CURRENT AMRAD LOW FREQUENCY (LF) and MEDIUM FREQUENCY (MF) WORK
AMRAD is once again pursuing experimentation on LF and MF frequencies, along with members of the Low Country Contest Club (LCCC) in Charleston, SC. With the FCC issuing NPRM 2015-15250 (a result of WRC-12), which includes the potential of new amateur radio bands at 2200 Meters and 630 Meters, the United States will follow follow other countries in allowing amateur radio operations at 135.7-137.8 kHz and 472-479 kHz.
While there is little commercial equipment available to the amateur at this point, one point of focus for AMRAD will be to identify existing equipment and/or designs to use on these new bands.
Another point of focus will be to evaluate various transmission methods to use effectively for two-way communications withing these bands. Whether basic transmission systems such as CW, or more sophisticated methods that can dig signals out of the noise, actual on-air testing should provide a basis for other amateurs to use in the future.
There are MANY challenges to operating on these lower frequencies. One is the lack of connercial equipment, but the major challenge is the transmit antenna. With the wavelengths involved, traditional antennas such as dipoles or verticals are impractical for the average amateur. This is another area that AMRAD will focus our experimentation on. Many AMRADers have typical suburban lots, so identifying antennas that would work within that limitation are important for future LF and MF amateur operations.
The following pages links will be updated as we continue our work. To make it easier to locate specific items, the information is broken down into different subjects:
- General LF & MF information
- Passive receive antennas
- Active receive antennas
- Transmit antennas
- Commercial LF/MF rigs (receivers/transmitters/transceivers)
- Receive preamps
- LF/MF Receivers
- LF/MF Upconverters
- Beacon transmitters, transmit down converters, and exciters
- LF/MF transmitters
- LF/MF transmit amplifiers
- LF/MF test equipment & accessories
- VLF/LF/MF Soundcard receivers
- LF/MF operating modes
- “How Tos”, FAQs, Concepts
- Legal information
- LF/MF sources of information
- Links to other VLF/LF/MF sites
Previously, AMRAD performed LF experiments from approximately 1990 to 2001. Information on these experiments can be found on this page: Previous AMRAD LF Work.