Chartplotter
- Thread starter All U Get
- Start date
That's pretty much it anyway.... you can sail a compass heading towards a place (as Tania set out to find Bermuda) and when you get within a 50 - 100 mile range, use the beacon to home in.... You can also triangulate from two or more known beacon sources.... or you can DR and take a number of fixes from the same beacon... just like piloting with visual nav aids.... It's way, way more work that simply looking at your boat's blip on the chart plotter screen... but hey.. what better way to exercise your brain. I actually enjoy piloting with hand bearing compass, chart and chart tools....
That jogged my foggy memory that I have a portable AM radio direction finder (in a shoreside closet) and a nice sextant (used 2 times). The older charts used to mark AM stations, but if you know a few "clear channel" AM's like 870 WWL New Orleans, you can get a good single fix. https://en.wikipedia.org/wiki/WWL_(AM)
You forgot current and drift! Ok if you are small lake sailing.
Jim...
I think it would be hard to gauge the utility of RDFs for anything other than finding the direction of "land" from your at-sea location. If I'm cruising near the CA coast, land is east to northeast, sometimes north, of me at all times unless passing between the mainland and the offshore islands, where it might also bear south. So I know where it [land] is and about where I am. I suppose if arriving from, say, Hawai'i in a week of overcast skies with no working GPS running entirely on DR, the RDF might fix the bearing of San Francisco from 40 to 50 n.mi. out by picking up an AM station there, versus, say, Monterey. Getting closer to shore where the fog starts it might even get you to near the Golden Gate if there is a second AM station you can identify and also bear from. But after that? Would two or even three reliable RDF bearings get you safely up to and through the Golden Gate in half-mile visibility? You would also have to know the location of the towers (or beacons if there are any), no? However, I suppose if radar is working you could make it in using that and charted ATONs.
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Here's an example of how RDF could be useful: We used to fish out of Shinnicock Inlet on LI's south shore. When returning to the inlet sometimes we would miss the sea buoy and you would see the beach about a mile out but didn't know if you were east or west of the inlet. All the barrier beach looks pretty much the same. You could pick a direction and run until you see something you recognized. Or, use the RDF on the Inlet beacon to determine if it was a lefty or righty. I am still trying to determine if these beacons still exist. Even my go-to ham radio guy didn't know.
This is the main reason my non-military RFD is in the closet.
Plus from my location in Gulf of Mexico, you can take almost any course and hit some land.
But since I am not in the Big Pond (Pacific Ocean), you have a point.
When I did use my mid 80's vintage RDF, I could get 3 point bearing that was within a mile of my actual position, verified by visual navigational markers.
Get out you sextants (and spear guns) when the Zombies attack and take over AM stations.
Jim...
After a quick look at the .pdf at the link below, it appears that the U.S. no longer operates RDF stations; although it does operate RAD (radar beacon) stations. Canada does, however, have many RDF stations listed for emergency use, as does the U.K. Evidently, a mariner may ask his position to be fixed via the RDFs ashore after a prepared VHF transmission from his vessel at sea. This would be independent of AIS which would not work if GPS were shut down. This activity would not have anything to do with bearing off of AM radio stations.
http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNA/Pub117bk.pdf
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Yup. Just another reason I prize some of my 25 year old charts. Of course, I have newer ones, too.
Well...if you think you might simply want to know where north America is....I guess you might have a point. That would be the Christopher Columbus school of navigating. But.... if you are trying to fix your position for a DR update, or if you are trying to determine the direction of a distress call without DSC assistance, or any other applications that might involve knowing where you are in relation to a fixed point then .... there might still be some use for the device.
I readily admit that it's way more work.... but the comment was made in response to a possible gps doomsday scenario. Even so, I'll probably not run out and buy or build one. heh, heh.
Well I spent some time following the lines that run between the plotter and input devices. I found a 12V fan behind our plotter display in the cockpit and it wasn't running when the unit was on. Without this cooling fan running it must affect the chart plotter because with everything open it ran fine for three hours at the dock. I traced the line and it got lost in the gaggle behind the nav station. When my helper gets done with the on-line shopping I was promised a few moments.
All U Get
All U Get
OK I followed the electrical lines over the weekend undoing wire bundles and cabin liner. I found that the fan behind the chart plotter wouldn't run unless two switches were both on. Never did this in five years of owning the boat. It ran for three hours last night here in Titusville, Fl with temps in the 80's. Now I just have to figure out how to get the little data boxes back on the screen.
All U Get
All U Get
Guys this is NO SMALL FEAT on board Dalmation! All-U-Get should be highly commended for this detective work!
Yep we carry a slew of GPS devices on-board too as well as a huge pack of Li AA batteries and also all of my "old school" DR tools and paper charts...Plan A - mounted MFD chartplotter (antennae 1)
Plan B - old Raymarine chartplotter at the nav station (antennae 2)
Plan C - Garmin battery powered 640 GPSmap. (built in antenna)
Plan D - Garmin GPS 76Map handheld (built in antenna)
Plan FUBAR
Garmin 3200 Series w/radar & overlay AIS at helm (plus two GPS antennas than can be switched)
Garmin 3200 Series w/radar & overlay AIS at nav station
Garmin GPSMAP 478 hand held normally at helm displaying data only
Garmin 76CSx hand held (usually used in the dinghy for gunkholing)
Magellan hand held in ditch bag (non-plotter old school lat / lon only)
iPhone 5 with iSailor, Navionics & Garmin
iPhone 6 Plus with iSailor, Navionics & Garmin
iPad Air (cellular model with built in GPS) with iSailor, Navionics & Garmin
Laptop with Open CPN
I think a lot of folks don't realize that just about any smart phone out there has a built in GPS and can be used as a GPS plotter with a myriad of navigation apps available. I use iSailor more than any other but have tried almost all of them. Any cellular enabled iPad can also do stand alone plotter duties without ever using the cellular feature because they have a built in GPS just like the phones do. While the phones and iPads have their limitations they certainly make for a great back up and most people already have them on-board. The nav apps and charts are very reasonably priced.......
I still plot position on paper if heading off shore, just in case...... Interestingly enough since 1998 we have not yet had a lost GPS signal or failure to be able to get a GPS position on-board. The only failure I have had has been a Raystar 125 antenna that was improperly designed (they forgot weep holes) and it filled with water and shorted out. Switched to a second NMEA antenna, rebooted the plotter and away we went....... Redundancy is never a bad thing on boats......
Well as if further proof is necessary, this is the response I received from the Coast Guard regarding the existence of American RDF signals. KG had posted this information in a link. I don't have any reason to doubt that link but thought I would make an inquiry anyway. Only 15 years ago! Well at least they didn't call me "Bygone."
Greetings,
Thank you for contacting the USCG Navigation Center. The last marine Radio
Direction Finder (RDF) beacon was phased out in 2000. The airport RFFs were
slated to be decommissioned in 2015. It is technology from a bygone era that
was too expensive to maintain when considering the advances offered by GPS
and radar position fixing.We hope this addresses your inquiry. In our
continuing efforts to provide high quality services to our customers, please
let us know if you found the provided answer helpful.
Sincerely,
USCG Navigation Center
Navigation Information Service
NAVCEN MS 7310
7323 Telegraph Road
Alexandria, VA 20598 - 7310
Tel: 703-313-5900
www.navcen.uscg.gov
Greetings,
Thank you for contacting the USCG Navigation Center. The last marine Radio
Direction Finder (RDF) beacon was phased out in 2000. The airport RFFs were
slated to be decommissioned in 2015. It is technology from a bygone era that
was too expensive to maintain when considering the advances offered by GPS
and radar position fixing.We hope this addresses your inquiry. In our
continuing efforts to provide high quality services to our customers, please
let us know if you found the provided answer helpful.
Sincerely,
USCG Navigation Center
Navigation Information Service
NAVCEN MS 7310
7323 Telegraph Road
Alexandria, VA 20598 - 7310
Tel: 703-313-5900
www.navcen.uscg.gov
Nice work!
Please note USCG/et.al. are shifting from one Government operation to another. Other private operations radio broadcasts (Government licensed) which includes the Amateur bands, are still beacons.
Interestingly, the only private one, is your radar, if you are with 25-50nm of a fix!
You all forgot the ZOMBIES!!Get out you sextants (and spear guns) when the Zombies attack and take over AM stations.
Jim...