KX-1 antenna matching
Posted by
Rick Dwight on
Jun 09, 2017; 10:23pm
URL: http://elecraft.85.s1.nabble.com/KX-1-antenna-matching-tp7631522.html
Stan,
I have used a kx 1 for thousands of QSO’s many in the field on 40, 30, and 20 meters. My usual field antenna is a 26 ft piece of wire and one or two 17 counterpoise wires. If the counterpoise (radial) wires are laying directly on the ground, usually I get a very good match on all 3 bands. If part or all of the counterpoise/radial wire is elevated, then sometimes I clip on an extension of about 8 feet to get a better match if the SWR is higher than about 2:1 (probably only necessary on 40 meters sometimes). Occasionally for 40 meter elevated counterpoise operation I have even used a single 34 ft counterpoise wire if I happen to have one available….not likely when backpacking. I would just use your 16 or 17 ft counterpoise for 20 meters…it might improve your 1.6:1 SWR, however I still have my original PA transistor and have often operated with SWR’s around 2:1 or higher, however my goal is to try not to exceed about 2:1. Usually I can get SWR down somewhere between 1:1 and and perhaps 1.9:1 (just a guess) on 40 meters, and often about the same or even slightly better on 20 and 30 meters. I always carry a 8 ft piece of wire with a big clip on the end. Often clipping it to a metal picnic table, guard rail, chain link fence, or car body either instead of a radial, or in addition to one and get satisfactory performance. If I use an elevated counterpoise…then I clip the 8 ft wire onto the end of my 17 ft counterpoise for better matching on 40 and possibly 30 meters. I see no reason to just use a 8 ft counterpoise or radial wire for 20, a 16 or 17 wire should be better on all the bands. Occasionally I lay down two 17 ft radial wires on the ground if I have them and there is room. Some of my attempts at modeling showed slightly improved performance. If I have a preferred direction I often lay them down in roughly that quadrant. The theory is it may slightly help in that direction, but more important it may eliminate a very slight null opposite to the desired direction. This is my unproved theory only since it would be nearly impossible to measure something like a dB or so.
This is usually the only antenna I carry for backpacking, or travel around the US or Europe. Something like a linked dipole (usually set up as an inverted V) will often perform significantly better, however I much prefer something like the 26 ft wire….5 minutes to set up and lots of time to operate vs. an hour set up and less operating time.
Rick KL7CW Palmer, Alaska
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