From: bill@hacktic.nl (Bill Squire)
Newsgroups: rec.radio.amateur.misc
Subject: Earthquake prediction?
Date: 27 Jul 92 13:50:23 GMT
Organization: Hack-Tic Magazine


The post by Jack C. Lockhart of UC Irvine on the observed shifts on AM
radio has me a little puzzled.  If AM broadcasts appear to shift upto and
over a full percent, I am very surprised I was able to use the carriers of
KFI and KNX in LA and also KSFO in SF to calibrate my frequency measuring
equipment while working on a FDM telephone carrier project.  I have
understood these three stationd have an atomic based frequency source,
along with Loran C at 100kHz.  Since Loran C, and USA AM stations all
divide down to 10 kHz, doing this at the time confirmed I was able to
receive the signal and phaselock it, divide by N and compare the 10kHz from
two sources and find there was absolutely no continuous phase change noted
between any two.  (From Sunnyvale Ca. the two LA stations would phase shift
due to changing distances the signal travelled)  If this is a joke, then I'm
a sucker, if its not a joke, I'm a real sucker, the signals at 100kHz,
560kHz, 640KHz and 1190kHz (think thats KNX) all shifted an exact percent
amount!  I don't think so, since the calibration was re-checked on another
evening, and the counter was still correct.  Somebody please do this
themselves (we don't have many earthquakes in this part of Europe) and let
everybody know.  I refuse to believe this and I think it was made up like a
tabloid story at this time.

To make my setup, it is very simple.  Take a large ferrite rod and suitable
variable capacitor.  Amplify the preselected signal to a level that will
lock the PLL system of your choice. (I used a MC1496 as a phase detector and
a commercial function generator with FM input as my PLL) If you want, use
another phase det. and quadrature signal from the generator to demodulate
the AM signal and provide AGC to the preselector amplifier.  The buffered
signal from the PLL can be used to drive your frequency counter.  If you
use the above stations or WWV, I sincerely believe any drift you see is
your counter!  Enough is enough.

Oh yea, just before I left California (a little after the nice ride from
the Santa Cruz mountains)  I heard an interesting report about signals in
the one hertz range going through great fluctuations just before that fun
quake.  (it wasn't fun being almost on top of it at the time, but as an
afterthought I REALLY enjoyed it since almost no one got hurt and damage
was very little)  This aspect of prediction sounds more like science.  It
makes sence to me that extreme ELF might be produced from an assorted
mixture of piezo electric, chemical and other sources miles underground as
a result of great changes of stress below.  Of course higher frequencies
will be produced, but only the lowest ones will get thru the kilometers of
rock below the soil.  If any of you are interested in this and have enough
property (and money) to make a 'proper' antenna for 1Hz, I love to hear more.
I would suggest at minimum, to dig a ditch about 2 meters deep (ALOT OF
WORK!) and form a circle atleast 1 kilometer in circumference.  Bury as many
turns of suitable wire as you care too (this is ALOT OF WORK too!).  As far
as receiving you MUST of course lo-pass filter and notch at both 50 and 60Hz
(yes both are strong ANYWHERE on the planet) amplify with the best 1/f opamps
available (OP220's and OP221's are good choices).  This signal would best
be digitised and then analysed on a computer.

The above should be a nice summer project and a way for the otherwise bored
UC students to drink beer and do something very productive, that may even
save lives in the future!

                                                        Bill