These are all variations on a lossy transformer. Alpha and Chameleon don’t actually tell us that, but the broadband SWR charts tell the story. An efficient antenna has sharp SWR dips at resonance. Resistive losses make those very broad.
The classic design of this sort is the Comet CHA-250B. Comet is totally up front about the losses in their description of the transformer.
CHA-250B Transformer Section
This is a the “magic” behind the CHA-250B, the transformer matching section.
The transformer on the original CHA-250 had smooth sides. The current version has a heat sink to dissipate heat created inside the transformer.
Yes, some of the RF that enters the power feeding section is turned into heat rather than transmitted as RF, but that is one of the compromises needed to create a broad-band, low SWR, multi-band HF antenna with minimal visual impact.
I don’t trust either Alpha or Chameleon because they don’t explain that tradeoff.
There are a few efficient broad-band antenna designs, but they aren’t convenient for portable use. Either they have fat, low-Q elements (cage dipole, bowtie dipole, discone) or multiple elements (fan dipole, log-periodic dipole array).
wunder