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## Re: [TowerTalk] Problems on a 2el vertical Array

 To: Re: [TowerTalk] Problems on a 2el vertical Array "Mark Beckwith" Fri, 9 Jan 2004 12:11:47 -0600
 ```> Hi guys, > > over Christmas I set up a 2el vertical Array for 40m. [snip] >The pattern shows, that I should have at least 10dB >on EACH station and 15-25dB f/b on DX stations. >I heard only a few DX stations where I really had >25dB f/b... but this was the big minority (maybe 5 >out of 100). Often I didn't notice any f/b at all. >(especially on stations closer than 2500km). [snip] >It would be great to get some feedback from >the more experienced Array-builders! Hi Toby. You didn't say how far down the stations off the back were actually measuring - all you said was it wasn't the 25db you were hoping for. When I build these arrays (I've made a few) if I just build them and split the power with a TEE and have the different lengths of coax for the phasing, I might get an S-unit to 10db difference when I switch. That's usually sufficient for me. (I'm from the "hey, you can tell a difference!" school). Where you may not be realizing your model is: The model probably allocates power equally (50/50) between each vertical, right? In real life when you feed it, the SWRs on the two verticals are different because of the fact that there's a second energized vertical nearby having some kind of effect on it, and each is being fed in parallel with something else with a different length of coax, blah blah blah. Gets too complicated for me, anyway. This is the point at which my eyes usually glaze over. Better Men than I will go further: basically the induced SWR means the power doesn't get split 50/50 - it becomes 60/40 or 70/30 or whatever - not 50/50. Anyhow, if you plugged in some uneven amounts of energy at your sources in your computer model, you will see a degradation of the pattern - like you are experiencing in real life. Another factor which doesn't help is when DX signals arrive from non-straight-line directions or multiple directions. The real-life way to get the power to split 50/50 is to put a tuner at the base of each vertical and a tuner right before the TEE. Once you get all tuners to tune out all reflected power at all three points, then your power is being split in half, and you will experience more like the F/B in the model. The people reading who think tuners are blasphemous will probably propose other answers with a lot of strange symbols and words I don't understand. Anyway, while they're going through all those histrionics, I'll be on the air working guys. :) Congratulations Toby for getting your MFJ to actually make your parts imitate your computer model. You must be one of those Better Men. I'll take a parasitic array any time, mostly because phased ones drive me to drink. Hic. Mark, N5OT _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] Problems on a 2el vertical Array, Tobias Wellnitz Re: [TowerTalk] Problems on a 2el vertical Array, Jim Lux Re: [TowerTalk] Problems on a 2el vertical Array, Tobias Wellnitz Re: [TowerTalk] Problems on a 2el vertical Array, Mark Beckwith Re: [TowerTalk] Problems on a 2el vertical Array, Mark Beckwith <= Re: [TowerTalk] Problems on a 2el vertical Array, Rick Karlquist Re: [TowerTalk] Problems on a 2el vertical Array, Mark Beckwith [TowerTalk] Re: Problems on a 2el vertical Array, Jan Erik Holm Re: [TowerTalk] Problems on a 2el vertical Array, Jim Lux Re: [TowerTalk] Problems on a 2el vertical Array, Mark Beckwith Re: [TowerTalk] Problems on a 2el vertical Array, Jim Lux [TowerTalk] An unusual tuner, Mark Beckwith