Hi Craig I honestly think that the polarization matter is not applicable here. All the theory around that is based in the thinking you will radiate to a long distance and not to 4 or 5 meters. The shape and angle of the electromagnetic field is not crucial to so short distances.

I think that to make a coil with the large of the vertical antenna is not right from the design point of view, the equation to design a loading coil antenna is so complex that only people that works specifically on them could get a good result, but always talking about antennas that have to irradiate to long distances.

When you connect the output of the transmitter to a vertical antenna, the antenna shows a load to the transmitter, basically is the impedance. If you roll the antenna in a coil then the impedance will change definitively and to get the same load for a shorter antenna ( or no antenna) you must to calculate a coil that I’m sure will have a number of loops and diameter that nothing will have to be related to the large of the original vertical antenna that you want to replace. To think that the large must to be rolled around a cylinder of plastic is a simplification.

Did it work? Sure why not if you leave a loose cable inside will work also.

In my shermans I roll the antenna cable of the Futaba’s around the speaker box and works great, but doesn’t mean that I did something scientifically correct. I don’t need to look for links as I have my handbook for antenna designs and couplers but I know that’s not necessary for our models.

Of course if you are designing an antenna radio for TX/Rx for the RC Army airplanes then should to use all the math.

Hey! anyway I think that all this thread as well as others were very useful for me and others too.