I used Loran C in 1981 and my first license was a 100 ton Ocean Operator near coastal. It had a 100 mile limit and when I picked up the Loran Endorsement it was extended to 200 miles.
Decca were building the AN/SPN-31 receiver for the Navy by 1963 â tube rig, 45 kg with 52 controls. I canât find an image.
Discussion of signal at Loran-C - Signal Characteristics
it was running in Europe I thought
I visited a dive vessel with a Fuguro unit was just the same as the gps
They also had almanacs in them for the land so corrected when you signal was over the land
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Yes, the Almanacs or correction tables are essential for an accurate Loran C fix. The corrections are necessary as the propagation of the electro magnetic wave over seawater, over land an via the air are all different and are also different for each chain, the soil is never the same.
A correction factor, termed the Additional Secondary Phase Factor (ASF), reflects the fact that the Loran groundwave is further retarded when traveling over seawater as opposed to through the atmosphere. When the Loran-C signals are transmitted, part of the electromagnetic wave is in the air, and part penetrates the earthâs surface. Seawater is not as good a electrical conductor as air, so the signals are slowed as they travel over seawater.
ASFs can be found in a set of tables, called Loran-C Correction Tables, prepared and published by the Defense Mapping Agency, Hydrographic/Topographic Center (DMAHTC). These tables are published in a series of volumes, one for each loran chain. Each volume is organized into a set of pages for each station pair (master and secondary) or rate within the chain.
what I meant was that was built into the later units hence it was as good an uncorrected gps
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I remember the number 1 test of a good Loran C was how far south of Nassau you could hold a lock. Southbound the best one we had could hold on past GeorgeTown almost to Grand Turk. Going back home it wouldnât pick up until near Nassau.
The Multi-Master Loran sets were a big improvement too. No more picking chains, they used all of them all the time 
Always appreciate the confidence booster when as an AB, the captain trained/assigned me to do the Loran fixes. That rig was big as a suitcase. 1975 or so. East and Gulf coast. Some Puerto Rico work. Enjoyed it at the time just to get those little lines to line up. We hand steered and always seemed to make it to our destination. Donât miss that part, no auto pilot. Fell out of the âchairâ more than once
Had Loran A and Omega on the Coast Guard Cutters late 70âs - my memory is that Loran A was fine, little bit of work to line up the signals. Omega was awful. Not sure when we got Loran C.
Both worked well, if memory serves only major issue besides coverage in areas were angles of intercept - But my memory were both A & C were reliable.
Made a trip to Antarctica in 1980 on the USCGC Glacier - with 2 of the first Gen SAT Navâs - they were about the size of a refrigerator. And absolutely useless.
I used a Transit Satnav in the early 70âs. It was a classified piece of equipment that fitted in a standard rack. To start it up you had to load the bootstrap programme by entering the startup in binary code. The main programme loaded on a wire in a steel cassette about the size of a 8 metre steel tape.
In high latitudes the fixes were frequent. It gave you the position and information on when the satellite had been updated together with other classified information. You couldnât enter waypoints
Paper charts to translate. They made great Christmas wrapping paper later on. The few I sent gifts loved the ornamental maritime expression.
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HA - Well done
The satellites then were on a polar orbit. The higher the latitude, the more usable passes. A couple of the seismic vessels I worked on in the 70âs used doppler sonar with satellite updates. Most seismic and survey vessels in the GOM back then used Offshore Raydist, Lorac or Decca.
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None of the hyperbolic systems were available to us in the South Pacific, Southern Ocean. The Satnav did give us the predicted passes of Satellites and we could plan an operation knowing that we were going to get a fix.
As navigator on a different ship at 55 South I spent a number of days waiting for the weather to clear to get some sights so we could find and recover an instrument buoy, a job that today would be a walk in the park.
Does anyone remember the odd system where you tuned in a station and counted dots and dashes to get a bearing? I think there was one in New England someplace. Consolon??
I donât know if mariners ever used this, but aircraft had the AN system where Morse code A was one side of the line, Morse code N was the other, and a constant tone was on the line.
The name is Consol. In Europe there were base stations in Stavanger 319 kHz p, Bush Mills UK 263 kHz, LUGO Spain 303 kHz and Sevilla Spain 311 kHz. I did the counting exercise of dots and dashes a couple of times to obtain a fix approaching the British Channel in bad weather without a fix for days. I remember that we combined a Consol line with the 100 fathom line which worked rather well! We also combined it with radio bearings. You needed of course the special Consol charts to plot a fix. It was in fact a so called bombing system used by the British and American Air Force during WWII, just like GPS originally.
One of the longest lasting examples of similar systems was Sonne, which went into operation just before World War II and was used operationally under the name Consol until 1991. The modern VOR system is based on the same principles.
Consol was a long-distance locator system. The range was approximately 1000 miles by sea and 800 miles by land. The bearing error was approximately 1/6 degree, depending on conditions.
At the time, the British Ministry of Aviation had tables drawn up with which the Consol observation could be traced to a right-pointing bearing of the ship, calculated from the Consol station.
You donât need special equipment, but a radio receiver with the possibility to switch off the automatic gain control.
I started my career in the USCG in 1987. My first cutter was Tamaroa, which was a WW2 fleet tug. My first patrol was Iceberg patrol.
My ship had two Loran C receivers, which were probably old already. They were down to the size of a top loading VCR by then and were still very expensive. All they did was display a TD on an LED display, each machine was on a different line. We plotted the fix on the old Loran charts every 15 minutes. The system worked very well on the US East Coast.
If I remember correctly it was a long process to initialize the machine. You had an old menu system with a lot of scrolling and keypressing to put in the 9960 chain, the line you wanted and what hemisphere you were in.
We had a transit satellite receiver (NAVSAT) but it did not work as well as loran C. They did use it a few times in iceberg territory.
Back in those days smaller boats without a chart table and charts would actually follow a loran line to get somewhere. Some of the more expensive commercial machines could do routes and waypoints.
I see everyone is talking about the early navigation systems(electronic) such as Loran A, Loran C, Decca, Consol, anyone ever experienced Omega.
never used it but there was a one down south in Australia to support the early oil installations
this had to be the worst nav system ever to go aboard a vessel tablets upon tablets of corrections then you were never sure of the results, I used it back in the late 70s and early 80s. it was a difficult task, but thanks to some wise men/women it was quickly replaced.