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Program to receive weather reports and navigational warnings transmitted on longwave and shortwave bands in RTTY and NAVTEX modes. None additional hardware is required - your need only receiver and computer with a sound card.

Lyle Koehler's article on remote use of LF loop antennas for receiving purposes.

Reduced size longwave antennas by Cesare Tagliabue I5TGC and his experience on 136 kHz band.

The World of Radio Below 500 kHz by the Longwave Club of America

HFUnderground.com is dedicated to documenting longwave, mediumwave, and shortwave stations, including broadcasters, utility/military stations, pirate radio and spy numbers stations.

Useful pages of longwave operations, includes a lot of reference files, beacons list, sounds and pictures

A ferrite antenna for Low Freqencies

In the VLF portion of the spectrum it is easy to listen to the emissions created by the Earth itself. These emissions are generated by many different mechanisms and are often beautiful to listen to. Coverage on LF and MF frequencies

DK8KV Longwave information

The World of LF, by G3YXM reference site for longwave operations. Introduction to operating on 136 and 501 Khz

Experimental Longwave Transmissions from Tower Hill wayland Massachusetts Operator Name Warren, Ham Call K2ORS, Frequency: 137.7796 KHz

DK8KW Longwave Information

DF0WD DL4YHF Longwave Station include a linear transverter and antenna tuner

Active Receiving Antennas, designed for reception of shortwave, mediumwave and longwave signals and VHF/UHF signals

Low-frequency (LF) radio time signals, operating primarily in the 40–80 kHz range, are broadcast by national physics laboratories for precise clock synchronization. Transmitters like **JJY** (40 kHz, 50 kW; 60 kHz, 50 kW), RTZ (50 kHz, 10 kW ERP), MSF (60 kHz, 15 kW ERP), WWVB (60 kHz, 50 kW ERP), RBU (66.66 kHz, 10 kW), and DCF77 (77.5 kHz, 50 kW) cover vast geographic areas, often several hundred to thousands of kilometers. LF signals offer distinct propagation advantages over higher-band transmissions such as GPS. Their long wavelengths (3–6 km) enable effective diffraction around obstacles like mountains and buildings. The ionosphere and ground act as a waveguide, eliminating the need for line-of-sight and allowing a single powerful station to cover extensive regions. Ground wave propagation minimizes ionospheric variability effects on transmission delay, and signals penetrate most building walls effectively. Robust and low-cost receivers, often priced at 20–30 USD/EUR, are widely used in radio clocks. These receivers typically comprise a tuned ferrite core antenna, a receiver IC (e.g., Atmel T4227, U4223B, MAS1016) for amplification and AM detection, and a microcontroller for decoding the time signal and phase-locking a local clock. Specific components for DCF77, MSF, and WWVB are readily available from vendors like HKW Elektronik and Ultralink.

Longwave refers to all frequencies below the lower end of the AM broadcasting band at 540 kHz

This channel is all about radio listening and dxing. I will be covering frequency bands like longwave, AM/MW and shortwave. I'm embarking on my renew interest in this hobby since my childhood.

DF0WD/DL4YHF's Longwave Overview details amateur radio operations on the 135.7 to 137.8 kHz segment in Germany. The author outlines the "inofficial" European band plan, specifying segments for QRSS, TX tests, beacons, conventional CW, and data modes. Early LF activities at DF0WD began with a 20-watt CW transmitter, later upgraded to a homemade linear transverter capable of 100 watts, driven by an Icom IC706 on 10.137 MHz. The station's antenna system includes a 200-meter wire, approximately 10 meters above ground, supported by football field light-masts. Despite its length, the antenna's efficiency is noted as very low due to the immense wavelength of about 2.2 km. The author's experience highlights the significant challenge of achieving effective radiated power (EIRP) on LF, estimating DF0WD's EIRP at around 80 milliwatts based on field strength measurements from PA0SE. DF0WD/DL4YHF has successfully worked numerous countries on 136 kHz CW, including DL, F, G, GI, GM, GU, GW, HB9, HB0, LX, OE, OH, OK, OM, ON, OZ, PA, and SM. The author also mentions ongoing efforts to log contacts with CT, EI, LA/LG, and to complete a two-way QSO with Italy, demonstrating persistent activity on this challenging band.

DK8KW Longwave Information Slow-Voice, Transmitting compressed analog Audio Signals on LF

This resource details the construction and performance of a compact broadband magnetic loop antenna designed for portable receiving applications with devices like the _ATS MiniRadio_. The antenna utilizes approximately 3 meters of 0.5–1 mm copper wire wound in two turns on a rhomboidal wooden frame, measuring 50 cm by 70 cm. It connects via a modified 9:1 unun, where the primary center tap is isolated from ground to improve common-mode noise rejection. The design provides untuned operation across a frequency range from the longwave band up to approximately 25 MHz. Performance characteristics include observable directivity for noise suppression and the ability to connect directly to a radio or via a 50 coaxial cable for remote operation. The article specifies the unun's 3:1 turns ratio and its SMA output for connectivity. The methodology focuses on practical construction and observed reception quality.