FAX5 coupler antenna requirements

​Furuno weather fax systems all require an antenna of appropriate length. This includes either a long wire or backstay type. Alternately, a FAX5 antenna coupler can be used which will receive both 80kHz – 25mHz weather fax and 490 or 518 kHz NAVTEX (if installed) frequencies. The FAX5 coupler requires a 2.6 meter (~ 8-feet) fiberglass or stainless steel whip antenna for maximum receiving range. Note that a standard 4-foot antenna is too short for proper operations and will cause poor receive sensitivity.