We had a strange 2m interference incident occur yesterday around Chicago.
A group of us were on the Lucent Naperville repeater on 145.17 MHz around
7am local time. A mobile station that was near Argonne (Argonne labs)
reported that he was hearing what sounded like very strong power line noise
(he complained about the power lines has was passing at the moment). At that
point a big truck pulled up next to me and I started hearing similar noise
-- I just figured it was the truck's injectors or engine control system
making the noise. However, the truck pulled away and the noise didn't. At
this point, I was in Hoffman Estates which is probably about 35-40 miles
north-northwest of the station in Argonne.
Also, at this point in time a fixed station in Plainfield (farther south
than Argonne) was receiving the interference so strongly that he could no
longer copy the 145.17 repeater. He said he was receiving the repeater at
S-9, but the interference was about S-7. This operator described the
interference as sounding "similar" to the control channel of a trunking
system.
I finally got into the parking lot at my work QTH in Hoffman Estates and
played with the VFO a bit. The noise also sounded like strong power line
noise to me. It seemed to be amplitude in nature since it was tickling the
S-meter but was not breaking the squelch. It seemed to be centered on and
peaked around 145.17 MHz, but could also be heard as low as 145.15 and as
high as 145.19.
The station in Argonne originally heard the interference at about S-3, but
continued to listen to it as it appeared to slowly fade away.
When discussing the issue this morning on the radio, some of the group
mentioned that there are some unusual aircraft (military and otherwise)
flying in the area in preparation for Chicago's Air and Water show this
weekend.
Any ideas? -Michael, N9BDF
PS The "Amateur Radio Emergency Communications Consistency Act" (HR 1478)
and the "Amateur Radio Spectrum Protection Act" (HR 713 & S. 537) are in
Congress. Please contact your Congressmen to ask for their support of these
bills! See the following ARRL link for details:
http://www.arrl.org/govrelations/ <http://www.arrl.org/govrelations/>
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