VLF (Very Low Frequency, 3–30 kHz) behaves quite differently from higher-frequency radio because the wavelength is enormous (10–100 km). Under polar ice caps, two main propagation situations exist: These give…
Click on link below to download: https://www.astronomy.me.uk/wp-content/uploads/2026/03/John-Berman-SID-Presentation-BAA-VLF-Meeting-160326.pdf
At 20 kHz you’re really designing a resonant system, not just adding a tuner box. For your kind of radio astronomy / interferometry work, the most practical approach is a…
Short answer: yes—but not in the way you’re probably expecting. 🚫 Off-the-shelf ham tuners: no All the usual amateur ATUs—like only cover roughly 1.8–30 MHz (HF). Even the “wideband” ones…
For a VLF loop antenna used to monitor Sudden Ionospheric Disturbances (SIDs), the received signal strength mainly depends on the loop area × number of turns, not simply the total…
70cm aerial for UKRAA 23 kHz receiver: The 134cm LRO Aerial:
Click on link below to download – provided as ZIP file – unzip this into your Spectrum Lab configurations folder: https://www.astronomy.me.uk/wp-content/uploads/2026/03/LRO_VLF_Config_works-with-134cm-aerial-LRO-PC-10-210226@1800.zip
New process to clean up hydrogen line data, removing RFI. https://github.com/AP-HLine-3D/HLine3D/blob/main/JAVA_HL3D_mX%2Bb_RFI_V2.2_08Mar26_IFAvg2csv.jar start with zero frequency width and gradually widen.
A SID stands for Sudden Ionospheric Disturbance. It refers to a rapid change in the ionosphere caused by intense solar radiation, usually from a solar flare. These disturbances are commonly…
Yes — there are several practical disadvantages of using a SAWBird H1 (or similar surface-acoustic-wave bandpass filter) compared with a cavity filter in RF front-ends, especially at VHF/UHF, narrow-channel, or…
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