Sorry, that should have been addressed to Kirk! Not Rick. See, my brain is AWOL!
No trees were harmed in the production of this message, however, a great many electrons were terribly inconvenienced. ________________________________ From: BVARC <[email protected]> on behalf of Martin Blaise via BVARC <[email protected]> Sent: Thursday, January 16, 2020 4:34 PM To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]> Cc: Martin Blaise <[email protected]> Subject: Re: [BVARC] Antenna Theory Technical Question Do not use this kind of fan dipole see attached. On Thu, Jan 16, 2020 at 1:21 PM Kirk Kendrick via BVARC <[email protected]<mailto:[email protected]>> wrote: Rick, Fan dipole with all the wires the same length....and closely spaced. Resistance should be 2) unchanged as others pointed out. Coupling will cause broader BW like a cage dipole. Unless your antenna conductors are manufactured to limit variance.... Impedence in real world will be hard to model in a bundle that has varying capacitance due to uneven spacing and varying inductance due to twists and turns within bundle I'll throw out a slightly different thought. I think it would also model as a sleeve antenna. That would make the EZNEC model have only 1 dipole driven and all the other wires evenly spaced around it potentially with small gap at feed point (that shouldn't be needed since it's a zero voltage point). At least, my mental model has them as (close to) equal. But my brain wanders a bunch. 73, Kirk KK2Z PS: My favorite "work of art" sleeve dipole in one of the early antenna compendiums was a vertical made up of a ring of resonators -- one for each band -- around a driven vertical in center. From: Rick Hiller <[email protected]<mailto:[email protected]>> To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]<mailto:[email protected]>> Subject: [BVARC] Antenna Theory Technical Question Message-ID: <CABNEQE_mKnBH3if0mmvenpjopxJJf+c-ap=+eosvapc+vtd...@mail.gmail.com<mailto:eosvapc%[email protected]>> Content-Type: text/plain; charset="utf-8" I am in the midst of analyzing a Ham market HF antenna. Still building the EZNEC model, but working it thru the gray matter. Case: Take a 1/2 wl dipole antenna -- center fed. Each side is made up of multiple, equal length wires that are each insulated, parallel, and closely spaced. The wires are connected/common at the center feed point, but open at the far end. If, at this length, each wire's material DC resistance is 5 ohms....does using multiple wires in parallel, as described above, 1) lower the total RF material resistance, as resistors in parallel....or 2) does it stay the same or 3) does it become additive? Any comments would be appreciated. I've got my hypothesis, but wishing additional input. Thanks and 73 ...Rick W5RH ________________________________________________ Brazos Valley Amateur Radio Club Get on the air - 146.94 Repeater Volunteer now for the Houston Hamfest BVARC mailing list [email protected]<mailto:[email protected]> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
________________________________________________ Brazos Valley Amateur Radio Club Get on the air - 146.94 Repeater Volunteer now for the Houston Hamfest BVARC mailing list [email protected] http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
