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"Mother of all jamming stations" continues to plague 40 meters
Published by permission of The ARRL Letter, Vol. 20, No. 01, January 5, 2001
For some months now, regular users of the 40-meter band have been plagued from time to time by strong, very broad, frequency-hopping signals that somewhat resemble a slow-scan TV transmission. The signals, it turns out, originate from jamming stations in the Middle East.
"We know exactly what this is," said ARRL Monitoring System Coordinator Brennan Price, N4QX. "This is a very high-power Iraqi jammer of a very high-power Iranian shortwave broadcast station."
The loud buzzing signals have been heard on the 40-meter CW and phone bands and have even been "spotted" on packet. The jammers occupy about 10 kHz of spectrum.
Price says the shortwave broadcast station involved is The Voice of the People of Kurdistan, transmitted via The Voice of the Islamic Republic of Iran facility in Teheran. "The Iranian station has a daily transmission on 7100 kHz from the same facility, and Iraq has jammed that one also," he says.
Price explains that the Iranian station--which broadcasts anti-Saddam Hussein propaganda, hence the jamming--jumps frequencies several times each broadcast in order to avoid the jamming. Unfortunately for 40-meter users, the Iraqi transmissions follow. This results in a situation where it's hard to predict when the jammers might show up on a given frequency block or how long they'll stay.
Price said that neither station is transmitting where it is supposed to be. "The Iranian and Iraqi telecommunications administrations
See "Mother",
next column
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"Mother" from column 1
have been advised of this," he said.
Price says that such "politically motivated" intruders typically don't disappear until the political situation changes. "The 'woodpecker' went away when the Cold War did," he said. "This one will probably not go away until Saddam Hussein does."
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Jamming from 1st column
that the object of the jamming is an Iraqi pirate station--which several SWLs identified as The Voice of the Mojahadin--broadcasting in Persian into Iran on various 40-meter frequencies as well as in the Aeronautical Band. The pirate station operates on a specific frequency--or frequencies--until it's spotted by the Iranians, who then attempt to jam the signal. The broadcaster then hops to another frequency to avoid the jamming, which explains why the jammer will suddenly pop up on a frequency for several minutes at a time and then disappear.
IARU Region 2 Monitoring System Coordinator Martin Potter, VE3OAT, concurs with the ARRL's latest information. He says the jammer often puts "a thundering great signal into my antenna."
The jamming signals are broad and noisy. They typically land on multiples of 10 kHz and occupy some 10 kHz of bandwidth.
The Iranian and the Iraqi governments are reported to have ignored complaints by the US and the United Kingdom. Price says that in light of the strained relations between the US and both Iran and Iraq, there's not much hope that the problem will be resolved anytime soon.
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Who's jamming whom? Getting the story straight
Published by permission from The ARRL Letter, Vol. 20, No. 2, January 12, 2001
It turns
out that the 40-meter "wobble-and-buzz jammers"
heard by many in the US over the past year or so are Iranian
stations that are attempting to block Iraqi stations--not
the other way around as recently reported (see "Mother
of All Jammers Continues to Plague 40 Meters" in The
ARRL Letter, Vol 20, No
1). Several members of the monitoring community had questioned
the earlier ARRL report,
which was based on information from typically reliable sources.
"I began to doubt our information on January 8, when I received second-hand reports from SWL DXers that the jammer and jammee were backwards," said ARRL Monitoring System Coordinator Brennan Price, N4QX. "Further investigation confirms their reports."
Larry Van Horn, N5FPW, the assistant editor of Monitoring Times, forwarded several SWL reports to ARRL that suggested the jamming signals definitely were coming from Iran and already were well-known within the monitoring community. SWL reports indicated that the signals typically operate in the range from 7020 to 7090 kHz.
The ARRL's sources said this week
See Jamming next
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