A custom design square loop antenna for VLF detectors

[Digdeeper2]

Hi,

I was wondering if a custom design square antenna will help to increase detection depth of a VLF detectors? Would a square loop antena work with VLF detectors?

I'm mostly looking for maximum depth than discrimination.

Thanks,

 

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[DizzyDigger]

Gotta ask..why do you think a square antenna would allow for deeper
penetration?

The only way to find out would be to design the antenna, then test it
for the radiation pattern in a proper antenna patterning chamber.

 

[Digdeeper2]

Gotta ask..why do you think a square antenna would allow for deeper
penetration?

The only way to find out would be to design the antenna, then test it
for the radiation pattern in a proper antenna patterning chamber.

Hmm, I've only seen big square antennas being used with PI metal detectors.

 

[TheGreenBoy]

Theoreticaly yes, practicaly the game ends with the size of coils you can see on a "relic striker" or similar detector. The VLF needs at least 2 coils in a probe, a tx and rx coil. A tx coil is powered continuously in contrast with PI, where short pulses are used. If you double the probe diameter, and thouse the Tx coil, the magnetic field generated will strach further away, but the field density will be at laest 4 times weaker measured at the same point. Thuse, the 4-times more energy would be required to power it. It is the same story with PI, only the short time energy bursts caries the story a bit further.

 

[Digdeeper2]

Theoreticaly yes, practicaly the game ends with the size of coils you can see on a "relic striker" or similar detector. The VLF needs at least 2 coils in a probe, a tx and rx coil. A tx coil is powered continuously in contrast with PI, where short pulses are used. If you double the probe diameter, and thouse the Tx coil, the magnetic field generated will strach further away, but the field density will be at laest 4 times weaker measured at the same point. Thuse, the 4-times more energy would be required to power it. It is the same story with PI, only the short time energy bursts caries the story a bit further.

Thanks for clarification.

 

[Carl-NC]

I was wondering if a custom design square antenna will help to increase detection depth of a VLF detectors? Would a square loop antena work with VLF detectors?

Square will work, but won't give you any more depth. Perfectly round is the ideal shape for max depth. Square also has tight corners which produce small high-density fields, which increase lift-off effect. This translates into noisier ground performance.

 

[DizzyDigger]

Digdeeper, here is a tutorial (.pdf) that will give you some very good insight
on the various antenna designs and their typical radiation patterns.

https://www.cisco.com/c/en/us/produ...essories/prod_white_paper0900aecd806a1a3e.pdf

It's not overly technical, but those unfamiliar with antenna design and testing may
need to look up a few words.