Home » Uncategorized » Looking for technical input from an expert welder and/or radio engineer

Looking for technical input from an expert welder and/or radio engineer

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We need steel welds that will maintain (or strengthen) the level of VLF radio shielding provided by mild steel. My calculation is that the production-grade steel I’ve sourced out at 50/1000 of an inch, will provide at least 10 skin depths for a 10 kHz wave. This will massively reduce the signal strength. My suspicion is that if VLF radio is found to be the cause, then the culprit frequencies might be in the range of 8-16 kHz.

So what exactly do we need to know before we start welding this stuff? Can anybody find a reliable source for information on this topic? I’ve searched for hours and all I can find are references to my own blog or irrelevant topics.

Perhaps we need a radio engineer to weigh in, as well as an expert welder.


3 Comments

  1. jimvandamme says:

    Is there a drawing of your box somewhere? Are you going to overlap or butt weld the panels? Most importantly: how are you going to seal the door? Ventilation? Penetrations? Wires going in and out?

    • I’m looking at 3ft by 3ft x 7ft. Asking for input on welding. Sealing the door will depend on the technical advice I’m given. No wires needed. Ventilation: that depends. First things first, the welding information.

      • George G. says:

        I strongly recommend overlap weld.
        Your specified frequency range (8 to 16 kHz) safely falls within the envelope where the current density has diminished to 1/e of it’s value at its surface (assuming your calculations of 10 skin depths are correct).

        Should a fault occur during welding, it is not hard to see that a butt weld would be inferior to an overlap, simply because an overlap provides extra thickness at the potential weak points, and extra thickness means extra attenuation.
        Go ahead and weld, it’s not as critical as you think.

        By the way, have you considered electrical earthing? It would be a very easy task to attach an effective earth probe to your box via a series- connected switch. Play with the switch, incorporate it with your tests, i.e. earth ON, earth OFF, blind tests, of course. How I wish I was there!

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