Is this author correct about using a λ/2 of wire for a coil to get the proper delay on a λ/2 collinear antenna?
I agree with him that there has to be a 180 degree current delay between λ/2 collinear elements, but if winding the phasing wire into an inductor (Figure 1D in his article) of a certain minimum value, couldn't that produce 90 degrees of current delay anyway, necessitating only λ/4 of electrical length to get to the other 90 degrees of current delay?
I agree that λ/2 of wire is needed if the design uses a hairpin stub, but if you're going to make a coil, I would have thought that would have produced some calculatable current delay anyway.
Secondly, does anyone else think that the separation he proposes as best (~16" on the 2M band) between λ/2 radiators, is actually not correct? Intuitively I would have thought that keeping them as close together as possible would actually be preferred to achieve a flatter main lobe and less prominent ancillary lobes?
Thirdly, I would think that if the coil he makes doesn't have sufficiently high impedance, it will be as if both elements are too long, or worse, that they are acting as one element.