Technical questions here, but I'm sure someone knows the answer. I recently built a 1 meter diameter three turn loop antenna that is resonated with a broadcast band air variable cap and coupling loop. By switching in the additional loops, I can get coverage from about 1- 20 Mhz, but I have a couple of questions:
1) I have a small Select-A-Tenna. This is about a one foot diameter enclosed commercial loop that has probably 50 turns of enamel wire and resonated by bb cap. It is simply brought near any AM radio that has an internal ferrite rod, or coupled if the radio has an external small loop. On AM Broadcast, this small loop seems to do better "honing in" to stations than the one meter loop I just made, any idea why? Only thing I can guess is that the many multiple stacked turns of the smaller loop offer more directionality than the 3 turns of the big loop I made (and these turns I did NOT stack, just fed through PVC pipe until I had three turns).2) Select-A-Tenna won't cover this, but the big loop I made, as I said, covers 1- 20 Mhz. However, I notice that the sharp increase in the receiver as I tune to resonance on the lower frequencies (mainly