>From the ARRL Letter, Vol 18, No. 40, October 8, 1999.
There have been quite a few posts on this subject. For those of you who do not
receive the ARRL Letter...
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WHAT'S THE BUZZ?
Efforts are under way in the US and Canada to identify the source of what's
being described as a loud and broad "125 Hz buzz" that's been showing up on
the 80-meter band. The ARRL Monitoring System has requested FCC assistance
in tracking down the harmful interference, which has been audible primarily
in the US Northeast. The League also is working with Radio Amateurs of
Canada. The annoying buzz frequently has been heard on or about 3.5 MHz.
It's also been monitored in the vicinity of 3.6 and 3.7 MHz. Sometimes, it
transmits for hours on end, other times for relatively brief periods of a
few seconds or minutes.
Audible over a bandwidth of more than 30 kHz, the signal has become an
increasing irritant to amateurs over the past few weeks. ARRL member Dave
Bowker, K1FK, in extreme northern Maine reported hearing the signal in
mid-September. "The interference is a square-wave modulated signal which
totally destroys any communications possibilities (20 kHz either side of
3.500 MHz with its 'buzz saw' characteristics," he reported.
Bowker's direction-finding efforts determined the signal was coming from the
north northeast "from over the polar region." At least some FCC staff
members believe the signal originates in Canada. An FCC staff member said
this week that the Commission has been investigating the emission "for a
couple of weeks" as a result of a complaint from an aeronautical weather
station that broadcasts at 3485 kHz. The staff member said the signal
appeared to come from Newfoundland and said the FCC was in contact with its
Canadian counterparts at Industry Canada.
There have been suggestions--unconfirmed--that the signal might be the
result of a system being operated by the Canadian military. Military
authorities North of the Border reportedly have said they will look into the
complaint. Other as-yet-unconfirmed information suggests, however, that the
signal was not of Canadian military origin at all nor even from Newfoundland
but might be coming from Europe.
"There are certain risks in trying to DF any pulse signal that may not be
transmitted mainly in the direction of the observer," says IARU Region 2
Monitoring System Coordinator Martin Potter, VE3OAT. Potter says bearings
obtained may actually be on the "returned signal" from reflection and
scatter points along the transmitted signal's path--either in the ionosphere
or on the ground or ocean, or both. "So it may be premature to conclude that
the transmitter is in Newfoundland, especially if reception is only by
skywave, without taking special measures while obtaining a bearing," he
said.
To add to the mystery, ARRL member Paul Veal, N0AH, in Wyoming--in a
TowerTalk reflector posting earlier this month--reported the signal was
appearing every morning at 1300 UTC on or about 3795 kHz. He said the signal
appeared to coming from a northwesterly to southwesterly direction.
Additional reports and observations are welcome to ARRL Monitoring System
Administrator Tom Hogerty, KC1J, thogerty@arrl.org.
-------- End Quote from ARRL Letter ---------
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73, Guy
k2av@contesting.com
Apex, NC, USA
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