[Chas]

My theory, without consulting my files full or antenna documentation I have. Is that the Philco antenna as well as antennas marketed by other radio manufactures during the "heyday" of shortwave. Are, aperiodic, such an "antenna" will have a high feedpoint impedance and wont match any feedline. So such feedpoint devices suit that purpose. What cannot be discounted that the "action" of the match system may include using the feedline as part of the reception as a vertical component. At certain times of the day and at lower wavelengths the short range of ground signal is very dominant. IMHO the antenna will be a compromise, that is not bad as a resonant antenna performs poorly off resonance.

Interestingly, RCA had an antenna FWIR called a "Spider-Web" I may be wrong in the terms but it looks a lot like the lower half of a spider web. What I believe it does with wire and a Delta match is to achieve a certain "broadbandedness" as well.

Such broadband, well, multi-band antennas are being built today, wire construction, awkward to hang and not at all stealth but they are resonant and matched to coax feedline for use with a transmitter. I salvaged at least two of these and did have one hung long ago. The other from an estate in 2007 I have rolled up in storage. I think it is a commercial unit or one that someone has put considerable labor into. Both these antenna are copper-weld wire, very strong because of the weight of the entire antenna system.

A word Simon:

Avoid manipulating the mica condensers by twisting, the clip the attaches the wire to the stack of metal plates can partially open and disconnect, making the cap go lower in capacity.

Good Work!

Chas