Sunday, October 17, 2004
Last modified Saturday, October 16, 2004 10:40 PM PDT


Ryan Gardner/Gazette-Times
Chris van Rossman's television sent out a distress signal that was
picked up by an orbiting satellite.

Mystery signal traced to TV

By Jennifer Nitson
Corvallis Gazette-Times

CORVALLIS — When Chris van Rossman moved into his downtown apartment
about a year ago, his parents bought him a new 20-inch color TV with
all the bells and whistles.

The flat-screen Toshiba came with its own set of stereo speakers, a
181-channel tuner, built-in VCR, DVD and CD players, a V-chip for
parental control over content and, of course, a remote control.

Van Rossman, unfortunately, does not have cable and can only get four
channels in his apartment. He mostly watches Oregon Public
Broadcasting, which comes in clearest, and he's acquired a taste for
OPB children's programming.

Maybe the television suffered an identity crisis. Maybe it aspired to
higher things.

Whatever the reason, van Rossman's TV set sent out a cry for help. It
began emitting the international distress signal on the night of Oct.
2.

The 121.5 MHz frequency signal was picked up by an orbiting search and
rescue satellite, which informed the Air Force Rescue Coordination
Center at Langley Air Force Base in Virginia.

Such signals usually come from electronic locator transponders that
help search and rescue workers find overturned boats or crashed
airplanes. It is said that more than 90 percent of ELT signals are
false alarms, but each and every one is checked out.

Langley got on the horn to the Civil Air Patrol, an all-volunteer
auxiliary to the Air Force, and the CAP got ahold of Benton County
Search and Rescue Deputy Mike Bamberger for assistance in locating the
source of the signal.

"My initial thought was, ‘Oh, it's the airport again,'" Bamberger
said. "We've had the signals from the airport go up the Willamette
River all the way through Albany and into Lebanon."

The radio-wave signals can bounce off metal structures and rocky
hillsides. From time to time Bamberger is dispatched to the airport to
locate a transponder in a plane that has been bumped by a mechanic or
set off by a rough landing.

But this case was different.

Armed with small receiving devices, Bamberger and a group of Civil Air
Patrol volunteers determined the distress signal was coming from an
apartment building on the corner of Fourth Street and Jackson Avenue,
narrowing the possible sources down to a couple of upstairs units.

On the morning of Oct. 3, van Rossman opened his front door to find
CAP personnel in Air Force uniforms, a Corvallis police officer and a
Benton County Search and Rescue deputy looking at him expectantly. To
his credit, he did not stress out.

"I have a pretty spotless record, so I wasn't overly concerned — just
a little confused," van Rossman said. "The police officer asked if I
was a pilot or had a boat or anything. I said no, and they moved on."

After checking in with van Rossman, the group continued the search.

"We narrowed it down to a spot on the wall in the hallway," Bamberger
said. "Whatever was behind that spot is what it was."

They knocked on van Rossman's door again, and the signal abruptly
stopped.

"When he answered the door he turned off the TV, and the guy in the
hall said, ‘It just stopped,'" Bamberger recalled.

An inspection of the television confirmed it was the source of the
signal. "Their equipment was just bouncing everywhere as they turned
it on and off," van Rossman said.

Van Rossman was instructed to keep his TV turned off or face fines of
up to $10,000 per day for emitting a false distress signal.

He's not taking any chances. He's keeping the television unplugged
just in case he forgets one morning, groggy with sleep.

Unfortunately, the warranty on the TV had run out 16 days before it
started freaking out. It had already tried to escape the van Rossman
household by refusing to play DVDs a few months back, but that didn't
bother van Rossman. He has a DVD player on his computer, and besides,
he mostly just likes to watch OPB — especially "Arthur."

"I find other stuff to do," van Rossman said. "It's not too important.
It's changed my morning routine."

Alas, "Arthur" will have to wait.

Not for too long, though. Maria Repole, director of public relations
at Toshiba, is going to get van Rossman a new TV.

"We have never experienced anything like this before at Toshiba,"
Repole said. "We really value customer satisfaction, and we will
replace the television set free of charge."

Repole told Toshiba's technicians about the TV in distress, and
they'll be on the lookout in case it happens again, she said.

"They've never heard of that before," Repole said. "They don't really
have a technical explanation available. It's just very strange."

David Mandrell, squad leader for the CAP team that responded to the
TV's distress call, attempted an explanation.

"All electronic equipment creates a frequency called a tempest," he
said. "Sometimes these frequencies emit low-level signals that are
close to the 121.5 MHz signal."

Mandrell has heard of this sort of thing happening with customized
computer gear. Sometimes CAP equipment will pick up these signals, he
said, but they are usually weak enough to ignore.

"This was really strong," Mandrell said. "This was abnormally strong.
It kind of surprised us."


--------------------------------------------------------------------------------

Copyright © 2004 Democrat-Herald

Van Rossman was instructed to keep his TV turned off or face fines of
up to $10,000 per day for emitting a false distress signal.
---------------------------------------------------

and wide frequency range scanners are bound to have the local oscillator
to transmit on such a frequency if you set your scanner to a certain
frequency to listen to.

But it's always the consumers who get into trouble and never the
manufacturers who get into trouble.

wrote in message
...
Van Rossman was instructed to keep his TV turned off or face fines of
up to $10,000 per day for emitting a false distress signal.
---------------------------------------------------

and wide frequency range scanners are bound to have the local oscillator
to transmit on such a frequency if you set your scanner to a certain
frequency to listen to.


True, and some of those LO's can be quite strong, regardless of supposedly
being regulated by Part 15 rules. I had a Bearcat BC-250 scanner back when
they were new that if I set it just to the right frequency, I could open a
ham repeater three miles away with the LO.

postal97321 wrote:

Sunday, October 17, 2004
Last modified Saturday, October 16, 2004 10:40 PM PDT


Ryan Gardner/Gazette-Times
Chris van Rossman's television sent out a distress signal that was
picked up by an orbiting satellite.


"All electronic equipment creates a frequency called a tempest," he
said. "Sometimes these frequencies emit low-level signals that are
close to the 121.5 MHz signal."

Mandrell has heard of this sort of thing happening with customized
computer gear. Sometimes CAP equipment will pick up these signals, he
said, but they are usually weak enough to ignore.



What exactly are these search and rescue people listening for? Wouldn't
an emergency beacon be sending some kind of intelligent signal, like SOS
in morse code, or some kind of RTTY? At the very least, a certain kind
of modulated tone. It seems to me that if they're going to chase after
every spurious signal that pops up on 121.5, no matter what it sounds
like, that's a recipe for failure. No wonder 90% of their hits are
false positives.

Tony Calguire wrote:
What exactly are these search and rescue people listening for? Wouldn't
an emergency beacon be sending some kind of intelligent signal, like SOS
in morse code, or some kind of RTTY? At the very least, a certain kind
of modulated tone. It seems to me that if they're going to chase after
every spurious signal that pops up on 121.5, no matter what it sounds
like, that's a recipe for failure. No wonder 90% of their hits are
false positives.

If you find yourself in a heap of burning airplane parts in some valley
one day, I really hope they're still looking for weak signals on that
frequency if your ELT gets damaged. You'll hope so, too.

--
Most dying mothers say, "I love you, son," or "Take care of your sister."
Why were the last words of Kerry's mother a lecture on integrity?

I noticed the TV owner was using an antenna, instead of cable. I imagine
that the TV antenna (rabbit-ears dipole?) helped to transmit the signal in
a manner that could be received by the the satellite. If it had just been
plugged into cable, it might not have been strong enough. I bet more of
these sets get this problem occasionally, just it never becomes an issue.

Conan Ford wrote in message 23.159...
I noticed the TV owner was using an antenna, instead of cable. I imagine
that the TV antenna (rabbit-ears dipole?) helped to transmit the signal in
a manner that could be received by the the satellite. If it had just been
plugged into cable, it might not have been strong enough. I bet more of
these sets get this problem occasionally, just it never becomes an issue.

The TV in the common area, in the building I live in, also throws of a
spurious signal on 121.500. It is an old "Citizen" brand TV,
connected to a "Rogers" cable coverter.
Fred Burgess

In article ,
says...
Conan Ford wrote in message 23.159...
I noticed the TV owner was using an antenna, instead of cable. I imagine
that the TV antenna (rabbit-ears dipole?) helped to transmit the signal in
a manner that could be received by the the satellite. If it had just been
plugged into cable, it might not have been strong enough. I bet more of
these sets get this problem occasionally, just it never becomes an issue.

The TV in the common area, in the building I live in, also throws of a
spurious signal on 121.500. It is an old "Citizen" brand TV,
connected to a "Rogers" cable coverter.
Fred Burgess



My 88 S10 Blazer's factory radio/cassette did a weird thing like this.
One click down from 104.7 at 104.5, there was always an odd supposedly
dead carrier, with a slight hum, about 100HZ or so. One day I was
sitting there, bored, and was tuning around on the radio, and my dog,
who was ear splittingly loud, saw something, and started barking. I had
just tuned to 104.5, and his distorted bark could be heard clearly
through the speakers! If I really yelled, I could shout into the tape
slot and be understandable through the speakers, but I didn't have the
lung power to really drive it! That's the one thing about that dog I
don't miss..


About a year later, a friend and his wife pulled up next to me in a
parking lot someplace and we were talking and the dog went nuts, as he
did often, and I played the 104.5 "echo" for them. My friend's wife
laughed and then tuned 104.5 on their radio, and there was my dog,
yelling through their speakers too! A little testing showed the range
was about 20 ft before 104.7 started trashing it, and after 40 ft, it
was gone.

It got worse suddenly, and started feeding back all the time, if played
loudly, so I bought a used one to replace it.

BDK

In article ,
Tony Calguire wrote:
postal97321 wrote:
....
Ryan Gardner/Gazette-Times
Chris van Rossman's television sent out a distress signal that was
picked up by an orbiting satellite.
....

What exactly are these search and rescue people listening for? Wouldn't
an emergency beacon be sending some kind of intelligent signal, like SOS
in morse code, or some kind of RTTY? At the very least, a certain kind
of modulated tone. It seems to me that if they're going to chase after
every spurious signal that pops up on 121.5, no matter what it sounds
like, that's a recipe for failure. No wonder 90% of their hits are
false positives.

It's some sort of a warble tone on a carrier.

They use a transponder on polar orbiting satellites (weather and earth
sensing ones, usually) that allows the ground stations to do a doppler
measurement. Sort of the reverse of the Transit satellite navigation
system, where the timing and frequency shift of the signal allowed the
ground station to determine its position to a fraction of the meter.
The Transit system used atomic clocks, so the SARSAT accuracy would be
lower. But accurate enough to get the search and rescue close enough to
use portable direction finding gear.

Mark Zenier Washington State resident

On Mon, 18 Oct 2004 00:57:07 -0500, clifto wrote:

Tony Calguire wrote:
What exactly are these search and rescue people listening for? Wouldn't
an emergency beacon be sending some kind of intelligent signal, like SOS
in morse code, or some kind of RTTY? At the very least, a certain kind
of modulated tone. It seems to me that if they're going to chase after
every spurious signal that pops up on 121.5, no matter what it sounds
like, that's a recipe for failure. No wonder 90% of their hits are
false positives.

If you find yourself in a heap of burning airplane parts in some valley
one day, I really hope they're still looking for weak signals on that
frequency if your ELT gets damaged. You'll hope so, too.
that's one of the reasons 121.5 Mhz ELT's are going away. They are
simply beacons, and any signal on 121.5 can be an ELT,maximum power
out is 100mw. The EPIRB and PLB use a digitally encoded 406Mhz signal
with a 5 watt output, and contains the beacon ID, and can also carry a
GPS determined position as a data payload. In addition all 406Mhz
units must be registered, because 121.5 and 243 Mhz units are not
encoded, they are not registered.