I've had seemingly good results with my KX1 on 20, 30, and 40 just using the 25 ft wire thrown into a tree and a 16 ft counterpoise along the ground. The KXAT1 found useable matches every time. It seems like I remember doing OK on 80 meters too, but that may have been into my 6BTV vertical at home.
If I'm out during the day and happy with 20 meters only, I use an End-Fedz 20 meter half wave antenna and no counterpoise, and it works well for me with the KXAT1 turned off. Good luck! Chip On Fri, May 13, 2011 at 1:17 PM, Don Wilhelm <[email protected]> wrote: > Bob, > > Actually, a properly functioning KX1 has an MDS of better than -130 dBm, > so it actually is a sensitive receiver. > > Some like the Carolina Windom, but I don't like any unbalanced antennas, > and have a high preference for center fed antennas, they are easier to > tame, and if the feedline leaves the antenna at right angles from the > center, seldom do "RF-in-the-shack" problems emerge. > > The KXAT1 has a more limited range on 80 meters than the other bands > just because the total inductance and capacitance is limited - only 3 > choices of each. > > I would suggest a trap antenna with traps for 40 and 20 meters. Feed it > with balanced feedline cut a half wavelength (or multiple) on 80 meters > - the tuner should be able to match it on 30 meters and the half > wavelength of feedline on 80 meters should present a feedpoint impedance > close to that at the antenna center (50 to 75 ohms) for 80, 40, and 20 > (assuming the traps are used). > I have not actually built such an antenna, but the theory says it should > work just fine. Keep the balanced feedline supported along its entire > length and don't forget that there is a velocity factor to consider when > determining a half wavelength - if you cannot do that, add a trap for 30 > meters and feed it with any length of coax. Coaxial traps are not > difficult to build, and for QRP use, can even use RG174 on a piece of > 1/2 inch PVC for a form. Doug DeMaw (SK) W1FB had information on > building traps like that in QST a very long time ago (try in the > 1980s). Also see the W1FB Antenna Notebook and/or the article in QST > for Decenber 1984 page 37 by N4UU. Gary o'Neil N3GO also has some good > information about coaxial traps on the web (use Google). > > I realize that a 135 foot long antenna is not "easy to deploy", so I > would suggest an alternative - build a coax fed trap antenna for 40, 30 > and 20 meters (traps for 30 and 20), and carry along 2 33 foot lengths > of wire - insulators on one end and an alligator clip on the other - > when you want to operate 80 meters, add the wires to each end of the > radiator. You could carry that concept a bit further, and build the > antenna for 20 meters with no traps and then add a set wires for use on > 30 meters, another set of wires for 40, and yet another set for 80. > clip on the wires for whichever band you want to operate. > > That is my nickel's worth. > > 73, > Don W3FPR > > On 5/13/2011 1:31 PM, AB5N wrote: > > Hi Guys- > > > > Well, I'm in week two of enjoyment with my new KX-1. I did have a few > > problems in assembling, but > > that is history. > > > > This little rig has a simple receiver which has only half the sensitivity > of > > a usual radio. As well, we are dealing > > with 3-4 watts TX out max. We have to have an excellent antenna. I've > tried > > the suggested 25 ft. long wire > > with radials. Ah, it's not good enough. I even got some strange > RX-feedback > > internally at some frequencies using it. I believe the criteria for an > > excellent antenna will be as follows: > > > > 1. Will match up well using the internal tuner on all four bands. > > > > 2. Has enough metal in the air to provide adequate microvolts to the RX - > to > > make it function well without > > being overloaded. > > > > 3. Provides some gain - or at least a clean predictable pattern > > > > 4. Is light, compact and easy to deploy. > > > > My inkling is that a normal Carolina Windom may be the thing. I'll work > on > > developing a micro-QRP version. > > > > What doesn't work? > > > > Classic G5RV (102 Ft) - will not load on any band with tuner. > > Offset-Zepp fed with Coax (75'x25') > > > > What say guys? Anybody have superb luck with an antenna yet? > > > > Bob-AB5N > > > ______________________________________________________________ > 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 > ______________________________________________________________ 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
