Thanks for the input Ron. The open-wire fed antenna has really captured my interest. I have not had any luck get the 90' antenna to load on 80/75 meters. My balun us switchable between 1:1 and 1:4. I just switched it to 1:1 after reading about baluns on the DX Engineering website. Perhaps that will make the difference. I have plenty of room so the 135' of wire is no problem. I could also go much larger - 260' or more. Just trying to weigh practicality with performance. Considering how well it is working so far, I may drop the collection of trap dipoles in favor of a single open-wire feed system.
Doug -- K0DXV Ron D'Eau Claire wrote: > -----Original Message----- > > I was looking for the specs for the KAT3 tuner option for the K3. Just > wondering what the tuning range is and if it will fully replace the LDG > AT-200 I'm currently using. After years of coax fed dipoles I finally > got around to experimenting with open wire fed dipoles. I'm quite > impressed with the results. I'm currently using about 90' of wire fed > dead-center with 450 ladder-line into a 1:1 current balun. The LDG > AT-200 seems to tune it just fine on everything from 40 to 10. The next > one will be 135'. Hoping the KAT3 will handle it so I can have one less > piece of equipment on the desk. > > Doug -- K0DXV > Clark, CO > > ------------------------- > > I don't know the LDG so I can't answer your question about the matching > range but I can say that your 90 foot wire will work as well as a 130 foot > wire on 80 meters. Crunching a few numbers, the "loss" caused by the > shortening is less than 0.2 dB. Indeed, you'll find virtually no additional > penalty operating it on 160 meters at that length. > > If the tuner won't handle some frequencies, adjust the length of your > antenna (or feed line if that is easier). You should be able to find a > length that the tuner can match on all the bands without significant > penalty, at least on 3.5 MHz or higher. > > The impedance gets quite low when the antenna gets down near 1/4 wavelength > or less and might exceed the KAT3's range. Assuming a height of 40 feet, the > impedance at the center of a 90 foot wire at 3.5 MHz is about 13-j600 ohms > while at 1.8 MHz it drops down to only about 0.6-j1800 ohms. The feeder will > tend to raise that impedance, assuming it isn't more than 1/4 wavelength > long. > > Ron AC7AC > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
