Subject: [Lowfer] Growling audio on MWBC signals
Date: Wed, 22 Dec 2010 14:31:02 -0700
From: "C. Turner" <turner@ussc.com>
Slightly OT, but interesting nonetheless:
Some weeks ago I happened to tune in our local 69 horsepower (formerly)
"clear channel" AM radio station (1160 kHz - KSL) and upon listening to
it in SSB mode using exalted carrier methods, I heard a rather obnoxious
growling on the audio that disappeared when "normal" AM or synchronous
AM techniques were employed.
Upon inspecting the carrier, I noted that there was a pair of 16 Hz
sidebands responsible for the "growling." Curious, I asked the
engineer, Randy, K7SL - who I happen to know - and here is an excerpt of
his response:
"16Hz is a low speed data stream used to send messages to warranty
receivers. These guys are battery operated 10 year lifetime receivers
that attach themselves to things like Baby Cribs, Saws, etc. These
receivers set off alarms if a factory recall happens. They then give
details for the recalls. The data also contains clock correction
signals for home user clocks. The clocks currently using WWVB don't get
a good enough signal inside noisy environments and the 50kW signal from
KSL and other Clear Channel stations cover the the US better.
"Currently the signal ... is just a test signal that repeats itself.
If [one] looks at night on other strong AM stations [you] will see
similar signals. There are other uses for the signal, but I don't
remember them right now. All I know for sure is that it eats up a lot
of transmitter power. Of course any 1/2 db added to the modulation
looks like it is stealing all the power when you look only at modulation
levels around 95 to 100% (chuckle).
"A word of warning. If you walk too closely to one of these receivers,
it might un-attach itself from where it is and jump to the back of your
neck and re-attach itself to you. It will then give Aliens control of
your mind and you know what happens from there. [I saw this on TV so I
know it is true]"
So there.
I wonder how long it takes before conspiracy-minded people consider this
to be a means of mind control?
(Never mind... too late!)
73,
Clint
KA7OEI/CT
----------------
Jon-FL wrote:
Below is a messgae you wrote.
I'll like to share is with the members
of the IRC channel #WUNclub, and thier e-list (UDXF@yahoogroups.com).
Any objections?
---------------
Hi Jon,
Sure - no problem.
I might add that I've observed the same data on 1040 (WHO) and 1110
(possibly KFAB) while another on the LF list (Steve R.) also spotted it
on 850 (KOA).
After receiving his email, I recalled having read something about it in
the trade rags, but it would be interesting to know the "official" name
of this service as that would make it a bit easier to research and the
initial stabs at Google searches haven't turned up anything: I've not
had the opportunity to ask Randy.
73,
Clint
...........................
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Topic: Growling audio on MWBC signals (Read 2211 times)
