"Anthony Fremont" wrote in message
...
Hello all,

I was playing around and saw that my junk box had all the parts so I
started tossing this together:
http://newenglandqrp.org/files/w1aw-receiver.jpg
The problem is (well I think it's a problem) is that I'm all the way down
to a 10pF cap for the crystal trimmer and the highest frequency I can get
out of it is still less than 3580kHz. Pleae correct me if I'm wrong, but
I'm thinking that the 20uH inductor is supposed to pull the colorburst
crystal high in frequency then the adjustable cap should be able to tweak
it back down. Higher capicitance does result in even lower frequency. I
made the 20uH inductor by wrapping 17 turns on an old amidon FT50-61
ferrite toroid. I don't have any way to measure the inductance, but by my
calculations it should be approximately 20uH.

You have a capacitor and inductor in series.
Capacitive reactance = -j/(wC)
Inductive reactance = +jwL
The net reactance [jwL-j/(wC)] may be capacitive (negative) or inductive
(positive).

Reducing the inductor makes it less inductive i.e. more capacitive.
Reducing the capacitor also makes the net reactance more capacitive.

You turned your trimmer all the way down to 10pF and it wasn't enough, so
try taking a few turns off the inductor.