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Questions tagged [vlf]

Very Low Frequency is the frequency range 3-30 kHz.

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1answer
84 views

Need a ferrite suppression material for choking 15 kHz to 60 kHz

Electric fence RFI is ruining reception on our ELF lightning receivers, and we need a material to place around neighbors' fence wires to suppress the noise being radiated. Preferably, a split bead, ...
1
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1answer
631 views

Designing VLF antenna

I was doing some research about the relation between wavelength and antenna size and shape. I was mostly interested in 15KHz rf range. Based on my research I found the following: A squarish shape ...
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1answer
97 views

How to explain a frequency pic at 1.5 kHz?

I have a pic in the VLF band at 1.5 kHz. What would be the origin of this peak? The graph was obtained by running display_qt in Linux from a laptop.
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2answers
205 views

Rudementary Impedance measurements for VLF antenna system

I am looking for ideas to improve my Impedance measurements I perform on my VLF antenna system. Due to circumstances my VLF experiments are usually "on location / in a field" so I do not have the ...
2
votes
1answer
113 views

Ferrite Rod Price Differences

We are trying to make a VLF geophysics device for our graduate project and we need two ferrite rod antennas (desired length is 6"). Searching on the internet, we have found two ferrite rod suppliers. ...
5
votes
2answers
210 views

What are the continuous transmissions at the lower end of the spectrum?

I'm fairly new to amateur radio, and I've been using a web-based SDR tool in addition to my own radios. Using this SDR tool shows a lot of activity lower down on the spectrum, such as this: When I ...
6
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1answer
643 views

Why are there no amateur allocations in the LF and VLF spectrum?

Amateur radio enthusiasts have slices of spectrum at every magnitude of spectrum MF and above, but in the US none are below MF. Why are there no spectrum allocations below 160M?
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2answers
1k views

Does increasing the number of turns on a loop antenna decrease frequency operation?

Lets say I want to make a VLF loop antenna for a Sub AM radio band. I don't want a full wavelength because that would be a humongous antenna. Would I wind more turns of wire to decrease the frequency ...
3
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1answer
177 views

How can I communicate with VLF ground waves [closed]

I willing to try really hard on working with Very Low Frequency waves to get a signal through the earth a few Km. How can I go about putting a signal at the frequency (probably near 10 kilohertz) ...