a single pulse. The period of the PN sequence is designed to be comparable with the expected reverberation time of the channel. Correlation processing in the receiver results in a processing of gain of the order of 34 dB.