Facsimile transmission via HF radio

The authors examine the feasibility of transmitting facsimile (FAX) over radio voice-channels using existing machines and existing radio installations. CCITT Groups 1, 2, and 3 FAX were tested on simulated high-frequency (HF) channels using the US government's HF simulator at Ft. Monmouth, NJ. Tests included both the premessage exchange and the message portion of the FAX transmission. Test results show that the FAX integral wire-line model used for Group 3 operation does not work well on realistic, long-haul, HF channels even at the minimum fallback rate of 2400 b/s. Group 2 FAX also fails for most of the cases simulated. Group 1 FAX produces documents on most simulated channels although the quality of the document degrades as the impairments become severe. The degraded documents, however, are usable in most cases.<
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