I bought a used AOR SA7000 to evaluate and although its not a great performer, it does work across the advertised range. For VLF through HF it uses a 6ft long whip feeding a high ratio transformer to match the very high impedance of the whip to roughly 50 ohms. VHF/UHF is handled through a shorter whip with various coils to resonate at different parts of the band. Both whips are then fed to an internal diplexer to feed a single output connector.
VLF/HF performance is noticeably better than using a Radio Shack Discone but nowhere near something like an end fed PAR SW wire antenna will pick up. Comparing the SA7000 to my 133ft long 80m offset center fed dipole on HF, I can hear lots of stuff on the dipole that doesn't even exist on the AOR antenna.
VHF/UHF on the AOR might be a little better than a Discone at a few discrete frequencies but I think a Discone is better overall for most of the VHF/UHF band. I did not test the AOR at or above 800MHz, so I don't know how it works there and a Discone is known to be a little deaf in the 800 range.
I think the cost of the SA7000 is very high but if you only have space for a tiny antenna and you want to receive everything, its better than no antenna.
As a side note, several companies that sell Emergency Alert System (EAS) equipment for commercial broadcast also sell or recommend the AOR SA7000 antenna for their equipment because the EAS signals are usually picked from AM broadcast, FM broadcast subcarrier or NOAA weather channels at 162MHz. The AOR antenna sort of picks up all these frequencies with one antenna and I bought my evaluation antenna to see if reception of EAS frequencies could be improved, which it can and by a lot!
prcguy