Accession Number : ADP006878

Title :   The Utility of High Frequency Ground Wave in a Distributed Communication System,

Corporate Author : JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB

Personal Author(s) : Champion, James R.

Report Date : JUN 1991

Pagination or Media Count : 6

Abstract : The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has investigated high frequency ground wave (HFGW) communication in mountainous terrain. Using a broadband, discone antenna and 100 watts of power, communication links in the 20 to 30 MHz band of at least 50 and, in some cases, as much as 115 km have been established over mountainous paths. Links were non-line-of-sight, and immune to ionospheric fading. Digital and wide-band frequency hopping communications have been demonstrated using HFGW. The discone antenna is about 3.5 m high when assembled and can be made extremely portable. The special characteristics of the 20 to 30 MHz band coupled with the properties of the discone antenna would offer advantages to distributed communication systems in mountainous terrain. This paper presents HFGW results and discusses how this medium may be exploited in a distributed system which uses both frequency and spatial distribution. Key Words: Sky Wave Hop, Meteor Trail Reflection, and Ground Waves...

Descriptors :   *DIVERSITY RECEPTION, *RADIO LINKS, *FREQUENCY AGILITY, *GROUND WAVES(ELECTROMAGNETIC), *DISCONE ANTENNAS, *RADIO ANTIJAMMING, BROADBAND ANTENNAS, RADIO INTERCEPTION, SPREAD SPECTRUM, RADIOFREQUENCY POWER, HIGH FREQUENCY, NOISE(RADIO), RANGE(DISTANCE), SKY WAVES, MOUNTAINS, LINE OF SIGHT, RADIO RECEPTION, TERRAIN, VOICE COMMUNICATIONS, DATA LINKS, PACKETS, NEW MEXICO, IONIZATION TRAILS, METEORS, DIRECTION FINDING, IONOSPHERIC PROPAGATION, REPRINTS, SYMPOSIA.

Subject Categories : Radio Countermeasures
      Electrical and Electronic Equipment
      Radio Communications
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE