HI Barry, I expect your antenna is ok, or at least not mislabeled.... I don't have a 20 meter version to measure, but I do have the 17 meter version. It works fine on 17 with the KX3 with a drag wire or radial. On an AA30, with no counterpoise, it repeatedly measures resonance sharply at about 23.4 mHz. But that's an all plastic analyzer case. I've seen it lower on my old MFJ with the metal case, but still not resonant without any counterpoise. Based on that I'd guess your 17 meter resonance is a coincidence, and the result of measuring it as you did, not a mislabeling issue. I've done a lot of work over the last year with analyzers and small whips since Wayne started looking for the Holy Grail mini-antenna, and I can assure you that if you're looking for reliable low SWR and resonance, you should only do the experiment as you intend to use the antenna. With the KX3 as a handheld this meant holding the radio with mounted antenna the way you plan to in the field, with a drag wire or radial of the length you plan to use, and over the type of ground you expect, strung out as you plan to sit, stand or walk. I ended up going with a single 12 in section of Buddistick mast on a bracket, a mini or regular coil, and a standard whip. This is surprisingly light and breaks down to 12 inches. With the regular coil and a 13 foot drag line I can usually manage to do 10 - 30 meters (sadly will NOT hit 40) with preset taps on the coil, sitting on a bench on average terrain without having to use the tuner. But change anything and it's up for grabs again, hence having a tappable coil in the filed is a blessing. Not so necessary with the KX3 and auto tuner, but with an 817 or KX3 without tuner, a must. Have fun. Scott ka9p In a message dated 4/3/2016 5:38:09 A.M. Central Daylight Time, [email protected] writes:
Thanks for all the responses. Don, your comments are much appreciated and I planned on building a bracket just as you describe and mounting my whip/counterpoise to the top of a trekking pole.. Again, I'm not asking about antenna performance. I will add the counterpoise in actual operation. I'm asking if anyone out there who actually owns the MFJ-1820T can please connect it directly to a antenna analyzer and check 20M performance. Yes, I believe these antennas actually DO resonate just as they are. I believe mine is 17M (mislabeled), not 20M, and just looking to confirm that. Thanks & 73, Barry N1EU On Sun, Apr 3, 2016 at 9:34 AM, Bruce Nourish <[email protected]_ (mailto:[email protected]) > wrote: Did you have a counterpoise when you swept the antenna? If not, you're only looking at half your antenna, especially as the RigExpert is almost all plastic. On Sun, Apr 3, 2016, 01:15 Barry N1EU <[email protected]_ (mailto:[email protected]) > wrote: If anyone else out there has an MFJ-1820T and also an antenna analyzer, I wonder if you could please do me a favor. Please just connect the whip directly to the analyzer and tell me what the SWR looks like across the 20M and the 17M bands. I swept my MFJ-1820T with my Rig Expert AA-30 and my MFJ-1820T is resonant on 17M, not 20M. I'm wondering if I have a mislabeled MFJ-1817T. Thanks & 73, Barry N1EU __._,_.___ ____________________________________ Posted by: Barry N1EU <[email protected]> ____________________________________ _Visit Your Group_ (https://groups.yahoo.com/neo/groups/KX3/info;_ylc=X3oDMTJmMzRpanF0BF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARzZ WMDdnRsBHNsawN2Z2hwBHN0aW1lAzE0NTk2Nzk4ODY-) * _New Members_ (https://groups.yahoo.com/neo/groups/KX3/members/all;_ylc=X3oDMTJnNDlucmNtBF9TAzk3MzU5NzE0BGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA 2MzEwOARzZWMDdnRsBHNsawN2bWJycwRzdGltZQMxNDU5Njc5ODg2) 12 (https://groups.yahoo.com/neo;_ylc=X3oDMTJlY2c3MWJuBF9TAzk3NDc2NTkwBGdycElkAzc0NTIwOTQ3BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTQ1OTY3 OTg4Nw--) • _Privacy_ (https://info.yahoo.com/privacy/us/yahoo/groups/details.html) • _Unsubscribe_ (mailto:[email protected]?subject=Unsubscribe) • _Terms of Use_ (https://info.yahoo.com/legal/us/yahoo/utos/terms/) __,_._,___ ______________________________________________________________ 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]
