Wayne, my favorite go to band has been 17 meters. I originally did Ped mobile with the FT817 and since there was no specific antenna, portable for that band at the time I used a Maldol AH-c14 with one length at the tip shortened dragging an 11' counterpoise. It is what I now use for the KX2. For the heck of it, I even tuned it on 40 with good success, didn't try working on 40 just found it interesting that it loaded at 1.2: with the fully extended whip and the 11' counterpoise.
73, Bill K9YEQ -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Wayne Burdick Sent: Sunday, February 19, 2017 2:55 PM To: Elecraft Reflector <[email protected]> Cc: [email protected] Subject: [Elecraft] MFJ 20-meter whip on 17 and 15 meters with the KX2 (or KX3) Hi all, Today I was operating pedestrian mobile in the ARRL DX contest with just the MFJ1820T 20 meter whip. This 4 foot-long whip is very narrow banded, which isn't a problem over the full 20 meter band as long as you have an ATU available - the KXAT2 in the case of today's KX2 excursion. (Note: You also need a ground counterpoise. 13 feet is about the right length.) When trying to use this whip on other bands, in a pinch, it can be tough on the ATU, given the sharp resonance of the antenna. But I realized I hadn't tried shortening the telescoping part when operating on frequencies above the target band. It turns out that, at least in my case, the ATU could match to 1:1 on 17 meters by collapsing 2 lower sections. On 15 meters, I could get a 1:1 match by collapsing 5 lower sections. While this is certainly a compromise in terms of radiation efficiency, it does make the transmitter happy, allowing the use of full power. I didn't do any far-field tests to compare the shortened whip at 1:1 to the full length of the whip at much higher SWR, but for receive purposes, it was about a wash. As a bonus, there's less metal waving around in the air. This can be handy when you're walking, especially in a residential area with a lot of "Neighborhood Watch" signs proudly displayed :) 73, Wayne N6KR ______________________________________________________________ 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 Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
