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Off-Center Fed (Windom) HF Wire Antenna for ERC Frequency Bands Richard Wheeler (AI6RW) or Multiband Antenna Design Values Ai6rw Balun & 33% & 40% Systems 20% & 10% Systems Ai6rw Balun Kit Parts
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Multiband Antenna Design Values
Shunt L Length1 Length2 Series C T-Ratio Ai6rw Balun 50 Ohm Coax Transceiver or 2/25/2009
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AI6RW Balun 33% & 40% System 33% - 100 pF 40% - 150 pF Cat5 Capacitor
33% - 46’ antenna wire 40% - 55’ antenna wire Orange/White Blue core is: ur = 800 FT or or Green/White 200 Ohms 33% - 92’ antenna wire 40% - 82’ antenna wire Orange Green Brown A B Orange White Brown White Orange Green White Blue AI6RW 4:1 Balun Cat5 Capacitor Green Blue White 33% pF 40% pF Cat5 Capacitor Four 100 Ohm twisted pair lines Evenly separate windings Blue Core 200:50 Ohm Transformer Design: 4.5 foot length of Cat5 cable. 5 turns through 3 Fair-Rite cores. ur = 500,800,1500 Use either: or or *NOTE: Can also Use 5 turns of RG58/U RG303 RG62/U (teflon) coaxial cable. *NOTE: The last turn slides better by wetting the end with a little soap 12 Turns Cat5 capacitor: C = 4.8 pF/in Connect 4 solid colors for A Connect 4 white colors for B 100 pF = 21 inches 150 pF = 31 inches 270 pF = 56 inches 320 pF = 67 inches *NOTE: Wrap length of wire to form coil less than 2 inches in diameter. Tape. ***Note: Turns enter the core from opposite directions. 16” long Green Pair Orange Pair Note: Internet distributors for ferrite cores: Brown Pair Blue Pair AI6RW Balun Orange/Green *NOTE: Excellent reference for design of baluns: “A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing“ By Jim Brown K9YC Orange White/Green White Orange White/Green White Orange/Green 50 Ohm coax to transceiver 50 Ohm coax to transceiver 2/2/2011 or
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10% System 20% System 320 pF 150 pF Cat5 Cat5 Cap Cap AI6RW Balun
124’ antenna wire 28’ antenna wire 110’ antenna wire Yellow Core 2:1 tapped 40 uH inductor (200:50 Ohms) 16” long Yellow Core 2:1 tapped 40 uH inductor (200:50 Ohms) Yellow Core 12 Turns Orange 16” long 3:1 tapped 50 uH inductor (450:50 Ohms) 12 Turns Orange White Orange 8 Turns each Side by side 320 pF Cat5 Cap A A Orange White Orange White Orange 150 pF Cat5 Cap Orange B Yellow core is: Ur = 125 FT or Orange Green White Orange White B Green Green Green White AI6RW Balun Cat5 Length to balun start = 10 feet This length is 10% of antenna radiator Green White Orange White 50 Ohm coax to transceiver Green White Orange Orange White Orange 50 Ohm coax to transceiver Green Green 2/2/2011 or
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OLD DESIGN 10% System 20% System 320 pF 270 pF AI6RW Balun
20% & 10% Systems Old Design 124’ antenna wire 28’ antenna wire 110’ antenna wire OLD DESIGN Yellow Core Green 2:1 tapped 50 uH inductor (200:50 Ohms) 11” length Blue Yellow Core 12 Turns 16” long 3:1 tapped 50 uH inductor (450:50 Ohms) Green White Blue White Orange 8 Turns each Side by side 320 pF A A Orange White Orange White Orange 270 pF B Yellow core is: Ur = 125 FT or B Green Blue ***Note: Turns enter the core from same direction. Blue White Green White 5 turns RG58/U Coax RG58/U Coax Length to balun start = 10 feet Outer shield of coax is part of the antenna AI6RW Balun 50 Ohm coax to transceiver Orange White Orange 50 Ohm coax to transceiver 2/25/2009 or
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Ai6rw Balun Kit Parts old design
Assembly Instructions BNC Solder Connector 180 pF capacitor 6000 volts 100 pF capacitor 6000 volts OLD DESIGN 3 ea Fair-Rite cores. Ur = 500,800,1500 Use either: or or Yellow core is: Ur = 125 FT or 2 each Cat5 cable Six foot lengths Blue core is: Ur = 800 FT or or 2/25/2009
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Ai6rw Balun Kit Parts Assembly Instructions UHF Solder Connector
3 ea Fair-Rite cores. Ur = 500,800,1500 Use either: or or Yellow core is: Ur = 125 FT or Cat5 cable 20 foot length Blue core is: Ur = 800 FT or or 2/2/2011
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