I have been able to use the Quantum QX Loop to null the Wobbler signal
and achieve direction finding on the sources. The image above
shows the location and specifics of stations that have been identified
as sources of the Wobbler. As the opportunity presents itself,
other stations experiencing the Wobbler will be similarly DF'ed if
possible, and the results presented here.
Source: Two Radios - The question
has been raised if there might be one Wobbler affecting the several
frequencies where the signal has been detected. To answer this I
used two radios, tuned to two different frequencies both experiencing
the Wobbler, each radio recorded on a stereo MP3 channel.
The radios used an injected BFO to enhance the Wobbler for easier
detection. The two BFO frequencies are slightly off with each
other making the two signals distinguishable. Use of the stereo
balance control will allow listening to one or the other recording
separately.
Two Wobblers - Another proof of
multiple Wobblers is this recording of two Wobblers heard on a single
radio, both on the same frequency and clearly not in step with each
other.
From these samples it seems reasonable to conclude the
Wobbler is not a single signal, but clearly mutiple signals.
Extreme Wobblers - The
following three MP3 recording samples demonstrate the extreme nature to
which the Wobbler can rise. These recordings include audio with
no special processing to enhance the signal, it is just the raw power
of an enflamed Wobbler you are hearing. These recordings are
stereo, however, and also include processed audio. The right
channel is unprocessed audio, the left channel has been processed to
suppress some of the background noise. Use your audio balance
control to select the channel to which you wish to listen.
Drawing on my investigations and a wealth of
suggestions, observations, and theories from members of the IRCA and
NRC radio clubs, I have summarized the consensus, presented below for
your review. The hunt continues though, and these preliminary
conclusions could easily change. To draw your own conclusions,
review the many radio enthusiasts' entries found on the Comments
page. If you come to a completely different conclusion, or if you
just have a new twist, please let me know by sending email from
the Contents
page.
Location - The
direction finding results from here in southeast Florida so far point
to an origin of the Wobbler at Cuban broadcast stations. Most DF
results from other locations also point toward Cuba in general.
Where DF'ing has pointed elsewhere, the results are either uncertain or
can not be explained. These results should not be dismissed, but
for now, the preponderance of evidence is that the Wobbler is a product
of Cuban broadcast stations.
Cause - There have
been several theories put forth as to the cause of the Wobbler.
Jamming, transmitter malfunction, power grid instability, intentional
annoyance, and atmospherics all have been suggested. Since it
seems to originate at more than one Cuban broadcast station rather than
some outside source, jamming - at least of the Cuban
stations - seems unlikely. The possibility it is jamming by
these stations is equally unlikely since it is their own signal that is
most affected. If malfunctioning transmitters is the cause, then
there are several bad ones, and their problems come and go during the
day. Atmospherics would seem to be eliminated as a source.
I can make this assertion since it was I who offered this theory.
Intentional annoyance can only be eliminated if some other reason is
found to be the cause, but even for Castro, seems unlikely. So,
for lack of any better candidate, and because it is the most popular
theory, power grid instability seems to take the lead as most likely
cause. For this to work it probably also has to be coupled to
particular transmitter types, since in a given region, some stations
have problems and others do not. And to further muddy the waters,
it could also involve some degree of transmitter malfunction, at least
in the form of misadjustment. Hardly a definitive answer, but
more than what was know when this mystery began.
But - There are
still uncertainties, maybe even some other possibilities so far not
considered. Over time even what seems to have been established
may prove inaccurate or invalid. So the hunt goes on. More
Df'ing, more logging of reception reports, and more thought is the
order of business.
Investigations into this phenomenon continue. New Wobbler results
will be posted here as they are obtained.
