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Posted by Ed, KI6R on November 30, 2024 at 05:08:18.
In Reply to: LW receiver suggestions posted by Ed Barboni on November 29, 2024 at 19:26:37.
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Most modern solid state receivers don't do well on VLF. Your R75 is good on HF so you might try finding a VLF-to-HF upconverter. An upconverter will typically convert 0-500 kHz up to some HF range like 3.5-4.0 MHz. This allows all the performance features of an HF radio to be used at VLF. A properly designed converter will have good sensitivity at VLF. Search for "VLF upconverter" on the web and you may find some candidates. It looks like hamcrafters2.com has a candidate. The other thing to try is to improve your receive antenna. Longwave antennas need impedance matching to the 50 Ohm input impedance of your receiver. One way to do this is to use an active amplified whip antenna. There are many of these for sale on the web. You would want one that has good specifications in the VLF range. If you try to use a longwire antenna you will need a VLF antenna tuner to match the impedance of the wire to 50 Ohms. I'm not aware of any VLF receive antenna tuners available but one can be built from junkbox parts. Some of the new antenna analyzers now cover the VLF range so one can build and test/adjust a homemade tuner with the analyzer. Good luck with the VLF & 73. Ed, KI6R
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