The SWT is intended for biochemical and biomedical professional labs. Here, the test tube is used for good reason. Therefore, a means of transport is needed to transfer the biological information from one test tube to another over some distance. Out of the units, consisting of a flat coil and an extendible/detachable ball electrode, one serves as a transmitter with an integrated function generator and the other two are receivers for the carrier wave. In addition to that both receivers have a modulation option for e.g. Rife frequencies, which are pre-stored on the Tablet PC. 
 
The extendible antennas of the SWT have technical reasons. Minimal differences between the two receivers cause to different voltages and the LEDs illuminate different. Fine tuning is possible by a slightly longer or shorter antenna adapting the wavelength.
Overall, the range increases while the antenna length is increased.
 
Some more information:
https://www.meyl.eu/go/30_Books/Docu2_Eng_1.4_preface-ISBN_978-3-940-703-25-5.pdf