LowFER
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LowFER (Low-Frequency Experimental Radio) is a license-free form of two-way radio communications practised on frequencies below 500 kHz.
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[edit] Practices
LowFER operation is practised in the United States and Canada on radio frequencies between 160 kHz and 190 kHz. In the US, license-free operation is also allowed on the medium frequency band, also known as the AM Broadcast Band. Proposals have also been made for Amateur radio operations at 136 kHz with a number of U.S. Ham's holding experimental licenses authorized to conduct tests on that frequency. In Europe, the LowFER band is used for broadcasting and is unavailable for two-way communications use. There have been some changes in the LowFER frequency authorizations that allow operation on 73 Kilohertz in England by Amateur Radio operators.
Radio operators who conduct low-frequency experimental operations on the LowFER band are known as LowFERs. Many LowFERs are also licensed radio amateurs, although an amateur radio license is not required for LowFER communications.[1]
[edit] Equipment
Antenna efficiencies at these frequencies make it difficult to radiate much useful power. By current US and Canadian regulations, LowFER transmitters may not use antennas longer than fifty feet or final RF stage input powers that exceeds one Watt. Telegraphy and digital modes are the most commonly used for communications, but speech transmission via Amplitude modulation (AM) or Single-sideband modulation (SSB) is also allowed. Even with such short antennas and low transmit power, lowfer stations have been copied at distances approaching 1,000 miles by listeners using sophisticated receiving setups [2]
[edit] MedFER
Similar to LowFER, MedFER is medium-frequency experimental radio. MedFER enthusiasts operate using 0.10 W (a tenth of a watt) and a three-meter long antenna between 510 and 1705 kHz.[3]