SIGNALS FADING FROM SHORTWAVE BANDS

Mysterious weakening of frequencies puzzles scientists



Columbia, MD- Officials at the Federal Communications Commission (FCC) have
observed a steady deterioration in shortwave signals over the past decade,
and have kept the findings secret while they scramble to find a cause, a
government insider told a gathering of the American Shortwave Listeners'
Society Tuesday.



Measurements taken at various FCC monitoring stations show that signals are
degraded compared to ten or fifteen years ago, but only on certain
frequencies. The variation cannot be attributed to the solar cycle, which
causes signals in the shortwave bands to rise and fall every 11 years or so.



"What we are seeing is very, very strange, indeed," said a scientist with
the National Institute of Standards and Technology, which obtained the
results of a study conducted by FCC between 1989 and 2004. "It seems that
only certain very specific frequencies are affected, while others are
completely immune to the effect," she said.



Robin Ferguson, a senior member of the technical staff at NIST and
congressional lobbyist, cited three specific channels that are especially
disturbed but without a plausible explanation for the malady that affects
only these three and not the frequencies immediately above nor below them.
At the annual convention of the shortwave listeners, she described the
serious degradation that is eroding the ability of these shortwave signals
to carry communications.



"For some reason, we are measuring a definite 14 to 20 decibel drop in
signal strength as we sweep across 7.258, 10.000, and 14.230 Megahertz, just
to name a few," she announced. "It is almost as though those frequencies
were overused, that they are somehow being worn out from almost constant use
by relatively high-powered transmitters and can't support these signals-any
signals-anymore. I know this sounds crazy, but the measurements don't lie,"
she stated.



Attempting to explain the mystery in terms understandable by the layman,
Ferguson likened the effect to the deterioration of the ozone layer, "Except
it's the ionosphere that's involved here, but the real puzzle is why only
these frequencies? It's like the ionosphere knows what frequency you're on,
and selectively fades you out."



Until more data are collected, the condition appears permanent.



Ms. Ferguson revealed several more frequencies that have fallen prey to this
mysterious radio disease as members of the audience made careful note of
them. "Take a listen also on 3.885, 15.000, and 27.495 Megahertz, and you
may be surprised at what you hear-or should I say don't hear," she said.



She pointed to a section of the study where worldwide communications were
being conducted on 14.220 Megahertz, but the same signals, when they moved
to 14.230 Megahertz, a scant 10 kilohertz higher, were too weak to hear and
covered by noise. The effect has never before been observed.



Both 10 and 15 Megahertz are frequencies used by WWV, NIST's time and
frequency radio station in Fort Collins, Colorado, which operates 24 hours a
day and lends credence to the theory that the frequencies are simply wearing
out from overuse. The other frequencies have no specific user but are part
of the amateur radio service's allocations. They are used heavily by ham
radio operators to talk to their friends on the air.



"The question that is really concerning us is whether there are other
frequencies about to go south, and whether we can do anything to stop it
from happening," Ferguson said. She added that a worldwide moratorium has
been proposed while tests continue to test the 'overuse' theory, but she
said opposition would be stiff from many shortwave users who would be
affected, especially hams who use these frequencies. She stated, "I
understand it would be somewhat of a hard sell to ask them not to get on the
air, but after all, they are just hobbyists and I believe the federal
government could invoke the authority to give us the quiet bands we need to
make our measurements." In one scenario being considered, 'quiet hours'
would be imposed on hams for a limited amount of time each day.



Ferguson pledged continuing efforts to identify a cause, but warned that
budget cuts at FCC might hamper further research.