a more capable tuner - see AA5TB's Usually any wire length that is non resonant, like those shown above, will work with the 4:1 ratio. results. PDF shortened multi-band End-Fed Half Wave (EFHW) antenna for 80-10m Tweak the antenna length if necessary and then maybe adjust the turns ratio again. these are the worst lengths and you want to be as far from colored 40-30-20-17. Meet 'Balun One Nine', a small, cost-effective balun. Two pieces of 14 gauge enameled wire (e.g., Thermalese), one short piece (about 1 foot in length) and one long piece (about 7 feet in length). is that for a given ham band there are min and max frequencies which This transformer converts the impedance at the end . The Short Answer Would Be That an UnUn Is a UN balanced to UN balancedmatching transformer. Jack, VE3EED, used center frequencies of thebands described in the article above, and I thought it would be nice to use band edges. EFHW unun Resonant Long Wire 49:1 Transformer With BNC or SO-239Random Wire Antenna Lengths - University of Delaware Quantity: Sold individually. You also >> When used with the stated lengths shown in thetable below, the 9:1 ratio will Based on the success of our model 4932, this 5kWconfigurationisalso perfect for matching both long and short length wire antennas for multiband use. Random wire lengths you should and should not use! 7 0 obj <>
/Resources << Hopefully these random wire length calculations will help us all make this "easy" antenna work better! He had heard good things about 'Balun Designs' so he recommended you. Ham Radio News! ?7{*. Power Handling (CW/SSB): 100 W/200 W Enclosure Width: 2.500 in. Mike ab3ap, Editors note: Many thanks to Jack, VE3EDD (SK)and Mike, AB3APfor sharing their math and computerskills with us. this I have used the 49.2 ft (15 Meter) length of wire on vacation with both automatic tuners and an MFJ Model 16010 tuner with good results for 40, 20, 17, and 15 Meter operation. all US ham bands. %PDF-1.7
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