On Thu, 07 Mar 2013 13:11:03 -0500, rickman wrote:

I understand. But this is intended to be *very* low power and I haven't
found an amp I can use that is in the low double digits uW power
consumption range. I plan to use no amp and go straight to digital.

I don't think that's possible. Unless your input A/D converter can
operate in the microvolt region, it's going to have a difficult time
dealing with the low signal levels. Fortunately, WWVB is on-off
keying with no amplitude component, so there's no incentive to add an
AGC controlled input amplifier in order to maximize the A/D converters
dynamic range. Still, you need to work with something more than a few
bits above the noise level. Incidentally, after midnight, you WWVB
delivers about 100 uV/meter or more to continental US.
http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi (Java required)
I've seen it strong enough that I can see the waveform on an
oscilloscope after a 60Khz passive filter.

As for bandwidth, the code is sent at 1 baud (1 bit/sec) which
produces about a 2Hz occupied bandwidth. Therefore, the maximum Q of
the antenna would need to be:
60Khz/ 2Hz = 30,000
before the antenna bandwidth becomes a problem.

Incidentally, while Googling away merrily, I found this on SPICE
models for a loop antenna. It's not quite in your xformer format, but
it might be useful:
http://sidstation.loudet.org/antenna-theory-en.xhtml
I won't pretend to understand what the author is doing until I read it
more carefully.

Incidentally, I used a WWVB code simulator driving a signal generator
to test my receiver:
http://www.leapsecond.com/notes/wwvb2.htm

If you're seriously into this, I suggest asking questions on the
time-nuts mailing list:
https://www.febo.com/mailman/listinfo/time-nuts

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558