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Old 06-21-2014, 08:24 AM   #21
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It's not possible to "triangulate" from a single position. You need two direction finders at different locations and the signal you are trying to locate at the third position. "Triangulation" (three points).

If the FCC had chosen to require all transceivers to broadcast a unique identifier and had required any purchaser of a VHF transceiver to provide his/her name and address, it would have been possible to identify anyone using a marine VHF outside of the law. They did not so it's a free for all.

It's possible to find and prosecute someone broadcasting a false "mayday" but it's not a given. Accidentally transmitting because your microphone button is stuck is not a crime.
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Old 06-21-2014, 08:31 AM   #22
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I never said triangulation was done from a single point Ron.

I thought I made it clear earlier that accidental mike keying is entirely different than issuing false mayday or vessel in need of assistance calls?

We have had 2 people in the Little Egg area charged arrested and both plead guilty for misuse of a VHF marine transmitter, transmission of false distress calls resulting in the commission of a crime.
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Old 06-21-2014, 08:43 AM   #23
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I never said triangulation was done from a single point Ron.

I thought I made it clear earlier that accidental mike keying is entirely different than issuing false mayday or vessel in need of assistance calls?

We have had 2 people in the Little Egg area charged arrested and both plead guilty for misuse of a VHF marine transmitter, transmission of false distress calls resulting in the commission of a crime.
I didn't mean to imply that you said either, I was just trying to make it clear to everyone as there seemed to be some confusion.
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Old 06-21-2014, 08:51 AM   #24
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Thanks Ron, in addition some might think Rescue 21 is a single position when in fact it might be a single operating position that uses all the towers in it's network to find a transmission. Probably better than 3 towers at times. More position data and observation of RSSI will give a better estimate of where the transmitter is located.
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Old 06-21-2014, 11:32 AM   #25
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The problem here in San Diego is the proximity to Mexico as they use VHF radio as a telephone, with no regard to frequency protocol. At times, we have to shut off the radio just to get away from the palaver.
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Old 06-21-2014, 02:40 PM   #26
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Just a few points...

While the Rescue 21 USCG radio system is a nice upgrade it's far from magc. It, or any other triangulation system is real real hit or miss system for triangulating on an open mic. First of all if there are a bunch of boats in an area...it's not accurate enough to pick out a single boat and if boats are on the move...then what? Maybe a resource will get there in time to pick the boat out of a crowd...maybe not....that's why the USCG usually doesn't dispatch for an open mike as it's not definite enough.

I'm not positive but I don't think the USCG vessels have RDF on them...at best a portable unit that unless they have improved dramatically...are difficult to use at best...and they are only on board if specifically sent out for "locate" mission.

Even if the USCG small boats did have them...it is a tedious process locating a vessel with one if you don't already have a reasonable location...and again very difficult with ore than a few boats and they are on the move.

While I'm sure there is electronic gear that can determine a "signature" of a specific piece of electronics.....it's only good for evidence and not location. It doesn't aide in locating a radio...just proving it was the one transmitting. While important maybe for "false distress" calls...I doubt it has any importance in location of a stuck mike.
I have an Apelco VHF/ADF that I took off my old boat. Finding an offender is easy as long as the mic is keyed. It points out a relative bearing to the transmitter. Turn your boat until its 000 relative and follow it. When the RB starts changing, either he is moving or you are going past. Even in a fleet, its easy to pick out the boat with a RB changing the same rate as the ADF. I have not looked at the newer CG boats up close but the older large boats used to have them. The problems I found when I actually could find a VHF/ADF were 1- They were not setup correctly and, 2- No one could figure out how it worked because of #1. The sets were ALWAYS turned OFF!!!

Here is a pic of the new Response Boat - Medium and the ADF antenna is right there on top.
http://coastguard.dodlive.mil/files/...-7518E-014.jpg
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Old 06-21-2014, 06:23 PM   #27
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I've used RDF equipment in the USCG and assistance towing business for about 35 years now...and much better stuff than the Apelco/Polaris sets.

Yes it can be easy and it can be frustrating as heck....which is my guess why the USCG doesn't go chasing down too many.

If the scenario remains frozen and there's not many vessels in the search area....OK...maybe easy... but many situations are fluid and a vessel with a keyed mike moving at a fair clip or in the ICW can be nearly impossible to locate.

Especially when there is traffic on the same channel that is stronger and keeps pulling you off your primary target.

The best scenario is when the boat is tied to a dock.
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Old 06-21-2014, 08:10 PM   #28
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That's easier said than done. Your course might take you over land or shallow areas. Also, false mayday or nuisance calls would usually last only a few seconds.
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Old 06-21-2014, 08:41 PM   #29
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Yes, false distress calls are the worst. Many resources are wasted looking for these non-existent persons in need. The new USCG equipment, Rescue 21, will help find and locate some of there perps.

In aviation, we have some cases of "phantom controllers" and pirate radio stations that interfered with air traffic control. Phantom controllers were guys issuing bogus ATC clearances on the freq. Many times, pirate radio stations transmitted at power levels fare exceeding the legal maximums. Other times, interference on the frequency was found to be an industrial site with activities like arc welding that caused interference over a wide range of freq's. I flew airplanes for the FAA specially equipped to identify, track and locate the perps. It was very gratifying to find the offender, especially in deliberate cases.

I have 18,000 hours and have flown jets all over the world and never encountered a phantom controller. I have been shot at and been illuminated by lasers, but never given bogus instructions by a phantom controller. I have been given bad instructions by real controllers...but that is a whole other subject.
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Old 06-21-2014, 08:50 PM   #30
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b. Deliberate or Intentional RFI ("Phantom Controller"). Phantom controllertype
RFI is defined as unauthorized, deliberate, or intentional transmissions by
an individual directed to aircraft or air traffic controllers,
with the intent of redirecting or giving clearance to an aircraft, or disrupting
in any way the normal flow of air traffic control duties. Due to the differences
in each situation, every deliberate RFI incident will need to be handled
individually. The following personnel/offices shall perform the duties listed
below when a phantom controller incident occurs, and these duties also clarify
the procedures described in appendix 2:

http://www.wsls.com/story/20851726/f...tom-controller

In the mid-90s, air traffic controllers at the Roanoke Regional Airport nicknamed a man "the phantom controller," according to Jim Epik, the former FAA special agent who authored a book on his experiences

Epik was one of the agents who helped arrest Eugene Bocook for impersonating an air traffic controller. Court records show Bocook spent more than a decade in federal prison for the crime.
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Old 06-21-2014, 09:58 PM   #31
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I have 18,000 hours and have flown jets all over the world and never encountered a phantom controller. I have been shot at and been illuminated by lasers, but never given bogus instructions by a phantom controller. I have been given bad instructions by real controllers...but that is a whole other subject.
They're rare, but it sometimes happens. We had a case south of Scottsdale Airport near PHX where a disgruntled resident would transmit commands to aircraft inbound from the south. He was never caught to my recollection, but we looked for him. I was there for one of the transmissions, but he then went silent.

Bad instructions from a real AT controller? Never happens, right? (JK, used to be one myself.)
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Old 06-22-2014, 10:38 AM   #32
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They're rare, but it sometimes happens. We had a case south of Scottsdale Airport near PHX where a disgruntled resident would transmit commands to aircraft inbound from the south. He was never caught to my recollection, but we looked for him. I was there for one of the transmissions, but he then went silent.



Bad instructions from a real AT controller? Never happens, right? (JK, used to be one myself.)

No doubt it must happen, I just haven't heard it. Where were you a controller?
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Old 06-22-2014, 01:47 PM   #33
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No doubt it must happen, I just haven't heard it. Where were you a controller?
San Diego, CA
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