I tried to google this but got lost in the mire! Anybody; The math to determine how much I should lengthen/shorten a dipole to move the resonant frequency from where it is to where I want? Must have
(468/Original Frequency) - (468/New Frequency) = Length to shorten in Feet I tried to google this but got lost in the mire! Anybody; The math to determine how much I should lengthen/shorten a dipole
It's all good now, dipole is 1.1:1 at the end of the coax right about 7.060. Worked VU7RG on 022 and an RU4 about 012 just to be sure it works. The dipole slopes of the tower to the (sort of) north (
ORIGINAL MESSAGE: -- REPLY FOLLOWS -- While the above method will probably work well enough, there is a slightly more accurate method, since it does not depend on the accuracy of the 468 factor to be
The best way to solve the problem once and for all is to feed the dipole with open wire tuned feeders, using a balanced, link-coupled antenna tuner. That way you can instantly change the resonant fre
One caveat, which seems obvious once you know it, is that this works only for changes of a few percent. Don't go trimming your 80 meter dipole for 40 meters by doing this... Jim, W6RMK ______________
Or, putting a tuner at the feedpoint, and then using coax, so you don't have to fool with openwire line and worrying about the length of the feedline. The loss in the tuner will be pretty much the sa
Uhhhh....I guess I don't understand the last phrase. What's simple about getting up from the rig, walking to the coat closet, getting my coat and hat and boots and mittens, going outside to my tuner
That's true to a point. I have used efficient homebrew antenna tuners my entire ham radio life and wouldn't be without one. But you can get some REALLY ugly radiation patterns from trying to use the
Author: "Trent and Lorraine" <vk4ti@sampson.net.au>
Date: Sat, 20 Jan 2007 10:53:57 +1000
I would suppose the efficiency (?) and having a low SWR on all bands are again confused. I still go by the theory that multibanders in general (G5RV and variations thereof) radiate equally poorly in
Sorry, but I wasn't confusing the two points at all. When I said "efficient" I was referring to losses in the tuner. You can have a high SWR on the line and still have low losses there, but if you ha
remote or automatic control would, of course, be indicated <grin> Aw heck, if they weren't going to hang around waiting for you, they weren't worth waiting for, right? And besides, if you followed th
Point is, you don't have to do that with an SG-230. -- 73, Cecil, w5dxp.com _________________________________________________________________ Search for grocery stores. Find gratitude. Turn a simple
A standard G5RV is a pretty good antenna for 80m, 40m, 20m, and 12m. -- 73, Cecil, w5dxp.com _________________________________________________________________ Laugh, share and connect with Windows L
Martin, Last year I needed to tune a 40m dipole to resonance so I created an Excel spreadsheet to help me determine the adjustments. I have attached a copy for you to review. This attachment won't ma
One can get a lot of advice and/or opinions on any topic. Be very careful to separate technically sound judgement and advice from other stuff. Bruce _______________________________________________ __
I prefer the 'close enough' adjustment method. This works for any units and any band. The formula is just length*change/frequency As long as the units of 'change' (how much you want to move the reson