Coast Guard RDF Capability

[Net-5]

Hi everybody,

Does anyone know what sort of RDF capability the Coast Guard has, in general? Do they have the ability to locate an RF signal source on a given VHF marine voice channel? Also, is RDF being incorporated as a feature of Rescue 21?

Thanks in advance!

[ecps92]

There is plenty to read on the CG Rescue 21 site and yup RDF is a major portion of Rescue 21

USCG: Rescue 21

Program Details - Rescue 21 System - Overview

Originally Posted by Net-5

Hi everybody,

Does anyone know what sort of RDF capability the Coast Guard has, in general? Do they have the ability to locate an RF signal source on a given VHF marine voice channel? Also, is RDF being incorporated as a feature of Rescue 21?

Thanks in advance!

[mm]

Aside from on frequency df'ing on the Helo's, I know that they also have digital selective calling (DSC) capability on marine CH70, and of course all DSC radios send GPS co-ordinates.

[Net-5]

Thanks much for the replies and the links. It will be great when Rescue 21 gets up and running nationwide! Meanwhile, I was wondering if the Coast Guard could do RDF on a voice frequency at this point? Prior to the Rescue 21 upgrade?

Lets say that a boater was transmitting a Mayday on Channel 16 but did not know their coordinates and were lost. In general, could the Coast Guard DF the vessel's VHF voice transmissions to get a fix on their location?

I know about DSC, which is a great feature. However, there are still plenty of vessels out there that don't have marine radios that are DSC capable (like mine). Just wondering if RDF was a tool the Coast Guard could use? Sounds like the helos might have that capability? Maybe in conjunction with ground stations?

I'm still a newby at the marine side of things, so any information is appreciated. Thanks!

[ecps92]

Not Really on the old systems. They could tell which Tower got the best signal, but many did not have the triangulation capability

Originally Posted by Net-5

Thanks much for the replies and the links. It will be great when Rescue 21 gets up and running nationwide! Meanwhile, I was wondering if the Coast Guard could do RDF on a voice frequency at this point? Prior to the Rescue 21 upgrade?

Lets say that a boater was transmitting a Mayday on Channel 16 but did not know their coordinates and were lost. In general, could the Coast Guard DF the vessel's VHF voice transmissions to get a fix on their location?

I know about DSC, which is a great feature. However, there are still plenty of vessels out there that don't have marine radios that are DSC capable (like mine). Just wondering if RDF was a tool the Coast Guard could use? Sounds like the helos might have that capability? Maybe in conjunction with ground stations?

I'm still a newby at the marine side of things, so any information is appreciated. Thanks!

[RKG]

Conventional DF capability (generally using Doppler Systems equipment) is not uncommon at some CG stations and aboard some CG utility vessels.

[NML-21]

Originally Posted by ecps92

Not Really on the old systems. They could tell which Tower got the best signal, but many did not have the triangulation capability

This statement is not true, Coast Guard boats and stations all have DF capability. Using a simple telephone, they could call to all of the stations and get the bearing reading from the DF and triangulate the signal. This has been done many times in the past. Plus every single station has a handheld DF device as well.