![]() ![]() a severe impedance mismatch exists at the antenna feedpoint. Connecting the coaxial feedline resonates the antenna system just as connecting a properly tuned open-wire feeder resonates the antenna system.Ĭonsider a 50 ohm 1/2WL resonant center-fed dipole fed with 1/2WL of open-wire line. Note: with the feedline disconnected, a 1/2WL center-fed dipole is non-resonant. The well-respected Extended Double Zepp is an example of a non-resonant antenna that will outperform a resonant 1/2WL center-fed dipole in the dipole's favored direction. *system resonance* is established with an apparent 100 ohm source and 100 ohm load thus ensuring maximum transfer of available power. If we feed the antenna with open-wire line and adjust the antenna tuner in the shack such that the impedance looking back down the transmission line towards the source is 100-j200 ohms, the reactance is neutralized, i.e. Let's assume we have a non-resonant antenna with a feedpoint impedance of 100+j200 ohms. Conjugately matched *systems* ARE resonant. It doesn't matter if the antenna by itself is resonant or not. If the antenna system is a low-loss system, the effect of that Z0-match in the shack is a near-conjugate match at the antenna feedpoint which guarantees maximum transfer of available power to the antenna. An antenna tuner establishes a Z0-match to 50 ohms, commonly called "making the transmitter happy". > people do not understand that it cannot make a non resonant antennaĪpparently, some people don't understand the maximum power transfer theorem. > The regular MFJ 949 series tuner was usually employed - although most On Wednesday, Novem5:50:28 PM UTC-6, Channel Jumper wrote: Some good web pages to look at are K3CC, K0BG, KC9AOP There are lot's of nets with real hams up on 80 and 160 meters - if youĬan find them that knows a little about this stuff. Lot's of research and to listen before transmitting. One point I always make with new hams and inexperienced hams is to do Want to buy the best possible antenna's for the money. Having a good transceiver to use, and not wanting to damage it - you Not everything that a person with a resonant antenna hears. The bottom line is - even if they claim they can work everything they People do not understand that it cannot make a non resonant antenna The regular MFJ 949 series tuner was usually employed - although most Then after world war two - coax became available and people bought it We used a Johnson Matchbox with a couple of coils and life was good. IN the early days of amateur radio, there was no coaxial cable - hence The key is to only use resonant antenna's. Thank you in advance to all who choose to tackle this Since I really am asking questions I hope there is already a consensusĪnswer as I would not be able to sort out the various sides of anyĭebate. The SO239 connector by using say a banana plug. Not have obvious balanced feed line terminals would I connect aīalanced feed line to the ground terminal and the the center pin of Two shields at the transceiver end? Further since the FT-1000 does When you use the two parallel coax leads do you ground and/or bond the The two pieces of coax in parallel that I have read of elsewhere? So is a balun a good solution to this challenge or should I resort to I would guess that I need a balun but which type is a I used an IcomĪH4 antenna coupler with my FT-857D on this antenna with very good Short say twenty feet coaxial feeder from the radio. Tuner, that I'm hoping to use, I need to ask what the best way is toĬouple the window line that feeds my folded dipole antenna into a Thanks to the generosity of a fellow radio club member I now have the
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