You can eliminate the transformer by having more turns
in the loop.   But you'll probably find when you do the
arithmetic, that it is cheaper to have fewer turns (or
one turn) and a transformer.   Also for helping with
balance and isolation the transformer is useful even
if you didn't need impedance increase.  You may also
find a lower thermal noise floor with few turns and
a transformer, compared with the same loop area and
many turns.

I use 3 turns (mains cable) of about 20 square metres,
an audio transformer with ratio 1:12.6 and LT1028 preamp.

Modeled fairly well in this example

 http://abelian.org/lcnetgen/ex6.html

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Paul Nicholson
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