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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.

The first one:

Stormwise

2000u Monster Ferrite Rods

Length: 6 inch

Diameter: 0.845 inch

Price: $24

And the second one is a local supplier:

Length: 3.93 inch

Diameter: 0.314 inch

Price: $1

We do not have experience and knowledge about antennas and their materials. The guy in the local supplier said that you can butt splice the coils to get 150 mm length and that diameter only affects the number of wire turns.

Is the advice accurate? Can you explain why the price is so different? Might it be due to the material quality or something else?

Kevin Reid AG6YO
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ecabuk
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1 Answers1

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"Ferrite" is not a fungible material. There are many kinds of ferrite materials, each with very different properties. To make a comparison, you need the material datasheets, which answer questions like:

  • What is the relative permittivity?
  • What is the loss at the frequencies you intend to use them?
  • What is the Curie temperature of the material?

You can see How does one read a ferrite datasheet? for an example of some of the parameters listed on a typical datasheet.

Without datasheets for each material, it's impossible to make any fair comparison of price between the two options. It may even be that the material is not suitable for your application.

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Phil Frost - W8II
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