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## Re: [TowerTalk] Phasing verticals and stubs

 To: "Tom Osborne" ,"Towertalk" Re: [TowerTalk] Phasing verticals and stubs Jim Lux Thu, 06 Apr 2006 06:33:24 -0700
 ```At 05:42 PM 4/5/2006, Tom Osborne wrote: >Yes, I meant they are in an equilateral triangle. Had a brain fart. > Lots of postings on this subject, but nobody has yet answered my original >question. I'll post it again. > >I have 2 stubs, separtated by a 1/4 wave phasing line on my single vertical. >Will these stubs affect the phasing of the verticals. That was what I was >originally asking. Thanks and 73 Coax stubs? Like the ones used as a trap for other bands? Or, are they part of the tuning network? Either way, they'll have some inductance or capacitance, and so, will change the phase. The real question is how much. How long are the stubs, are they open or shorted? If you have Excel, download the XLZIZL spreadsheet from AC6LA http://www.ac6la.com/xlzizl.html You can enter in all the details of your transmission lines and stubs, and run the numbers in a few minutes. XLZIZL won't do the full network calculations with the mutual impedances, but at least you can see if the "feed system" is reasonably flat over the frequencies of interest. If you have multiple antennas and you want to understand the effects on the system, there's 4 basic ways to go about it: 1) Build a NEC model, and use NT cards for your transmission lines and stubs, putting in the appropriate numbers for your lossy transmission line. 2) Determine the mutual impedance matrix for the antennas (by measurement, or by estimating with equations/tables). Build a model in one of the many versions of SPICE out there (helps if you use one that does real transmission lines). 3) Do the matrix calculations by hand (Yikes... but doable.. if you have Matlab or Octave or Maple, this gets easier.. ) 4) Measure it on your system. It's pretty easy to make and calibrate current probes, and an inexpensive dual trace oscilloscope will let you directly measure relative phases and currents. Jim, W6RMK _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread Re: [TowerTalk] Phasing verticals and stubs, (continued) Re: [TowerTalk] Phasing verticals and stubs, Bill Re: [TowerTalk] Phasing verticals and stubs, Jim Lux Re: [TowerTalk] Phasing verticals and stubs, Ian White GM3SEK Re: [TowerTalk] Phasing verticals and stubs, Clive Whelan Re: [TowerTalk] Phasing verticals and stubs, Jim Lux Re: [TowerTalk] Phasing verticals and stubs, Tom Osborne Re: [TowerTalk] Phasing verticals and stubs, Gary Schafer Re: [TowerTalk] Phasing verticals and stubs, Tom Osborne Re: [TowerTalk] Phasing verticals and stubs, Gary Schafer Re: [TowerTalk] Phasing verticals and stubs, Tom Osborne Re: [TowerTalk] Phasing verticals and stubs, Jim Lux <=