On Sun, 23 Oct 2005 20:34:17 -0400, TRABEM wrote:

I am going to feed this into a quadrature front end, which has a
problem with harmonics getting into the receiver. My hope is to use
the loop as the sole tuning for the front end of the receiver, so
maintaining the highest possible Q is imperative.

Before going to such extreme measures, are you absolutely sure that
the "harmonics" are entering the receiver from the actual loop due to
insufficient Q and _not_ sneaking in through the cable shield, power
supply lines etc. or other antenna effects ?

Even if you have a single strong unwanted signal at some harmonic
frequency, taking it out with a high-Q notch filter prior to the
mixer(s) would be easier. An isolation stage (emitter follower etc.)
might be needed between the receiver loop and the notch filter to
prevent too much interaction.

Paul OH3LWR