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## Re: [TowerTalk] Elevated vertical

 To: Towertalk Re: [TowerTalk] Elevated vertical Ken Sat, 24 Dec 2011 11:15:43 -0500 mailto:towertalk@contesting.com>
 ```Paul, I think you forgot to differentiate between the actual SWR and what a meter may read ;-) Just because a meter says the SWR is 5:1, doesn't necessarily mean it is so. A meter at different points may indicate a different SWR, but that may not be the actual circumstance. Besides, where did you get an SWR meter for a 600 ohm balanced line? ;-) Inquiring minds want to know! LOL My Christmas wish for all: May Santa bring you an 80 m open wire fed dipole on a pair of 60' towers with plenty of open wire line, and a quality balanced auto-tuner and then we can end these discussions! LOL. (j/k) Yeah, I know, for the real hams, it has to be a rotatable dipole on a 90' tower. 73 es Merry Christmas to all, Ken WA8JXM On Dec 24, 2011, at 10:38 AM, Paul Christensen wrote: > > Sometimes VSWR does change significantly along a line -- and not always for > reasons of loss nor common-mode RF current on the outside of a coaxial line. > Consider this example: > > At the operating frequency, a dipole at its input terminals is exactly 50 > ohms resistive (50+j0). Let's feed the dipole with an electrical half-wave > of low-loss 600-ohm open line. VSWR on the line is 12:1. Correct? > Finally, let's connect a random length of 50 ohm, low-loss coax to the input > of the 600 ohm line. > > What is the VSWR on the 50 ohm section of line? > > Possible Answers: > > A. Is it still about 12:1 because VSWR does not change on a low-loss line. > B. Not enough information because you didn't state the coax length. > C It's now about 6:1 > D. It is now 1:1 > E. You can't terminate a coaxial line into a 600-ohm balanced line without a > current balun and get an answer. > F. None of the above. > > Bonus question: What is the impedance at the input to the 600-ohm line > section? > > So, here we have one transmission line composed of two types. Ignoring > loss, is the VSWR really the same at all points on the transmission line? > > Paul, W9AC > > _______________________________________________ > > > > _______________________________________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread Re: [TowerTalk] Elevated vertical, (continued) Re: [TowerTalk] Elevated vertical, TexasRF Re: [TowerTalk] Elevated vertical, Ken Re: [TowerTalk] Elevated vertical, Paul Christensen Re: [TowerTalk] Elevated vertical, Paul Christensen Re: [TowerTalk] Elevated vertical, Al Kozakiewicz Re: [TowerTalk] Elevated vertical, K8RI Re: [TowerTalk] Elevated vertical, Al Kozakiewicz Re: [TowerTalk] Elevated vertical, Hank Garretson Re: [TowerTalk] Elevated vertical, Paul Christensen Re: [TowerTalk] Elevated vertical, Ken <= Re: [TowerTalk] Elevated vertical, Paul Christensen Re: [TowerTalk] Elevated vertical, Al Kozakiewicz Re: [TowerTalk] Elevated vertical, Jim Lux Re: [TowerTalk] Elevated vertical, john Re: [TowerTalk] Elevated vertical, TexasRF Re: [TowerTalk] Elevated vertical, Mike Ryan Re: [TowerTalk] Elevated vertical, Tom Osborne Re: [TowerTalk] Elevated vertical, john Re: [TowerTalk] Elevated vertical, Jim Brown