kev hath wroth:

Jeff Liebermann wrote:

Watch antennas:
http://www.c-max-time.com/products/productsOverview.php?catID=5
See the photos of the various antennas. Too bad there's no specs.

I'll grind out the field strength numbers later. I've been living in
the microwave region for so long, that I'm having problems with LF
calcs.

http://www.c-max-time.com/downloads/getFile.php?id=423
Gives dimensions,No of turns,Inductance etc.

Thanks. I downloaded that yesterday and got a file with no extension.
I eventually figured out it's a PDF file and renamed it.

The site also has a rather sketchy article on antenna design at:
http://www.c-max-time.com/tech/antenna.php
I also found the chip sensitivity somewhere at
0.5uv typical
0.8uv max
with a field strength range of:
15-20 uV/m using a 10mm x 60 mm rod.

I'm currently slogging through the NIST web pile trying to find the
historical or estimated field strengths for the left coast area.
http://tf.nist.gov/timefreq/stations/lflibrary.htm
Ah, foundit:
http://tf.nist.gov/timefreq/general/pdf/1383.pdf
Table 2.4 shows signal strength in San Diego varying from 180 uV/m to
1000 uV/m. Now all I need to do is figure out how much S/N ratio is
required at the receiver input to properly decode the time signals.

All the information needed is probably there, scattered among an
assortment of documents, but I'm at a loss on how to estimate the
actual field strength sensitivity given the rod antenna
specifications. The formula #1 at:
http://www.c-max-time.com/tech/antenna.php
has all the right parameters, but I keep getting insane results when I
try to plug in real and estimated values. Maybe some coffee will
help.

I'll work on it more during the next few daze. It should be easy
(famous last words). However, paying work comes first.

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