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Author Topic:   USCG Radio Coverage Maps
jimh posted 01-22-2011 04:53 PM ET (US)   Profile for jimh   Send Email to jimh  
Due to a website re-design, the coverage maps for USCG radio installations have been moved. You can now find links to the coverage maps from

Chuck Tribolet posted 01-24-2011 08:50 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Those are the old charts, pre-DSC upgrade. Charts are not
yet avaliable for the upgrade.


jimh posted 01-24-2011 09:28 AM ET (US)     Profile for jimh  Send Email to jimh     
Chuck is probably talking about the RESCUE21 upgrade, not digital selective calling. I do not anticipate an enormous improvement in coverage in terms of distance offshore from RESCUE21 compared to existing coverage for the following reasons:

--the target of RESCUE21 seems to be direction finding improvement, not range improvement;

--the size of the new antennas used for RESCUE21 installations is much larger than the existing antennas, which are mainly omnidirectional vertical collinear arrays. The RESCUE21 antennas are rather large direction-finding arrays with eight sets of antennas. The antenna gain may not be as high as the old omni-directional antennas. The physical size is much larger. This means that tower loading will be higher. It will require much stronger towers to hold the new antennas. Whether or not the new towers will be as tall as the old remains to be seen. It looks to me that it would be difficult to install a new RESCUE21 antenna on the same tower where an old omni-directional vertical collinear array was installed because of weight and wind loading.

--the suggested range criteria is believed to be 20-nautical miles offshore, a relatively modest range of coverage

The RESCUE21 project may fill in some gaps that exist in the current coverage by adding new antenna sites.

jimh posted 01-24-2011 12:17 PM ET (US)     Profile for jimh  Send Email to jimh     
Also, as noted by the USCG on the web page linked above, the coverage maps are predictions made some time ago, and may not even reflect completely accurately the pre-RESCUE21 radio coverage. My intention in posting this notice was to give readers the new location of the directory of these links, as the previous web site and directory structure of the USCG changed, and older links to these maps may no longer work.

On a side note, RESCUE21 deployment continues in 2011, and I saw evidence of RESCUE21 radio upgrades when I visited our local small boat station in Detroit in December 2010. The Great Lakes stations were at the bottom of the list in the RESCUE21 deployment, as preference was given to ocean coastal stations.

jimh posted 01-25-2011 08:10 AM ET (US)     Profile for jimh  Send Email to jimh     
Here is a link to a map showing RESCUE21 installations. The map looks like a coverage map but it is not. The shaded circles surrounding each site are not indicators of the actual area covered.

There are a heck of a lot of installation on the Eastern side of Michigan. It looks like the field installation team is working their way North along Lake Huron's West shore.

Chuck Tribolet posted 01-25-2011 08:39 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
BTW, RESCUE 21 is operational along the entire saltwater coast
of the contiguous states, and I think Hawaii. Inland, as Jim
noted, is proceeding, Alaska yet to come.


ConB posted 08-08-2011 05:59 PM ET (US)     Profile for ConB  Send Email to ConB     
Just read this article on Looks like the northern Great Lakes will have a Rescue 21 system fully functional soon.

Coast Guard uses new technology to quickly locate flooding vessel

8/6 - Cleveland, Ohio – U.S. Coast Guard personnel in Sault Ste. Marie, Mich., used Rescue 21, new technology currently being installed in the sector's command center, to locate a sailboat taking on water with one person aboard near Drummond Island, Mich., Thursday, ending in a safe trip home for the man.

Search and Rescue controllers in the command center at Coast Guard Sector Sault Ste. Marie heard a man hail the Coast Guard on a VHF-FM marine radio at 11:48 a.m., stating his boat, the sailing vessel Tringa, was sinking, but due to other radio transmissions immediately following his call, the SAR controllers were never able to establish communication with him to ask his location.

Two radio towers picked up the distress transmission, one in Goetzville, Mich., and the other in Norwood, Mich., providing the SAR controllers with an overlapping area to direct search assets.

An aircrew in an MH-65 Dolphin rescue helicopter from Air Station Traverse City, Mich., and a boat crew in a 25-foot Response Boat from Station St. Ignace, Mich., began searching the area, continuing through the afternoon.

Rescue 21, the Coast Guard’s advanced command, control and communications system, is currently being installed in the Sector Sault Ste. Marie command center, but the project is not yet complete. But as the marine version of 9-1-1, Rescue 21 facilitates better communication and interoperability in emergency situations, and provides communications coverage out to a minimum of 20 nautical miles off the coastal zone. With its advanced direction-finding capabilities and increased range, Rescue 21 helps the Coast Guard better “hear the call,” pinpoint the location and quickly direct rescue assets to boaters in distress.

The oncoming watch of SAR controllers came in Thursday afternoon to relieve the SAR controllers who had been orchestrating the search for the sailboat since it began. Among the oncoming controllers was Chief Petty Officer John Brinkman, who completed the first class of Rescue 21 training offered to Sector Sault Ste. Marie SAR controllers just prior to coming on duty in the command center Thursday afternoon. Brinkman suggested trying to use the system to obtain a better location, despite it not yet being fully implemented.

Within five minutes of powering up Rescue 21, SAR controllers were able to obtain a precise location to redirect the helicopter and boat crew. Roughly 15 minutes later, at 5:05 p.m., the helicopter pilots radioed in to report they found the sailboat about 10 miles south of Drummond Island, Mich. It was 43 miles east of the center of the original search area, which was determined by traditional methods of triangulating position based on the positions of the radio towers that captured the call.

“Everyone in the command center got really excited when we realized how well Rescue 21 worked,” said Petty Officer 2nd Class Christopher Babcock, a SAR controller in the command center during the response. “Some of us were wondering how effective it would be, but it definitely proved it’s worth during this search.”

By communicating with the sailboat operator over the radio, the pilots learned the Madison Heights, Mich., man’s vessel stuck a submerged object, puncturing the hull. His vessel was taking on water at about five gallons per minute. The 66-year-old man said he had two dewatering pumps on board but one had stopped working. He reported the other was keeping up with the flooding. He was the only person aboard the vessel. Once the boat crew arrived on scene, a Coast Guardsman went aboard the Tringa to ensure the man’s safety and stayed aboard while the RB-S crew escorted the sailboat to Walstrom’s Marine on the Cheboygan River.

jimh posted 08-08-2011 10:30 PM ET (US)     Profile for jimh  Send Email to jimh     
ConB--That is an interesting story. However, if the old sailor had a modern DSC radio, even an RTM SC-101 radio, and had it connected to his GPS receiver, a simple push of an EMERGENCY button would have sent a broadcast message containing his precise position to the USCG and all other vessels with DSC radios in range. It is nice that the government is spending several hundred million dollars to get radio direction finding, but for my safety I would just get a modern, $150, Class-D DSC radio, and then connect the radio to my GPS receiver.

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