--- In ultralightdx@..., "farmerik" wrote:
>
> Thanks for the additional explanation, it is clearer to me now.
> What sort of loop would I wind if I wanted to connect it directly, and not use a torrid [or other] transformer?

In that case, the inductance of the antenna has to resonate directly with the varactor diode on the chip. Taking into account stray capacitance in the connecting wires and the loop itself, design for about 240 uH. This calculator should get you close. http://electronbunker.sasktelwebsite.net/InductanceCalc.html   It gives more accurate results for large air-loop coils than the one called "Professor Coyle."

73,

Jim, KR1S
http://kr1s.kearman.com/