[Bazz4CQJ]

Firstly, I think it is best to completely separate all discussion of receiving loops and transmitting loops. The complexity of transmitting loops is so much greater, perhaps in part because of the very high voltages that come in to play?

Re LZ1AQ; yes I think his site is a "Must see" source of info. I think he published his first designs back around 2011 and now he runs his own business selling them. His 2011 design may well be an easier amplifier to build than a Wellgood.

Re the material for the loop; my understanding is that is that you want to try and keep the inductive reactance of the loop to a minimum, and this is especially true as you go north of 2MHz. The reactance is directly proportional to the inductance and the inductance of a single multistranded wire is about 5 times higher than a 1" tube. The choice of material can also affect the RF resistivity. Other materials options beside tube include using the braid of "monster" coax cable.

Of course, even if we separate the receiving loops from transmitting loops, there's still the issue of whether to choose resonant loops or non-resonant loops. The net is full of info...it's picking out the wheat for the chaff that's a problem.

B