Tell you what I would do, Marty......Get you some T-200-43 torroids and wind your coax thru these a few times at about 35 feet below the feed point. Then I would also do the same, or make a 10" dia coil of 8 or so turns of coax on a form right where the coax enters into the shack. Further details on this have a read of Jim Browns article -- ' http://www.w4ava.org/articles/k9yc-rfi.pdf
This antenna will certainly generate common mode currents on the feed line. And whether they use that to accentuate the performance or not, these currents will cause you problems in the shack. Certainly try to get the antenna up to 35 feet or so. By doing so also gets you above the buildings and noise, etc. And most important, it will see the horizon in a single story house neighborhood. I had a 40 meter ground plane vertical up at about 40 feet years back and it worked gangbusters. There is alot of information on the web about this antenna..... or really about the Comet, Diamond or Eagle versions of this design. MFJ licenses the design and manufacturing from Comet. Google "N6PET Comet Antenna CHA-250". He describes what is inside the matching xfmr and his take on performance. Even Monitoring Times got into the picture with a comparison review with the GAP Titan. Gooogle that too. On the higher bands it might do OK, especially if you get it higher in the air. But not on the lower bands 40 and below.... just because it is quite a compromise -- on 80 it is about 35 electrical degrees long. About 1/3 a full size 1/4 wl vertical . On receive it probably does OK. Heck 3 foot long active antenna out performs long wires on receive. Transmit is a different story. Maybe a 40 and 80 dipole will get you better results and again depends on how high above ground it is.. I wouldn't stop using it. Just improve the performance by getting it higher in the air and choking the coax appropriately, to eliminate RF in the shack. And run 250 watts into it if you can. It'll take it and that will improve your radiation strength. GL and 73...Rick -- W5R <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Fri, Mar 27, 2020 at 3:42 PM Neal Naumann via BVARC <[email protected]> wrote: > Hmmm... MFJ doesn't shed much light on what is in the "matching section". > Hopefully, it's not a 50 ohm resistor! Maybe it is a 9:1 balun and this is > like an end-fed wire. But then there is this from the manual "Raise the > antenna and mast assembly up and mount in the final position. For best > operation it is recommended that the antenna be put up about 35 > feet in the air although reasonable results are obtained with a > lower height". So they are hoping to use the mast as part of the > radiator...The other problem is that you would like to operate on 80 meters > and only have 28 feet of antenna. So, I'm not sure where I'm going here > with your problem. Maybe something in breaking down and arcing in that > "matching section". If it's a 9:1 balun...that might be why it's only > rated at 150 Watts CW? > > Neal N5EN > > On Fri, Mar 27, 2020 at 11:21 AM Martin Blaise <[email protected]> > wrote: > >> I have a mfj 2386 vertical at my house . It receives okay but transmit is >> questionable at best. I contacted mfj and asked how to add radials and >> they >> said that antenna is designed for without verticals and did I have the >> bottom of the antenna at 37 feet up? I only have it about less than half >> of >> that. I need a taller support. Anyway it’s broadbanded and my 450d >> internal >> antenna tuner shows good swr match but last night on 80 meters I tuned up >> and the antenna matched fine but when I transmitted on cw with flidigi it >> showed swr mismatch. Rf in the shack? Trouble shooting ideas? Thanks >> ______________________________________________________________ >> NARS mailing list >> Home: http://mailman.qth.net/mailman/listinfo/nars >> 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 > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > -- Rick Hiller *e-mail: [email protected] <[email protected]>* *Cell: 832-474-3713* *Physical: 9031 Troulon Drive* * Houston, TX 77036* <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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