At first glance the loop antenna without a capacitor, looks like a small quad which is sometimes termed as two dipoles connected with each other. Thus with a symmetrical current flow it will act the same as a normal dipole. As with all antennas when it is used at other than the design frequency the current flow becomes unsymetrical. (minimum current does not coincide with the physical end of the antenna) And like the G5RV, the current flow, in an effort to becomes symmetrical in form, is willing to move down the transmission line. You could say that it also could revolve around the circle until it reached a cycle of symmetrical proportions (remember we must be open minded if we are to probe for new ideas)

When a capacitor is added to the loop it becomes resonant at a different frequency. The existence of the capacitor modifies the current flow, so that it can become symmetrical or resonant. (A repetitive current flow path) Thus a variable capacitor can be used as a controlling factor instead of the transmission line! With the loop antenna, multi band operation is viable with out the contribution of a transmission line or a stub. Those who are proficient in the art of antennas accept it as a solid performer.

The variable capacitor provides an exciting method of having a single antenna or radiator that could be tuned to a particular frequency.

In real life however it would be difficult to convince anybody to use the term mono bander in the same breath as small loop antenna, and rightly so! It does not have an efficiency that could compare with a dipole or as directive. It does radiate because the electrons follow a curved path fig 1.

When viewing the loop in mechanical or water flow terms, it becomes obvious that friction (cavitation) could be reduced if an outlet was supplied. Two relief paths would be better so with that thought in mind it is natural to add two elements to the periphiary of the loop. increase the efficiency of water flow, an outlet. Fig 5.

It can then be seen that we have moved back towards a G5RV in a loose sort of way. That at design frequencies we have symmetric current flow.Fig 6 This time instead of cutting the stub length to suit for non design frequencies, the same result can be obtained with a capacitor and gain the versatility of being TUNABLE.

At this point some would say we have found the answer to our need, others would immediately retort snake oil! A well worn, safe phrase used by those who have been previously defeated in 'the quest'. Even though we have only used well accepted known antennas, albeit we have looked at them in a somewhat unorthodox fashion, we must delve further for MORE supporting, presently accepted, facts.

To have improved multi band performance, we must find a way to resist the formation of multi lobe radiation. In viewing the sample G5RV radiation patterns fig 7, it is important to review situations where the bi-lobe or directional pattern is maintained when the dipole length is longer than 1/2 wave.

However the two side lobes are in addition to the main lobe pattern created by the dipoles in echelon and are generated under the influence of the remaining parts of the antenna. When the center area and stub are replaced by a loop then these side labels do not appear with the suggestion that the radiation from the first loop reinforces the main two lobes.