Towertalk
[Top] [All Lists]

## [TowerTalk] Voltage vs Current feed

 To: [TowerTalk] Voltage vs Current feed W8JI@contesting.com (Tom Rauch) Mon, 15 Oct 2001 20:17:41 -0400
 ```> Am I correct? Because of the open circuit (usually) at the far end of > the antenna, the current must be zero throughout a cycle. If this is > true, it seems to make sense to begin analysis starting at the far end > and work back to the source using the thoughts expressed in the above > posting. The feed then can be seen to be a function of antenna > length. Do standing waves alter this observation? That's all right as far as I could see except current never really is absolutely zero at the ends because there is still coupling off the end into the electric energy storage field. You start at the open end, or farthest point, and work inwards. The voltage maxima (or loop or node) is at the open end, because there is "nothing much" for current to flow into. The current loop, node, or maxima is generally 1/4 wl in, but that assumes the wire is not loaded in any way, including having most or all of the electric field surrounding the conductor in a dielectric with a Vp of light speed. Radiation comes from charge acceleration, and so the amount of EM radiation from any point relates to the ampere/feet of the system. That's why books tell us to keep the current loop (or node or maxima) as straight as possible, and why antennas like the CFA and EH antenna are only someone's wild dream. The large close effects are induction fields related only to energy storage (magnetic from the movement of charges and electric because of the distribution of charges), but these fields decay much faster than the weaker radiation field which is what we use to communicate. Loop antennas and loaded antennas are the ones hardest or impossible to generalize. That's about all we need to know in the world except lefty loosey righty tighty and poo don't run up hill. 73, Tom W8JI W8JI@contesting.com List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems, Trylon Titan towers, coax, hardline and more. Also check out our self supporting towers up to 100 feet for under \$1500!! http://www.anwireless.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
 Current Thread [TowerTalk] Voltage vs Current feed, Pete Smith [TowerTalk] Voltage vs Current feed, Tom Rauch [TowerTalk] Voltage vs Current feed, RCARIELLO [TowerTalk] Voltage vs Current feed, Al Williams [TowerTalk] Voltage vs Current feed, Tom Rauch <= Fw: [TowerTalk] Voltage vs Current feed, n4kg@juno.com Fw: [TowerTalk] Voltage vs Current feed, Tom Rauch Fw: [TowerTalk] Voltage vs Current feed, Chris BONDE Fw: [TowerTalk] Voltage vs Current feed, n4kg@juno.com Fw: [TowerTalk] Voltage vs Current feed, Pete Smith