Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

## Re: LF: Loop Conundrum

 To: [email protected] Re: LF: Loop Conundrum Marco IK1ODO -2 <[email protected]> Mon, 21 Jul 2008 14:07:53 +0200 <[email protected] m> <[email protected]> [email protected] [email protected]
 ```At 13.29 21/07/2008, you wrote: ``````Was pondering this while out walking the other day, and couldn't come to a satisfactory conclusion either way... A small magnetic loop mounted vertically has a defined radiation resistance that is a function of its diameter, a loss that is function of its conductor and hence a loss or efficiency that is the ratio of the two. It is resonated with a good quality vacuum capacitor, and fed/matched by any suitable metrhod. Lets also leave aside all the myth and folklore about small loops, and also ignore the environment for now. It also as a radiation pattern with nulls. Now, I take two identical such loops and mount then on the same centre line but at right angles to eachother so there should be no coupling between them, whatsoever. Now, I connect the two loops in series and resonate the combination with a single capacitor of half the original value. The resulting radiation pattern should have the nulls filled in, and be a reasonable approximation to omnidirectional in azimuth. BUT... What is the resulting change in efficiency? ``````Andy, just my 2 cents: you have two magnetic fields in phase, that sum as vectors. ```So, from a distance you see only one vector, sum of the two, with nulls and so on; and you sum the areas of the two loops, projected on the plane orthogonal to the vector. If the loops are orthogonal between them you have a 1.41 times the effective area, and two times the resistance. The radiation pattern is not omnidirectional at all, and the total efficiency decreases. ```This is an intuitive reasoning... not scientific, HI. 73 - Marco IK1ODO / AI4YF ```
 Current Thread LF: Loop Conundrum, Andy Talbot Re: LF: Loop Conundrum, hajo . brandt . dj1zb Re: LF: Loop Conundrum, John Andrews RE: LF: Loop Conundrum, Chris Trayner Re: LF: Loop Conundrum, Alan Melia Re: LF: Loop Conundrum, g4gvw LF: RE: Loop Conundrum, Chris Trayner LF: RE: Loop Conundrum, Gary - G4WGT Re: LF: RE: Loop Conundrum, Mitch Buchman Re: LF: RE: Loop Conundrum, Warren Ziegler Message not available Re: LF: Loop Conundrum, Marco IK1ODO -2 <= Re: LF: Loop Conundrum, Rik Strobbe LF: RE: Loop Conundrum, Lee Hudson LF: Loop conundrum, Andy Talbot