To start evaluating this type of Magnetic Loop Antenna (MLA), we must first say that this is a „compromise antenna“. The fact is that we can get something by sacrificing something else.
The small size and an easy transportability, a nice mechanical design, simple assembly, easy mounting, this all would attract mainly mobile users. Making MLA-ER ready to operate is really easy and no skills are needed. Basic tuning (band switching) is quite easy by swapping capacitive segments. So far all sounds fine, but then...
To make any magnetic loop antenna operate at the peak of its theoretical performance (and not to have a nice technical artefact only), a MLA must (contrary to a piece of a wire that can operate always and anywhere) meet some additional physical conditions. Some are determined by a good technical design and technology used by the manufacturer, other conditions should be met by the user at the final location. The resonant-loop systém must be optimized (tuned), otherwise the promised and promoted features of the MLA-ER would never materialize.
From my own experience I must say that using only a SWR meter to tune MLA-ER is bothersome, inaccurate and simply poor. A beginner would be certainly lost. I can confirm everyting what the author had written. The best for tuning is using an antenna analyzer, AA. Then the tuning can také less than a minute or a couple of minutes. A „professional“ may succeed even without an AA, but those are rare birds. They might know and require no instructions.
To conclude my evaluation of MLA-ER: This antenna is mainly suited for digital operations where it is not needed to tune over a larger frequency sector in a band. Certainly I would not recommend this antenna to beginners without an experience in antenna techniques. They can really be quite dismayed by a poor MLA tuning which is required to use all magnetic loop antennas.
Any tiny change in the vicinity like turning the loop by several degrees, or hanging wet laundry on a drying hanger close to the loop, can mistune the antenna. With an AA the problems are gone. The evaluated MLA-ER is a good and low-cost solution for many radio amateurs who cannot build their dream antenna. The MLA-ER can be also used in a situation which is not optimal, but this would be another story of thinking and using it.
73, Emil, OK5AG