Most, if not all, of the design information presented on that FB group is simply wrong. The gimmicky transformer that is advocated works well only with truly resonant half wave wires and only on the bands on which the system is resonant. And even then it is not nearly as good as a simple LC tuner. The reason that group keeps going and propagating their rubbish is they systematically exclude and block anyone who produces actual data that refutes their ridiculous claims. Read the EFHW trail here and you will be much better informed than if you rely on those videos and the group chat.
WA8TOD
