Bill Hennessy wrote:
Is their a set rule on how meny turns of the antenna coil is to the
tuneing coil? And would it depend on if you wind it over or next to the
tuneing coil?
Yes, it makes a difference if it's over vs. next to the tuning coil,
because your coupling will change with distance.
No there isn't a set rule (or shouldn't be) -- you should design your
transformer for the desired input impedance of the devices you're going
into, the intended input impedance of your radio, etc., etc.
Ideally you'd decide on what kind of noise & intermodulation performance
you wanted from your set, decide what impedance your 1st stage should
see, and design your antenna coil from that.
Realistically you can just look for similar radios to the one you're
wanting to build and use an average of their input coils as a starting
point, then dink with it if you feel motivated.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com