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BRIAN,
Here is a 'specific' Receive ONLY Antenna Idea to used with your new Icom IC-R75 (R-75 ![]() A Vertical Omni-Directional Antenna made from a single piece of Coax Cable for 60Mhz down to 30 MHz. First Read this Link "Coax Cable" - by Great Yarmouth Radio Club http://www.qsl.net/g3yrc/coax.htm WHAT IT IS: This is a one piece Coax Cable Antenna and Lead-in-Line for 60Mhz to 30MHz. Basically a Half-Wave-Length (1/2 WL) Vertical Dipole Antenna Cut for 60MHz with a De-Coupling Coil at its base CONSTRUCTION - HOW TO: Start with a piece of your favorite Coax Cable in a 50. 75, or 100 Foot Length. (Your Choice based on your location Requirements: Measure, Plan and Decide.) * The Radio End of the Coax Cable will have a PL-259 Plug Connected to it. * The Far-Antenna-Tip-End will have (no-connector) with the Inner-Conductor and Outer-Braid Soldered Together. * Next at the Far-Antenna-Tip-End a Small ("1 to 2") Shepherds Loop is "Formed" and 'held-in-place' with Three to Four evenly spaced Plastic Wire Ties. * A Small Section (1/2" to 1") of the Coax Cable is removed at Half a Wavelength as measured from the Far-Antenna-Tip-End. * A De-Coupling Coil is made of/with the Coax Cable at One Wavelength as measured from the Far-Antenna-Tip-End. * The De-Coupling Coil is Six Turns of Coax Cable in small 3"-4" Loops that are held together by Six evenly spaced Plastic Wire Ties. [Three to Four Clamp-On Ferrite Cores can be used instead. ] * The "Top" Antenna Element and "Bottom" Radiator/Reflector Sections are 'suspended' Vertically as a Unit from the Ground with the De-Coupling Coil at or near Ground Level. ANTENNA MEAUSREMENTS: STANDARD - RG-8/58/59 Type Coax Cable with a "Velocity Factor" of # 0.66. * Half-Wave-Length (492 * .66) divided by 60 MHz equals 5.41 Feet [5 Feet 5 Inches] * Top- Antenna Element Section = 5 Feet 5 Inches * Gap = One Inch * Bottom Radiator/Reflector Section = 5 Feet 5 Inches * Six Turn De-Coupling Coil Diameter = 3.5 Inches * Minimum Vertical Height = 11 Feet 2 Inches * Remainder of the Coax Cable is the Lead-in-Line to the Radio/Receiver. ULTRA-FOAM - RG-8/58/59 Type Coax Cable with a "Velocity Factor" of # 0.80. * Half-Wave-Length (492 * .80) divided by 60 MHz equals 6.56 Feet [6 Feet 7 Inches] * Top- Antenna Element Section = 6 Feet 7 Inches * Gap = One Inch * Bottom Radiator/Reflector Section = 6 Feet 7 Inches * Six Turn De-Coupling Coil Diameter = 4.25 Inches * Minimum Vertical Height = 13 Feet 6 Inches * Remainder of the Coax Cable is the Lead-in-Line to the Radio/Receiver. NOTE: At 30 MHz this Antenna is a Quarter-Wave-Length (1/4 WL) iane ~ RHF .. .. = = = "Brian" = = = wrote in message thlink.net... I just received my R75 today and I love it. What should I use as an antenna for above thirty MHz ? I tried my 60 ft. random wire but it seems to not work very well. Any other suggestions for a new owner of an R75 ? Brian .. |
#2
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Brian, using 130 feet of 16 gauge wire in semi-beveredge configuration, can
receive Bay Area/Sac Valley C.H.P. communications on 42.120 mhz, 42.520 mhz, 42.535 mhz, 42.599.5 mhz 42.620 mhz, and 46.610 mhz, all in f.m. mode! WA6020SWL |
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