Accession Number:

ADA127040

Title:

Wideband HF Channel Prober: System Description.

Descriptive Note:

Interim rept. Jun 78-Jun 82,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC TRANSMISSION TECHNOLOGY BRANCH

Report Date:

1983-03-09

Pagination or Media Count:

47.0

Abstract:

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.

Subject Categories:

  • Radiofrequency Wave Propagation
  • Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE