February 1956 Popular Electronics
[Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
Submarines first proved their deadly
capabilities during World War II when Adolph Hitler's navy used them to torpedo not just military ships but merchant
ships in commercial trade routes between the Americas and Europe.
Hideki Tojo's navy used subs
to conduct surveillance prior to the deadly surprise attack on Pearl Harbor. Their naturally
stealthy environment - underwater - proved to be a difficult realm both for detection and for
attack. Fortunately, sensor technology developed quickly during the war, and soon a combination of
air and sea based methods were in use and proved very effective. Submariners no longer sailed in
relative security from being treated to a violent, icy burial at sea. By the mid 1950s, when this
article was published, we had detections capabilities that included direct visual, photographic,
radar, sonar, and magnetic means.
1956 must have been a big year for the General Electric plant in Utica, New York, where I had my
first engineering job right out of college, because I recently posted the
Aboard a Radar Picket Plane
article that also referenced the location.
Submarines - Are We Open to Sneak Attack?
The modern submarine, capable of submerged travel far from home
bases, and capable of delivering missiles and rockets with atomic warheads, is a fearful weapon. Newer
versions - featuring atomic power plants - appear even more formidable, and show the need for strong
defenses against their attack.
The Russian Navy, for instance, has more than twice as many submarines as the United States, and
over seven times the number of U-boats available to the Germans at the start of World War II. In this
country, however, every available means is being explored to insure an adequate and capable defense
against enemy submarines. Electronic developments, along with the planes, ships and men needed to exploit
their capabilities, are spearheading the defense.
While many of our present defense efforts are still shrouded in secrecy, some developments have been
released to the American public. The methods so far perfected emphasize the versatility of modern military
One of the best ways to seek out and destroy penetrating undersea craft is from the air. Our Navy
has many types of airplanes, helicopters and blimps especially equipped for this type of duty.
First line of defense across harbor entrance is the sono-radio buoy. Hydrophone detects
underwater sounds; these signals modulate a carrier wave which is transmitted to shore receivers. Information
received from network of buoys helps pinpoint enemy sub pack.
Carrier-based airplanes, carrying the latest in detection gear, can search out the enemy wherever
he may hide. Powerful long-range radar transmitters can sweep the surface of the seas and indicate a
tiny periscope or snorkel churning through the .waves.
Even if the enemy submarine plunges into the depths, it is not safe from the probing electronic eyes
of our fliers. Using "MAD" gear (Magnetic Airborne Detector), the surface can be searched until the
equipment receives a signal indicating the sub's hiding place. Then, sonobuoys -sensitive underwater
microphones which modulate a radio carrier - are dropped in a pattern around the area. By listening
to a receiver in the plane, any future movement of the enemy craft is immediately detected. This same
type of equipment is carried in both helicopters and blimps. Used as patrol craft, they employ their
slow speed to advantage in relentlessly hunting an enemy down for the kill. The helicopter has an additional
weapon known as the "Dipping Sonar"; this sound gear is lowered beneath the surface of the water while
the 'copter hovers motionless above it.
Panorama of coastal defense against enemy submarines involves: the strategic deployment of Navy radar
picket blimp, carrying search radar; helicopter hovering with its "Dipping Sonar" lowered into water;
a twin-engine Sentinel aircraft using MADBOOM (magnetic Airborne Detection Boom); and our own submarine
equipped with special sound apparatus. Photo insert at right shows radar units used for detection invading
ships or aircraft; scope at bottom registers targets' ranges and bearings on its screen. Across the
page, lurking in the depths, is the object of the combined search ... the enemy killer sub.
Surrounding our merchant convoys and naval task forces, destroyers equipped with special long-range
sonar equipment probe the surrounding waters for lurking under-sea craft. The type of sonar used here
"pings" impulses of sound into the water. Sensitive receivers then listen for a returning echo indicating
the presence of an enemy hull. Mast-high radar antennas continuously scan the surface for distant indications
of surfaced or snorkeling U-boats.
Information on enemy contacts is fed into the Harbor Entrance Control Post. Here,
data is evaluated, positions plotted, and orders fro action are then issued.
A glimpse behind the scenes at General Electric, Utica, N.Y., showing the
assembly of radar indicators used in our coastal defense.
Modern military warfare has even brought forth a hunter-killer submarine, especially designed to
hunt down unfriendly "cousins" that menace our shipping. Equipped with ultra-sensitive "ears," it combines
the best in listening equipment with the submarine's natural assets of stealth, cunning, and near-invisibility.
Guarding the approaches to our harbors, an entire array of unique electronic equipment awaits any
enemy who tries to penetrate our waters. Far out on the harbor approaches, sono-radio buoys keep a relentless
vigil for unexpected visitors. Like the airborne varieties, these devices combine underwater microphones
or hydrophones with radio communication. Any sound which excites the sensitive pickup modulates a radio
carrier and is noted by monitors on the shore.
The second line of defense is a series of cables laid in a pattern on the ocean floor. Called "Magnetic
Loops," they are sensitive to changes in the earth's magnetic field. Any vessel crossing the strands
immediately reveals its presence by tracing a pattern or "signature" on a pen and ink recorder on the
shore. Behind the loops are strings of hydrophones which are cable-connected to monitor stations on
the land. A constant listening watch is kept to insure the detection of even the weakest sound of a
Strategically placed along the harbor entrances are the "Heralds" (Harbor Echo Ranging and Listening
Devices). These are remotely controlled sonar transmitters and receivers that constantly ping into the
water and reveal the presence of any object by its echo. The heralds are capable of scanning the hulls
of entering vessels to make sure that nothing tries to slip in "under the skirts" of a friendly ship.
The next line of defense is an even more ingenious one. Large fields of controlled mines await any
"visitor" that gets beyond the sonar barrier. Controlled from the shore, the mines are equipped with
hydrophones and other detection devices so that they may choose the most opportune time to blow the
stranger to bits. They can be exploded by an operator listening from the shore or can be armed to fire
automatically by sound, pressure, magnetic or other devices.
All of this underwater information feeds into the HECP - Harbor Entrance Control post - along with
reports from radar operators, lookouts, and patrol craft in the harbor. From this nerve center, the
entire defense of the harbor is directed - with both air and surface craft available to take up the
battle if a penetration is attempted.
Electronics thus plays a leading role in this relentless battle to perfect our defenses. Men and
their, equipment are always ready to defend us against the submarine. This readiness may be the greatest
deterrent to another war.
Posted March 15, 2016