Antenna Help For(and Hopefully From) Readers

摘要

This month the column is going to cover a variety of topics rather than one project. We start off with reader feedback regarding the last column on using loop antennas for transmitting. Oleh, KD7WPJ, reminds us that the RF currents are very high in a loop antenna and that any resistance in the loop very quickly reduces its efficiency. Connections between segments can be particularly troublesome. When practical, the loop needs to be one piece of metal. Segments as used in the G4TPH antenna can be problematic. G4TPH used wide antenna segments with lots of contact area as you can see in photo A. Thus, make sure the sections are clean where the elements come together and the connections are tight. Also, with any loop antenna used for transmitting, you need to have good low-resistance connections between sections.