Driftnet Radio Buoys

A radio buoy is not a piece of hardware that the average person needs to use. In other words, you probably can't buy one refurbished on Woot. They are a type of battery powered, radio beacon used extensively used by fishing boats operating on the open sea. Popular models are made by Kato Electronics, Taiyo, Sea Star and Newstar, and Ryokuseisha Co.  More here.

By definition they are non-directional, and usually broadcast on a 4-minute loop repeating an ID three times followed by a steady carrier and a stop. They are most frequently found between 1600–2850 kHz and are very common on the 160-meter band. The ID has nothing to do with the location, it's just a unique ID to distinguish one driftnet buoy from another. They usually broadcast with a power of 4-15wats though tmuch higher strengths have been recorded. To extend battery life there is a type of radio buoy called a "SelCall buoy." These only broadcast a signal in response to one from their ship.  More here.

As you might imagine Hams  located on the coasts encounter them a lot, and other shortwave users consider them a source of RFI. They are quite difficult to manage having no fixed location, unknown power and a variable radius. VK2DX classifies them in "Endemic Groups" an elegant classification he created. [LINK] I'll just quote his explanation here:

"Due to the fact that fishnet beacons do not have a fixed location, finding the exact coverage radius could be a difficult task. The starting point into any distance or location-related analysis would be the establishment of Endemic Groups. An EG is a group of distinctive call signs (ID’s) identifiable at a particular location. In other words, EG beacons are your local beacons. For example, a study of VK2DX log reveals that the most often logged ID’s are Class 5b beacons starting with 2Axxx. The most frequent daytime loggers are 2AEGH (1807khz), 2AFYZ (1771khz) and 2ACVW (1753khz). It is therefore reasonable to conclude that 2Axxx beacons would constitute an Endemic Group based on the coast of central part of the state of NSW (VK2). Naturally, a group of beacons with different ID classes might be coexistent in the region. "

But why are they in use at all? Drift net buoys are used in situations where fishing nets aren't anchored to the boat, or another fixed anchor, like the sea floor. In other words, the nets move. They're called drift nets. They hang vertically in the water column without being anchored to the bottom. The nets are kept vertical in the water by floats attached to a rope along the top of the net and weights along the bottom of the net.There are numerous criticism of the technique [LINK] but Greenpeace had not begun jamming them yet.

First Radio Beacon in France

I can't read of speak French so you'll have to bear with me if I've missed a detail or two in this tale. 1931 was a big year for pilots in Abbeville, France.  The French Air Ministry installed a radio beacon at Abbeville. This was not a marker beacon like the modern units that transmit on 75 MHz. This was a letter beacon. While still in use today, letter beacons are not registered with the ITU (International Telecommunication Union), so even contemporary information is scarce.  But in 1931 this was such hot news that it made it into American news papers, like the New York Sun. More here.

Today some of these letter beacons are grouped in with those spooky shortwave number stations. But it's inaccurate. These have a well known origin in the early development of Air navigation technology of the 1930s. The frequency they occupy is not relevant, it does not imbue them with any mysterious purpose. They are for air navigation, and have been for almost a century now. More here. Abbeville is about eighty miles from Paris. It's population today is only about 24,000.  So you can imagine it wasn't much to look at then either. But try to understand that the first transcontinental air mail flight was only 10 years earlier. That year, 1921 the U.S. Post Office used bonfires to light the runway. A lot changed in 10 years.

This beacon in Abbeville was designed to aid travel from Dover to Paris. It consisted of two antennas  a short distance apart.  One of these sent out a constantly repeated "F" in Morse code" The other sent out a constantly repeated"L" in Morse code on the same frequency. These are similar letters but that is to it's design. A letter F in Morse code is dot dot dash dot, and L is dot dash dot dot. On pilot was quoted as saying:

"It eliminates both instrumental and human error. It is almost like following an invisible road or railway, and removes most of the uncertainty of fog flying. Where before, in thick weather, we were continually asking the control tower for positions, we now need do so only once in a complete Journey. Although both outgoing and Incoming planes use the same road, there is no danger of collision, as they fly at different heights... We fly now in weather which would formerly have held us up. The sole disadvantage is the monotony of listening to the signal."

 If the pilot hears both on the same frequency, the signals intersect to form a continuous straight line between Dover and Paris. As long as an airplane is flying along this line the pilot hears in his earphones a continuous buzzing, caused by the co mingling of the two lines of code. If he deviates form his course he will hear more clearly an L or F. At the time they were already testing a "lamp" that would flash the signal so spare pilots from the buzzing sound in their headsets, and enable them to hear other information.

Radio Fog Signals

Radio beacons cropped up very early in the development of radio. But that makes some sense. radio is a strictly non-visual medium, and so it was imagined to solve problems without a visual interface: audio communication, remote control, and navigation without visual aids. It's almost impossible to imagine what the world was thinking when it was first on the verge of these possibilities but that's my theory.

The first radio beacons testing began in 1916  courtesy of the United States Light House Service. These same units (more or less) were placed into regular service in May of 1921.  Other tests began at Navesink Lighthouse Atlantic in the New Jersey highlands but were rudely interrupted by WWI. Those tests resumed in 1919 but they were late to the party so to speak. They installed those original three experimental units at three stations. These were as follows:

1. Ambrose Channel Lightship (New York harbor)
2. Fire Island Lightship
3. Sea Girt Lighthouse.

Lightship Ambrose was a name given to numerous different lightships that served as sentinel beacons to mark the Ambrose Channel in New York Harbor.  Some even operated at the same time in different locations around the harbor. This is the Main Shipping channel on the Hudson River. The first of these lightstations was actually established south of the Ambrose Channel in 1823 just off of the coast of Sandy Hook, NJ.It was relocated in 1906 nearer to the channel. In 1967 it was replaced by a stationary platform the Texas Tower. The ship in service at the time of the radio experiments was the LV-87 also called "the Ambrose"

The Fire Island Light ship was situated about 40 miles east of the entrance to New York harbor, and about nine miles off the shore of Fire Island. It was originally stationed in 1896. But it had been borrowed from it's original duty as a lightship on Nantucket Shoals where it returned the following year. Interestingly it installed experimental Marconi wireless in 1901. The new ship that relieved it at Fire Island was the LV-68 in 1897.
It's fog signal was installed in 1906 and it's own Marconi Wireless in 1916 will the call sign NLS. It operated until 1930. More here.

The Sea Girt LightHouse marks the inlet leading to the Wreck Pond in Sea Girt, NJ south of Asbury Park. It first came into service in 1896. It was just one of the 40+ stations along the Jersey Shore. When this station was equipped with a radio beacon it was probably the first such station on shore. Because there were three stations a ship could fix its position through triangulation. In 1928, Sea Girt’s transmitter was shut down and the towers dismantled. The transmitter was transferred to Barnegat Lightship off Cape May, NJ. More here.

Radio Navigation

In several previous posts about radio navigation I've mentioned beacons, and that airplanes use them as points of reference. In one detailed post about Amelia Earhart I even roughly described the "boxing" maneuver aircraft use to orient their course.  But the particulars of this technique eluded me. Recently I found a simple 8 page student document from 1942 that comes complete with diagrams that describe four different ways to do so with a simple RDF (Radio Direction Finder) system. Later ADF (Automatic Direction Finder) systems had motorized antennas.

The first technique is called "Loop Orientation."  In using a loop antenna the loop "faces" bi-directionally. So after reaching a proper airspeed the first instruction is to set the loop indicator parallel to lateral axis of the airplane. Then the airplane is gently banked to find the first null. By holding this position, the azimuth dial can now be set. After holding that course the loop can now be rotated to find a second null. the angular difference between the 1st and second nulls determines the distance from the radio transmitter using the following formula:

Ground speed x time between nulls = distance out  / angular difference between the nulls.  For example that could be 130 mph x 3 minutes / 45 degrees. That's 8.6 miles. The use of "angular difference" is merely triangulating a location.  The document goes on to describe Radio Boxing, which further orients the path starting with the above calculations.  You can download this document at the link below

HERE

First Space Transmission

Oh there were plenty of radio signals in space before this, but none that were man made emanating from space. On October 4, 1957, the Soviet Union launched Sputnik 1, into orbit. It was the first man-made satellite. The sphere was about twice the diameter of a basketball and weighed only 183 lbs. Sputnik is the English translation of "Спутник" It just means satellite. it didnt' have much inside other than a thermometer and a battery.
Sergei P. Korolëv was the man in charge of Sputnik. He was very proud of his shining sphere once saying "“This ball will be exhibited in museums!” He was right. A model of it was hing at the Worlds fair. Of course a certain grumpy U.S. intelligent agency made them take it down.
Sputnik had two transmitters. One relayed scientific data on 40.002 Mhz. The other emitted a beep to prove that it existed. Ham radio operators across the world could hear it's beacon beeping out radio signals at 20.005 Mhz. Radio Moscow announced the frequency to encourage shortwave users to tune in. The beeps got louder and then faded with the Doppler Shift. It is often theorized that the 20.005 Mhz frequency was selected because at that point in the solar cycle, that frequency range experienced significant skip. That would ensure that more hams would easily hear the signal. The batteries lasted about 23 days at which point the beep faded and then ceased. I've made a short mix of different recordings.

President Dwight Eisenhower had already been pushing for us to get an American satillite into space. He was not very interested in the scientific data. What he wanted was the legal precedent that space was not owned by we earthlings. Previous to this property ownership was assumed to extend vertically, there was no precedent as to how far. America had also been a proponent of "continental shelf ownership" a sketchy territorial concept that squeezed shipping lanes and helped the oil industry.Anyway Dwight had already seen the photos of Russian launch facilities our U2 flights had produced. He knew it was coming. So he immediately applied pressure on the rocket programs to launch what they had. So the U.S. Army Ballistic Missile Agency duct-taped a bunch of test hardware to a wobbly Vanguard rocket. It exploded on the launch pad. The press mocked it with the nickname "Kaputnik." Only a month later Russia sent up Sputnik 2, which carried the sacrificial dog Laika into orbit. Sputink-1 burned up in orbit about 6 months later.
On Jan. 31, 1958, we did finally sent up a satellite. But it was still just the rmy Ballistic Missile Agency, not NASA that did it. Explorer 1 detected cosmic rays. It was a tad more interesting than Sputniks thermometer. NASA wasnt' formed until July 28th 1958. More here. In 1997 Russian cosmonauts launched a replica of Sputnik 1. This time from from the space station Mir, instead of terra firma. It was smaller than the original Sputnik-1, it recreated the familiar radio beacon. More here.

The First Radio Beacon

A radio beacon is non-directional transmitter that usually transmits a constant signal on a licensed radio frequency. Before the days of VOR, GPS, LORAN, beacons were used with direction finding equipment to find ones relative bearing to a known location. The beacon being the known location.

There are a few different kinds of radio beacons. There are amateur radio beacons that are used to test propagation of radio signals. At sea, there are marine beacons, though largely phased out. In aviation they use a beacon called Non-directional Beacon (NDB). These are used to help find airports.

In 1921 the first non-directional radio beacon (N.D.B.) went into service. It was operated by the Bureau of Lighthouses to assist marine navigation. A manual radio direction finder that was light enough for airborne use was developed in 1934 for these very NDBs. They were the core of navigational technology for decades.

By June 30, 1955, there were 173 NDBs operating in the United States. Since then a variety of much more dependable and accurate systems have been developed. The current plan is to decommission these beacons over the next few years as they are replaced with newer supposedly better technology. But at least today NDBs still pepper the landscape. These that still remain in service are kept as an emergency backup system in the case that these more "sophisticated" modern systems fail. Old obsolete technology is always more sturdy somehow...