GWEN Towers

Like HAARP, this is a somewhat dangerous subject, rife with kooks, cranks and wonks. But GWEN Towers are real, and worthy as a radio topic. The Ground Wave Emergency Network (GWEN) was a communications system intended for use by the U.S. government in the vent of nuclear war or other large-scale domestic military engagement. In short, GWEN was supposed to serve as a means of emergency communication for the government in the event we were attacked. GWEN stands for Ground Wave Emergency Network. More here.  Government documents describe it a bit more verbosely

"GWEN is a radio communications system designed to relay emergency messages between strategic military areas in the continental United States. The system is immune to the effects of high-altitude electromagnetic pulse (HEMP) energy surges caused by nuclear detonations in the ionosphere that would disrupt conventional communications equipment. A failure of such equipment would prevent timely communications among top military and civilian leaders and strategic Air Force locations and prevent U.S. assessment and retaliation during an attack. GWEN is an essential part of a defense modernization program to upgrade and improve our nation's communications system, thereby strengthening deterrence..."

The plan was that GWEN should be able to survive the effects of a, EMP (El;ectro-Magnetic Pulse) so that surviving leadership could retain control and direct military response via emergency messages. Early research showed that low frequency signals between 150-200 kHZ were less effected EMP. Based on that somewhat dubious idea, they pressed on. In 1978 they began testing groundwave transmissions at Kirtland Air Force Base. Eventually they would deploy a system on a sub-set of frequencies between 150-175 kHz. The network was conceived as a network of more than a hundred radio towsers based around major US cities. The final number was just 58. The network had three types of stations: Receive-only, Relay-only, and input/output stations, which presumably are send/receive.

Initially called PGCS, (Proliferated Groundwave Communications System,) The USAF put out some Program management documents around 1981, and in 1982 they changed the name to GWEN. In 1987, the Air Force Electronic Systems Division published an environmental impact study for GWEN more-or-less determining that it was harmless. Very little happened until 1992 when the USAF began actual deployment. They described sites in the following dull language:

"The facility will consist of a 299-foot-tall, low-frequency (LF) transmitter tower, three equipment shelters, an access road, and associated fences. The tower will be supported by 24 guy wires, including 12 top-loading elements. An equipment shelter at the tower base will contain an antenna tuning unit. An 8-foot-high chain link fence topped with barbed wire will surround the tower base and associated equipment shelter. A radial ground plane, composed of 60 to 100, 0.128-inch- diameter copper wires buried about 12 inches underground, will extend out about 330 feet from the tower base. A 4-foot-high fence will be installed around the perimeter of the copper radials. A second equipment area located at the site perimeter will contain two shelters housing a back-up power group (BUPG) with two internal fuel storage tanks and radio processing equipment. The BUPG will operate during power outages and for testing purposes. An LF receive antenna, consisting of a pair of 4-foot-diameter rings mounted on a 10-foot pole, and an ultrahigh-frequency (UHF) antenna, used for communicating with airborne input/output terminals and consisting of a 9-foot-high whip-like antenna mounted on a 30-foot-high pole, will also be located in this area. An 8-foot-high chain link fence topped with barbed wire will enclose the entire equipment area. A 10- foot-wide gravel road will connect this area to the tower base. A 12-foot-wide gravel road will provide access to the site from a public road."

Not very exciting right?  During deployment of the network it was found that GWEN had some interference issues. Those selected low frequencies were not vacant. GWEN ultimately did not survive.Citizens groups felt that a GWEN tower made their small town a Soviet nuclear target, then there were the cranks who believe that the government was using GWEN for mind control. As satellite systems became more viable the military lost interest. Today the network is shut down, but the USAF still operates many of these sites just leasing tower spare to offset the huge cost of the network. 

Azon Bomb

The AZON bomb was perhaps the world's first smart bomb.  AZON stood for Azimuth Only, which I'll explain. It was officially named the VB-1, the VB stood for Vertical Bomb. The whole idea of a smart bomb is that primitive explosives aren't very clever. You drop them you throw them... they detonate wherever they land when the impact, fuse or timer triggers the explosion. At some point some military minds began thinking about steering them. This is the fundamental idea behind a "smart" bomb. The  first steering mechanism of course was radio control. This was used mostly in 1944 and 1945. More here.

On this topic, I must give the hat tip to Tesla for inventing radio control in 1898. All later designs are derived from his ideas. This particular design was developed by by Major Henry J. Rand and Thomas J. O'Donnell. the word "design" there sounds like they designed a whole bomb, not so. The Azon Bomb was just a special tail fin unitbolted to a 1,000-pound GP bomb (General Purpose). While that's true, it understates what a big step this was.

With the addition of this unit, the bomb’s trajectory could be adjusted in flight via radio signals which moved the fins. But this didn't allow total control through three dimensional space. It only adjusted the yaw axis. So let's explain that. An airplane manners in 3 axis, yaw, pitch and roll. Roll is controlled by the flaps on the wings and literally could roll the airplane like a barrel. So imagine that rotation as one axis. Pitch is effectively up and down. The pilot pushes the stick forward, you dive, he pulls back you climb. It's controlled by the horizontal flaps (ailerons) on the tail. Yaw is the one you're trying to figure out. Yaw is only left/right movement controlled by the single vertical flap on the tail fin.  Here the Axon bomb is falling (a purely vertical movement) and the axon unit steers with fin adjustments. To aid steering a candela  flare was attached to the tail so a bombardier could see the bomb better for remote steering.

Four antennas wrapped around the fins and signal was tuned by a single on board radio. This was powered by a small battery with about 3 minutes of life. But three minutes was plenty. The transmitter ont eh aircraft operated at 25 watts and controlled 3 signals.  The first signal at 30-40 hertz, triggered the flare. Then two other signals controlled the flaps: one at 475 hertz for left deflection, one on 3,000 hertz for right deflection. these are extremely low frequencies.

Prior to this given good weather hitting large targets like factories was doable, but small targets like railroads, roads and bridges was difficult. But the axon could be steered onto much smaller targets.

LowFER, MedFER, HiFER, BeFERs

Every time I read a new book on radio, any arena of radio past present or future I encounter new jargon. This set of terms I found in reference to the body of regulations known as Part 15. One important section under Title 47 of the Code of Federal Regulations. These rules cover anything that emits RF deliberately or inadvertently in these regulated bands. So while these rules apply to certain broadcasters the apply equally to your laptop and cordless telephone.

LowFERs are Low-Frequency Experimental Radio and they are the strictly experimental communications in the low frequency band. Many of these broadcasters are hams, but no license is required to operate here under 1 watt of power. LowFERs experiment with longwave signals below 500kHz. The part 15 rules limit the total length of their transmission lines antenna and ground lead to 15 meters. The have a club of course http://www.lwca.org/

MedFERs are Medium-Frequency Experimental Radio (as you might have guessed) and operate between 510 and 1710 kHz. This is called the mediumwave band. Broadcasts can only operate at a power of up to 0.1 watts. There is good list of these broadcasters here.

HiFERs operate in an even higher frequency band. It's 14kHz-wide band and centered at 13.56MHz. But here power is restricted to a very weak 4.8 milliwatts.

Also related are BeFERs and 49ers. BeFERs are licensed in canada to a narrow band between the Low and Medium wave bands at about 6,700 kHz. 49ers operate at about 4,900 MHz a designation legal in both Canada and the U.S.
Popular operations in these ranges are more code, some digital broadcasts and beacons. Some even send out their own QSL cards. As low as the limits are on power, some operators have managed to send a signal over 1000 miles. Any type of modulation is permitted within the band. The most important rule is that A Part 15 operator must not cause interference to any licensed service. But in turn, they must tolerate any interference from other licensed services. If that wasn't clear enough, the man made interference is endemic to these bands. We call it QRM. There are some clips of beacons in the noise here.

Could you be illegally using a device that does not comply with part 15? Yes you could. You may never be caught, but it's not entirely uncommon. If you remember last year it came out that almost all XM and Sirius FM translators (the thingee that makes it come out your car radio) operated illegally above their allowable power. The idea that other devices have the same problem is credible.