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?

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.

matt weber wrote in message . ..
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.


And these REGISTERED units have the contactee's name and home phone
number. Within literally minutes, say like the Coast Guard, is calling
that person's home phone number to find out what the deal is.
Unfortunately, sometimes all they can get is the spouse of the
registered owner, and he or she don't have the faintest idea. All they
know is their husband or daddy does fly on the company plane once in a
while and he's away right now. But in the long run, it DOES save a lot
of needless searches for errant transmissions. And a heavy fine to
boot if set off fecklessly with no confirmation. 15 to 20 thousand
dollars per occurrance, if I remember correctly. If you do set one
off, especially an aircraft one, call 1-800-WXBRIEF and that number
will rotate your call to your nearest Flight Service Station to cancel
the inquieries and explain your situation. The days of CAP members
tramping all over the neighborhood all day searching for an accidental
trip are hopefully over.

And a heavy fine to boot if set off fecklessly with no confirmation.

Now, that's a funny thought -- a distress signal set off fecklessly.

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

(Mark Zenier) wrote in message ...
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

I bought an older (circa 1970) 121.5 ELT at a auction several years
ago.
And this unit had no modulation. Simple oscillator, followed by a
trippler,
a driver and a power amp. It had several shock switches in parallel.
This unit was designed to be clamped to the inside frame.
I always wondered just how well it radiate from the inside.
I have heard three ELTs, two hard landings, I live about 6 miles from
Lexington BlueGrass airport in Lexington Kentucky, and one was a
accidental trip in a local neighborhood. All three had a distinctive
"Wail" that is hard to discribe. I keep one scanner tuned to 121.5,
243 and some other hot freqs, and one Saturday morning I heard the
wailing of an ELT, and after 30 minutes, decided to go find it. With
my wife drivign and me RDFing it took us about 15 minutes.
I used a Pr02004 with an adjustable RF antenuator to find the street.
Then used my Pro34, wrapped in aluminium foil to narrow it down. We
listened to the CAP for the next 4 hours until they found it. I did
call the tower and tried to expalain what I had found, but they
thought me a kook.
Maybe the SAR satellite has to accept any signal on 125.5 as valid. I
do know that older ELT did not have moudlation. But I would have
expected the FAA/FCC to require replacement by of all of the older
units by now.
Terry