Many LowFERs are also licensed radio amateurs, although an amateur radio license is not required for LowFER communications in those countries in Region 2, as long as the power is below a nationally prescribed limit, often 1 W.[4][5] Practical antennas at these frequencies are much shorter than the wavelength, making it difficult to efficiently radiate much useful power.
By current U.S. and Canadian regulations, LowFER transmitters may not have antenna and feed line lengths longer than 15 metres (49 ft), or final RF stage input powers that exceeds 1 watt.
Even with such short antennas and low transmit power, LowFER stations have been heard at distances approaching 1,000 miles by listeners using sophisticated receiving setups.
[4] In Europe, and generally in ITU Region 1, the LowFER frequency range (160–190 kHz) is used for broadcasting and is unavailable for two-way communications use.
[4] HiFER is high-frequency experimental radio operating within a 14 kHz-wide band centered at 13.56 MHz.