Rockin' Rollin' & Radioin'

In light of last week's earth-shaking events in California, I thought it would be appropriate try to generate some interest in performing basic research into a radio phenomenon that might be of great benefit to society in general.

My father, W6VPV, was a very dedicated ham. Dad would come home from work every night, and as soon as dinner was over, he'd disappear into the 'radio room', not to be seen again until the next day. Dad was primarily a CW man, and he spent the vast majority of his time tuning the lower HF bands, just looking for interesting signals.

Dad would often call my brother and me into the radio room of our house in San Jose, to listen to signals he'd found. In early 1971, he called us into the shack one evening to hear something strange.

Dad pointed out that all of the signals from Southern California had a warbling 'echo' - multipath distortion. These signals all sounded like Europeans coming over the North Pole at night - watery with ringing. This was very odd - I'd never heard anything like that before on LA-area signals . Dad made a special note of it in his logbook. We heard this warbling on all bands from 160 through 20 meters, as I recall.

The following morning, we all sat around the breakfast table, and someone turned on the TV. We were greeted with the news of the terrible Sylmar earthquake, that happened only a short while earlier! At this point Dad told us the rest of his story.

In years of listening on HF, Dad had heard similar things before. He heard it on signals from Alaska in 1964 the night before the giant Good Friday quake. He had heard it on signals from Central America prior to a major quake down there.

We all thought Dad should pursue this, and report it to the authorities. But, at that time, Dad's work required a very high level security clearance, so the last thing he would ever do was to call attention to himself. As far as we know, he never pursued it.

I've put this up on various bulletin boards and Internet discussion groups in the past, and I've received some interesting responses. I got lots of reports about 'ringing' radio signals immediately prior to and during the Loma Prieta earthquake years ago. There are stories on the net about research done by the Chinese and others into low-frequency radio signals that seem to be precursors to some large quakes. Perhaps these low-frequency signals somehow influence the way that the HF signals are propagated, resulting in multipath distortion.

Here are some interesting URL's about research into radio earthquake 'precursors': http://www.riken.go.jp/lab-www/library/publication/review/html/No19/19-64/19-64.html

http://www.copernicus.org/EGS/nhess/1/nh1/99.pdf

Note that the second article, above, discusses signals observed at a number of different frequencies, including "initial observations at 18Mhz.".

I've always thought that hams would have the unique ability to monitor for this phenomenon. We are the only ones with diverse HF stations spread throughout the areas where earthquakes are common.

I'd like to see this pursued as scientifically as possible. I am not interested in wasting my time or anyone else's on another "In Search Of…" episode. But if we can put together just a little real documentation, I have no problem with taking this to the authorities or the academic community. But I need more than 35-year old memories!

What can you do? Be active and listen a lot. Listen for signals from earthquake prone areas. Make notes of any signals with multipath distortion on them - they will have a 'ringing' or echo effect. Then, check the news the next day to see if there were any quakes in the area of the signals you monitored. There are a number of websites that show the locations of recent earthquakes.

If you think you have observed this, please email me! I will act as a collecting point for these reports.

The reason I started to write this article is because I was listening a week ago last Sunday to 80-meter signals, trying to record some for an upcoming radio class. I was listening to a strong signal with a W6 callsign, and I noticed a weak, but very noticeable 'echo' on the signal, that reminded me of this.

I was very surprised the next day, when the big earthquake struck Central California! I suspect this means that the phenomenon can be observed even from a great distance away.

If your spouse gives you grief about spending so much time on the air, just explain that you are monitoring for earthquakes!

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