For a long time, I was looking for a usable shortwave antenna, since my random long wire antenna was not very useful, especially on the tropical bands. Additionally, it received all kinds of noise.
A DX colleague offered me his self-made magnetic loop antenna with integrated amplifier, and so his antenna is now in use in my shack.
It works very well, and I made quite number of nice receptions in the
tropical bands, although in the same room, two computers were working
at the same time. With my former random long wire, this was impossible.
From the technical values, this antenna is compareable with the Grahn
GS-2, and in the lower frequency ranges, it is even more selective.
This antenna matches not only the loop module, but also a shorter random wire.
On the back side, you can regulare the amplification. Two connectors, one for PL-239 and one for BNC are also there.
This loop antenna is optimized for very low power consumption. It runs with two AA accumulators (or two norml AA cells), whose power can be read on a special voltmeter: It does not start from zero, but shows only the interesting power range of 1.8 to 2.8 Volts. Below that, you can be sure, that the accumulators are empty, and so, lower values are not interesting.
On the loop module, you can select the optimal frequency range, like on the professional Grahn loop antennas. The reception range is very broad and ranges from 2.1 to 36MHz.
Note: I often get enquiries for the schematics or construction plans of the loop. Unfortunately, I cannot answer them positively, since there don't exist any documents to this hand-made loop, but there are plenty of general documents for building MagLoops online, and for those, who want a professional antenne, a Grahn Loop antenna is certainly the best solution.