|
New to Ham Radio?
My Profile
Community
Articles
Forums
News
Reviews
Friends Remembered
Speak Out
Strays
Survey Question
Operating
Contesting
DX Cluster Spots
Propagation
Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers
Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net
|
|
1-6 of 6 messages
|
Page 1 of 1
|
|
FoxHunting to save lives?
|
Reply
|
|
by ANYHELP on November 10, 2008
|
Mail this to a friend!
|
Is it possible to do a FoxHunt on a cell phone in remote parts of Colorado assuming the cell phone was on? I’m assuming with the right equipment it’s possible, but difficult.
Do search and rescue teams ever have you guys help in this kind of search?
I ask because of the following missing friends.
http://www.9news.com/rss/article.aspx?storyid=103570
Thanks in advance.
|
| |
|
RE: FoxHunting to save lives?
|
Reply
|
|
by WB6BYU on November 11, 2008
|
Mail this to a friend!
|
Yes, it is POSSIBLE. But there are some problems due to
characteristics of the cell phone system. First, you need
to know the frequency that the cell phone will use to try
to contact the base station. That depends on which carrier
they are using, where they are, etc. If the phone is
out of coverage range it will keep trying to contact the
base at high power (as would any other cell phones in
the area.) If you could separate out which signal was
the desired one, you could try tracking it. That would
require some sort of receiver that could decode information
from the signals, however, which probably would have
to come from the cell company, unless there was only one
cell phone in the search area.
Practically, if the cell phone is on and is out of a
coverage area, it won't last long. That is because it
keeps transmitting at high power trying to connect to
the network. My guess is that most phone batteries won't
last more than 12 to 24 hours in that situation.
If you can find out from the phone provider what frequency
it would be transmitting on, and if the lost people
turned it on occasionally to check for coverage, then
you would have a chance of listening for the signal if
there were no other phones around to cause confusion.
You could also contact the phone provider to see if their
phone had contacted any of their cell sites - that might
help to narrow down the search area if it had.
I spent 10 years in Search and Rescue, and get asked
by the local Sheriff's department to help with DF projects
including ELT beacons, interference to their radio systems,
etc. Other local hams are involved in Project Lifesaver,
which uses radio tags to find patients who tend to
wander away from home.
|
| |
|
RE: FoxHunting to save lives?
|
Reply
|
|
by K0OV on November 18, 2008
|
Mail this to a friend!
|
Has the missing person's cell provider been contacted about this? About two years ago, cell signals were used to help save the family of James Kim, a Senior Editor for CNET, who perished while seeking help for them in the mountains of Oregon after a severe snowstorm.
From an article in the Winter 2007 edition of CQ-VHF Magazine:
"The very remote spot where the Kim family vehicle became snowbound was blocked from all the towers of his provider, Cingular Wireless. They could not call 911. But two clever engineers from Edge Wireless, the regional operator, scoured the call data records and found a single 'ping' from James Kim's phone at 1:30 AM to a tower near Glendale, Oregon. This brief transmission was acknowledgement of a waiting text message.
"Kim drove out of that 'sweet spot' before picking up the message, but the automatic transmission exchange was enough for the two Edge engineers to determine that his phone was less than 26 miles southwest of Wolf Peak in the little-used 'Z' coverage sector. They then employed computer models to determine areas of mountain shadowing and combined that data with their own knowledge of the region to direct searchers toward Bear Camp Road, which is where Kim's family was found in the vehicle. Kim had driven down that road by mistake because a vandal had broken a lock and opened the gate to it."
Joe
|
| |
|
RE: FoxHunting to save lives?
|
Reply
|
|
by ANYHELP on November 19, 2008
|
Mail this to a friend!
|
Thanks for the information on this; my friend was able to drive out after 7 days of hard work and prayer.
You can see the report here: http://www.wwmt.com/video/index.php?bcpid=1111405973&bclid=1137706675&bctid=1917532083
I doubt many people know their cell phone can be a type of beacon even without being able to make a call. Seems like a general cell phone frequency foxhunt in the remote parts of US would be a good way to find someone, since there wouldn’t be many, if any other phones on.
|
| |
|
RE: FoxHunting to save lives?
|
Reply
|
|
by K0OV on November 19, 2008
|
Mail this to a friend!
|
Back in the analog days, cell phones put out a continuous signal during a call, which could be monitored with an ordinary UHF receiver and tracked with an ordinary directional antenna. But now all cell phones are digital and they only put out short pulses (the di-dit, di-dit, di-dit you sometimes hear in a nearby appliance). Multiple phone signals are multiplexed on each frequency so it's impossible to tell whose phones are transmitting on a given channel with an ordinary receiver. Without some very special equipment, a searcher cannot know which of many frequencies is the right one and which of many pulse signals on each frequency is the right one to track.
To add insult to injury, the Electronic Communications Privacy Act makes it illegal for individuals to monitor and/or attempt to decode signals on cell phone frequencies.
So we have to leave it to the pros at the cell phone providers.
Joe
|
| |
|
RE: FoxHunting to save lives?
|
Reply
|
|
by KZ1X on November 23, 2008
|
Mail this to a friend!
|
it's done indoors:
http://www.radarfind.com
essentially, a thousand-plus-foxes in a computer automated foxhunt, running 24x7
|
| |
|
Email Subscription
You are not subscribed to this topic.
Subscribe!
My Subscriptions
Subscriptions Help
Check our help page for help using
Forum, or send questions, comments, or suggestions to the
Forum Manager.
|
|
|
