```Quoting Andy Talbot <[email protected]>: ``````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? Argument 1: Two identical loops = two times the loss R, but also two times the radiation resistance (since they don't couple) so net efficiency remains the same. Argument 2 : Chu-Harrington relates efficiency / Q / bandwidth / volume enclosed. Therefore, as the enclosed volume has increased, the effciency ought to rise. Both arguments developed little side trendrils & thoughts as I walked and pondered, and both appear valid in their own way. So the floor is open for discussion :- And where does the net radiation pattern fit into the equation? Does it, at all ? -- Andy G4JNT www.scrbg.org/g4jnt ``````Another 2 cent (or 2 penny): I just simulated the antenna as described by Andy with Mmana_gal: - The radiation pattern is (almost) omnidirectional. ```- The radiation resistance doubles compared to a single loop. But as you use the double amount of wire (= double losses) efficiency will be about the same I guess. ```73, Rik ON7YD - OR7T and compred it to a single loop Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ```