H-field pre-amplifier placement inside loops?
#1
Can the H-field pre-amplifier PCB be placed 'inside' the loops of a 3-loop H-field antenna?
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#2
That is exactly what I have done, and my station works quite well. I don't know if there are any complex reasons why this might be a bad idea.
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#3
The H-field is all balanced so any common mode signals, from possible re radiation from the loop(s) will get cancelled out.

I'd caution against three loops or indeed two loops an a single fixed frame. If you discover you have a local source of interference and you use the null of one loop to eliminate it the other loop will get the full benefit of the interference. Being able to independently orientate each loop may be very useful.

I have two VLF transmitters close by, fortunately within 30 degrees of each. One loop can be aligned to virtually eliminate the interference from both transmitters. I did have the other loop fixed at 90 degrees, all that got was 100+ mV of interference. It's now on a separate frame and can be orientated to strike a balance between the interference level and not having the same orientation as the first loop.
Cheers
Dave.

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