To read the entire article, subscribe to
Popular Communications 



The Weirder Side Of Wireless


No Privacy For Privates

In their efforts to keep air travelers safe, Transportation Security Administration officials will be taking the gloves off—and everything else, at least electronically—for passengers at 12 airports across the country that are to install full-body scanners beginning next year.

For clearance under this new high-tech system, would-be travelers (hopefully selected at random) will step into phone booth-like “millimeter wave machines,” where beams of radio frequency energy will be projected onto their bodies. The scanners will “look” through clothing to create a highly detailed 3D silhouette of the traveler—warts and all. The resulting images, which one CNN reporter described as showing “every contour of my body, including my private parts,” will be sent electronically to viewing stations in another room, or even another city, where screeners will examine them for anything untoward.
While a blurring feature prevents the screeners from seeing a passenger’s face, not much else is left to the imagination. The images from the machine will be deleted once the traveler is cleared to fly.

Turtle Collar

An Eastern box turtle, affectionally dubbed Turtle No. 72 and equipped with a GPS tracker attached to its shell, led (literally) to the arrest of Isiah Johnson, 19, of Chevy Chase, Maryland. Johnson was charged with possession of marijuana with intent to distribute after the turtle wandered into a patch of marijuana plants growing in Washington, D.C.’s Rock Creek Park.

National Park Service researcher Ken Ferebee had been monitoring Turtle No. 72, one of three in the area being tracked by the radio transmitters, for seven years, occasionally venturing into the woods to visit her. On one of those occasions her signal led him to a stand of suspicious vegetation—about 10 four-foot-tall cannabis stalks. Ferebee contacted the police who surveilled the area, arresting the urban farmer when Johnson showed up, apparently to check on this crop, which had an estimated street value of $6,500.

Medical Alert For DWT (Driving While Texting)

The American College of Emergency Physicians issued an alert about the danger of serious accidents involving “unsafe texting practices.” Doctors cite rising reports from around the country of injuries involving text-messaging pedestrians, bicyclists, boaters, and even motorists. The dangerous behavior is, not surprisingly, especially prevalent among teenagers, and a survey conducted by AAA and Seventeen magazine found 46 percent of them admitting to driving while texting.
While some serious accidents and even deaths have been attributed to unsafe texting, most injuries involved walking into lamp posts, stop signs, or walls or tripping over curbs. One 15-year-old girl, however, fell off her horse while texting, suffering head and back injuries, and a 13-year-old girl suffered burns sustained while texting her boyfriend as she cooked noodles.

Many states have banned driving while texting and talking on cell phones without a hands-free device, but the Illinois General Assembly has taken that a step further with its HB 4520. This proposed bill would prohibit a pedestrian from using a wireless telephone while crossing a
roadway, a petty offense punishable by up to a $25 fine.

New to the lexicon: defensive walking?

To read the entire article, subscribe to
Popular Communications 



Radio’s Place In An Evolving Landscape

by Rob de Santos


Welcome to a new column about the trends affecting the communications hobby. As the name indicates, this page will focus on the horizons of communications—the cutting edge as it comes into view—and we’ll explore the latest products and ideas that are changing the world and how they may affect the readers of Pop’Comm. Sometimes we’ll review a new product, sometimes we’ll discuss the digital transformation affecting every aspect of the media, and sometimes I’ll share my musings about where we might find ourselves down the road.

By way of an introduction, I’ve been a shortwave and scanner hobbyist since 1978. These days I am an avid consumer of everything from satellite radio to the Internet. I have an Internet-based business that requires me to stay abreast of the latest technological trends. I’ve got a long professional background in technology including stints in aerospace and computers. I’m sure I’ve even met many of you already during visits to the Winter SWL Festival in Kulpsville, Pennsylvania, and other meetings over the years. And I look forward to hearing from you.

Your feedback is welcome as we take this journey. Let me know what you think and what topics you’d like to see discussed and we’ll consider those, too.

Perhaps no change in the communications world has been more dramatic than the integration of computer technology with almost every tool in our daily lives. The communications hobby has been no exception to this trend. As a consequence of the decreases in cost and increases in power brought about by new technology, radio is now undergoing wrenching changes in its distribution. While once the only way we received radio was via the “ol’ box on the bedside stand” or perhaps in our cars via analog AM and FM, things are now in tremendous flux.

Consider the options today: HD radio; satellite radio (Sirius, XM, and WorldSpace); Internet distribution (through your computer and via stand-alone Internet devices); cable (Music Choice and similar services, including selected Sirius and XM channels); portable devices (everything from the venerable Walkman to MP3 players); and cell phones (soon to be a billion dollar music market). And there’s more to come.

So what does that mean, both for radio producers and consumers? Beyond the obvious creation of more choices for consumers it probably means that we’re entering a period of “Darwinian” selection. Some content producers won’t survive, others may adapt and thrive, and some new “species” will appear on the scene. We’ve already had a bit of the latter with the profusion of thousands of Internet-based “radio stations.” Conventional AM and FM stations have put themselves out on the Internet or created podcasts to get their programs heard. HD radio is the industry and government answer to the digital transition and its success remains unclear. (We’ll be taking a more detailed look at HD radio in a future column.)

The changes also mean that the market is being divided into smaller and smaller chunks. The days when one program or station could have market shares of 25 to 50 percent in a geographic area are fading fast. This may mean leaner times for the biggest radio outlets, but it might also mean a wider market geographically.


To read the entire article, subscribe to
Popular Communications 

Digital Radio Mondiale—
The Cutting Edge Of Digital Radio

Moving Shortwave Broadcasting Into The 21st Century

by Don Rotolo, N2IRZ


As with almost everything in modern life, even our beloved shortwave broadcasts have gone digital. While you’ve probably known about digital broadcasts for years, knowing about it and listening to it are two different things. To help bridge that gap, in this article, I’ll explore the topic in detail, explain who is transmitting in digital, and how you can listen in.

Before we do that, though, let’s take a quick look at the international standard for digital shortwave (below 30 MHz) broadcast, Digital Radio Mondiale (DRM). While not exactly new—it’s been around in some form since the 1990s—there are still only a few stations that use it regularly.
DRM (not to be confused with the concept of digital rights management) is an international standard that was developed in the previous century and adopted over six years ago for worldwide use on frequencies under 30 MHz. DRM is an intelligent and flexible approach to moving shortwave broadcasting into the 21st Century, allowing for more efficient use of the broadcast spectrum while offering greatly enhanced program quality and services. More recently, action has been taken to extend the use of DRM up into higher frequencies, including FM.

The Technology In Brief

Digital audio forms the basis for digital broadcasting. I don’t want to get deeply into the technology, but it helps to know that to convert an analog audio signal into a digital data stream, one uses an Analog-to-Digital Converter (ADC). A discussion of ADCs could fill several books, so I’ll keep it simple: An ADC samples the analog signal tens of thousands (for audio) of times each second, and converts the signal voltage at the instant of sampling into a number. If we convert the “stream” of numbers back into voltages (using a Digital-to-Analog Converter, or DAC), the reproduced signal can be indistinguishable from the original. The level of fidelity depends on several factors, including the time between samples and the smallest change in voltage the ADC can discern.

The DRM standard calls for a digitally encoded signal, made up of dozens of relatively narrow radio carriers, each carrying a small part of the larger “payload” of digital data. Sophisticated software techniques are used to keep these closely spaced carriers from interfering with each other, and also prevent fading or mild interference from affecting sound quality. Different versions of the standard allow for signals that are 4.5, 5, 9, 10, 18 and 20 kHz wide.

The basic signal, which for the broadcast standard is 4.5 kHz wide, carries not only the program payload (the actual voice or music signal, sometimes mixed with data), but also information to control the receiver (which decoding scheme to use, etc.) and program content information (artist, title, upcoming programs, etc.). The information used to describe the basic signal attributes is sent on the Fast Access Channel (FAC), which is sent continuously, repeating a few times per second. This allows for a receiver to scan across the band and find DRM signals with minimal decoding delay. The Service Description Channel (SDC) tells the receiver which decoding scheme to use to start converting the data from the Main Service Channel (MSC) back into audio.

The DRM signal uses OFDM (Orthogonal Frequency Division Multiplexing) with several QAM (Quadrature Amplitude Modulated) signals to make up the signal. If these terms are new to you, think of it like this: Take a small piece of the digital data and carefully modulate it into a very narrow, but precise, AM carrier, perhaps only a few dozen Hertz wide, which carries only a small piece of the digital data “stream.” Now, pack a hundred or more of those carriers (that’s the “Frequency Division” part) next to each other into the Main Service Channel, and you can get some real data capacity. Since you know the content of each signal, you can control them so they don’t interfere with each other (that’s the “Orthogonal” part), making for a very efficient signal.


To read the entire article, subscribe to
Popular Communications 

D-STAR’s All-Digital Voice And
Data Rigs Push Technology Forward

A Current Dearth Of Equipment Doesn’t Deter Hams’ Experimentation

by Jason Togyer, KB3CNM


It combines the portability of a walkie-talkie with the reach of the Internet.

It allows hams to send data files to one another at speeds up to 128 kbps at little or no cost.

It’s a technology that’s been field-tested for almost 10 years, but which still offers plenty of room for “tinkerers.”

So why haven’t more amateurs jumped onto the D-STAR bandwagon?

D-STAR—the acronym stands for “Digital Smart Technologies for Amateur Radio”—allows hams to transmit voice and data at the same time over the same frequency. Developed in the late 1990s by Japan’s then-Ministry of Posts and Telecommunications, D-STAR was intended to create a two-way digital radio and high-speed data network for the Japanese postal service.

In 2001, the Japanese government, in cooperation with the Japan Amateur Radio League (JARL), published a set of D-STAR standards for the ham bands. By 2002, ICOM America had introduced D-STAR-equipped radios for use on 1.2 GHz (23 cm); mobile, base, and handheld rigs in the 144-MHz (2-meter) and 440-MHz (70-cm) bands debuted a few years later, while D-STAR repeaters were introduced in 2006.

With D-STAR-equipped radios and their home computers, hams can transmit data to one another in simplex mode or through a D-STAR-capable repeater. D-STAR repeaters also can be linked to one another via the 10-GHz band to create a complete wireless network independent of cell towers or the Internet. And if those repeaters are linked to Internet gateways, they can talk or send data to other hams around the world.

“Anyone who invests in D-STAR now is on the cutting edge,” says Terry Jones, W4TL, of Flowery Branch, Georgia. “It’s like when single-sideband took over from AM back in the ’50s,” says Jones, an assistant director of the SouthEastern Repeater Association (SERA). “It’s got a lot of potential.”

The Adoption Process

An all-digital mode of two-way communication that links RF with the Internet would seem to be exactly what the American Radio Relay League (ARRL) was talking about in May, when it announced at Dayton Hamvention that advancing new technologies would become the “fifth pillar” of amateur radio.

But while D-STAR enthusiasm is rising, awareness among average hams seems limited. Ask a random group of hobbyists at your Sunday-morning hamfest about D-STAR and you might get a lot of blank stares. A few hams might even get hostile, decrying the technology as “the death of ham radio” because of its incompatibility with analog FM (although all of ICOM’s D-STAR rigs also work as analog radios), or because D-STAR requires a proprietary chip. Some of the resistance is natural; after all, hams are a flinty-eyed bunch of folks, demanding that new technologies prove themselves before they plunge in. (They’re also frugal when it comes to buying new equipment. The main rig in the author’s car is a 30-year-old Clegg!) And it’s not the first technology in amateur radio that took a while to catch on; the current 2-meter band was established in 1945, but it didn’t get much usage until the late 1960s, and it didn’t really take off until the mid-1970s.

The exact number of hams currently using D-STAR isn’t easy to estimate. One clue comes from the number of repeaters currently in use. There were about 100 D-STAR repeater gateways in the United States this summer, and another dozen in Canada. By comparison, there are an estimated 8,000 conventional FM amateur repeaters in North America. Another clue comes from the number of users registered worldwide to use D-STAR Internet gateways; in August, there were about 3,700 call signs in the network. (Registration isn’t compulsory, so not all D-STAR users bother.) Considering that D-STAR rigs on 2 meters and 70 cm have been available for less than five years, the adoption rate is actually pretty good.


To read the entire article, subscribe to
Popular Communications 


Tech Showcase

Microtelecom’s Perseus:
The Next Generation Of Software-Defined Radio

by Dan Srebnick, K2DLS


Radios used to be built out of electronic parts. These parts make up the functional building blocks of a receiver. A basic receiver might contain a demodulator, an IF stage, a mixer, an RF amplifier, and an audio amplifier. The performance of receiver designs vary, based upon the individual and combined characteristics of the selected components.

To change the performance of a receiver, we can modify it by substituting a component with one of higher quality or different characteristics. For example, there have been many popular receiver upgrades over the past few years based upon replacing a stock filter with a better quality filter. One of the most popular filter upgrades of all time was the Kiwa filter upgrade for the RadioShack DX-394 general-coverage receiver. The replacement filter typically has a narrower bandwidth or better adjacent frequency rejection characteristics.

What if we could virtualize the components? The idea would be to put as little as possible of the radio function into hardware. Perhaps only pre-selection and pre-amplification need to be controlled in hardware, and we can transfer the tasks of demodulation, filtration, and amplification from hardware into software. Wouldn’t that open a whole world of new possibilities? The performance of the radio could be completely redesigned through software improvements, as opposed to hardware changes, offering extreme flexibility. For example, new methods of modulation could be decoded by adding code to existing software. An open architecture could enable the use of any third-party decoding program.

This concept is called software-defined radio (SDR). While not new, SDR is moving into its second generation. Italy’s Microtelecom, a privately held high-tech company founded in 1998 that develops and manufactures radios and telecommunication devices for special applications, has an impressive entry into the market: the Perseus SDR. The legendary Perseus was a son of Zeus and half brother of the more famous Hercules, and his radio namesake does a rather Herculean job of conquering the spectrum up to 40 MHz. I had a brief opportunity to play with the Perseus in the listening room at the last Winter SWL Festival in Kulpsville, Pennsylvania (see Pop’Comm February 2008 for more on this not-to-be-missed annual event), so I was thrilled when Stefan Brockmann of SSB-Electronic GMBH and Gerry Rodski, K3MKZ, at SSB Electronic USA, offered up an evaluation unit.

Putting It Together

In addition to the Perseus box, which is about the size of a paperback book, a computer is needed to allow the software to run. The sound card in your computer acts as the audio amplifier stage and your headphones or speakers complete the chain. It took me about five minutes to get the radio up and running. I had to install the provided USA electric plug by sliding it onto the provided modular “wall wart” assembly, connect an antenna using the provided BNC to SO-239 adapter, plug the provided USB cable into the Perseus and my computer, and install the software drivers.

My recent vintage laptop runs Vista, and when I plugged in the USB cable Vista noted that an unknown device had been plugged in and offered to install a driver. I received a warning about an unsigned driver, but with full trust in Nico’s software (Nico Palermo, IV3NWV, is the brains behind both the hardware and software of this exciting receiver), I installed the driver for the Perseus HF receiver.

The installation process for the software is simple, but it’s missing the nice touch of an automated installation package. Instead, I needed to create a subdirectory for Perseus under my Program Files directory. I then copied and pasted the radio software into that folder and manually created a desktop shortcut to the Perseus.exe executable. This process could be improved by using an automated Installshield or Wise installation package. Nico is adding features regularly to the software and the updates are available free of charge via the Perseus website at http://microtelecom.it/perseus/. But, again, the entire process still only took me minutes. The excellent user manual came on the installation CD and is also available for download from the Perseus website mentioned above.

The software for this radio requires a minimum of Windows 2000 SP4, and also runs on Windows XP SP2 or Vista. There is no Mac or Linux support at this time and it is not known if any such support is planned. The software was developed using Microsoft Visual Studio C++ and there is a developer’s kit based on Visual Studio, so the software appears to be firmly entrenched in the Windows world.


To read the entire article, subscribe to
Popular Communications 



Up Close: The ICOM IC-R2500 Communications Receiver

by Ken Reiss

ICOM introduced its first black box receiver some time ago with the IC-PCR1000, the first full-featured receiver built from the ground up as a computer-controlled device. This proved to be a popular receiver, despite the absolute need for a computer to control the unit. The PCR1000 required a 9-pin serial port, something that has unfortunately all but disappeared from the computer world, and I know many PCR1000 and Optoscan fans who still maintain older computer systems just as dedicated scanner control computers for that reason. Many third-party applications were written to take advantage of the unique features the PCR1000 offered, and it appears that its successors, the IC-R1500 and IC-R2500, will also have a wealth of software at their disposal. This month, we start an in-depth look at those latter receivers. We’ll concentrate on the IC-R2500, but most of the information applies to the IC-R1500 as well.

The versatile IC-R2500 communications receiver would be a welcome addition to any shack, but has a few surprises up its sleeve to make it even more attractive. Part of a growing family of computer-controlled receivers, two versions are offered of both models: the PCR1500 and PCR2500 are the computer-controlled-only variations; the R1500 and R2500 are the same receiver, but with the addition of a control head and a few other accessories in the package to make the system truly unique. The control head allows for remote operation of the unit, although not all functions are available. It would be an excellent system for a mobile application.

The real meat of the systems, however, is in the main unit. Both the PCR2500 and R2500 versions are full-blown communications receivers in a small box. Actually, they both offer two receivers in one—the main difference from its smaller cousin, the 1500, which does not have the sub receiver capability (see below).

The R2500 (we’ll stick with that nomenclature for the sake of ease) is quite a step up from the PCR1000, with a price tag to match. List price is just over $1,000, but the street price appears to be closer to $899. What you get for your money, however, represents a substantial upgrade from that original computer-controlled receiver.

The R2500 is truly groundbreaking and unique for a consumer receiver in a couple of ways. First, we have those two receivers we mentioned. These are referred to as main and sub, and each has an antenna jack. The sub receiver does not have quite the frequency range of the main receiver, unfortunately, as diversity reception would be quite useful on HF as well (more about that shortly). The sub receiver coverage runs from 50 to 1300 MHz (less the cellular frequencies in the United States); the main receiver can receive from 10 kHz all the way to over 3000 MHz.

Both the main and sub receivers are triple conversion and capable of all-mode reception, including AM, FM Wide, FM Narrow, SSB, and CW (SSB and CW from 0.5 to 1300 MHz only. Even at the $1000 price point, dual computer-controlled triple conversion receivers represent quite a bargain, but there’s more. Continuous tone code squelch system (CTCSS) and digital coded squelch (DCS) are both supported and easy to use in the VHF/UHF portion, which is where it’s appropriate. With an optional board, APCO-25 can also be decoded as well as the amateur radio D-STAR, with different options (for more on D-STAR, see “D-STAR’s All-digital Voice And Data Rigs Push Technology Forward” elsewhere in this issue).

With the included software, 26 banks of 100 channels each are active at any one time, but it’s a simple matter to save and load memory sets to disk for a virtually unlimited memory capability. While used with the control head, memory is limited to 1,000 channels with an additional 100 channels for scan edges. The memory channels of the control head can be loaded with the cloning mode of the software, making that a painless operation.

Dual Watch

One of the options that dual receivers offer is the ability to listen to two frequencies at a time, one on the main unit and one on the sub unit. Hams and commercial receivers have had this feature for years, and many dedicated hobbyists have simply used two or more receivers to accomplish this. Of course, in the scanner world, this became tremendously popular with the advent of trunked systems. Unfortunately, the R2500 does not have trunking capability out of the box, but it would seem ideal for some enterprising software developer to add that capability. The R2500 does, however, have dual-watch capability, so monitoring one HF channel on the main band while keeping an ear on a VHF channel on the sub band is quite easy.


To read the entire article, subscribe to
Popular Communications 


Civil Aviation Monitoring

What’s New In Aviation Communications?

by Tom Swisher, WA8PYR

There’s a new hobby afoot in Europe, and it may just be showing up over here next: monitoring Automatic Dependent Surveillance-Broadcast (ADS-B). This is a new aircraft control technology being used in Europe, and to a limited extent in the United States, that allows better tracking of aircraft for safety reasons.

ADS-B is pretty simple when it comes right down to it. Aircraft, vehicles, buildings, and other objects broadcast a periodic message giving their identification, a latitude/longitude position report, altitude, speed and any other necessary information. Other aircraft and ground stations can then receive these transmissions to provide cockpit or ground station display of surrounding traffic and other critical information.

While effective, radar is based on a signal being sent out, bouncing off the aircraft and returning to the radar station. Position is determined by the direction the antenna is pointing, while the time lag between the radar signal being sent out and then a reflection received gives the range. To get velocity information, the radar tracks the object over a period of time and gives an approximate speed.

This works reasonably well, but the problem with radar is that as the signal moves farther from the transmitter, the beam widens, making the returned signal less precise. Adding ADS-B makes the system quite a bit more accurate than standard radar, as it relies on the navigation system of the aircraft (typically GPS these days) for accurate position reports rather than the returned radar reflection.

This is a great advance for aviation safety as it will not only allow aircraft to see other aircraft in their immediate area, but will also allow controllers to better use the airspace in their area; by making highly accurate position reports available, aircraft can be spaced more closely with a high degree of safety and reliability, as well as allowing flight under conditions where it might not otherwise be feasible or safe.

ADS-B works over a variety of transmission systems, including 1090 MHz Mode-S and VHF data links. Some of the necessary equipment in some cases may already be in place in aircraft, such as cockpit displays. In addition to position reports of surrounding traffic, these displays can also show ground features, weather, obstructions such as antenna towers or buildings, airport maps, and other useful information. It can also be used on the ground for ground control radar, providing better collision avoidance and runway incursion protection, as well as controlling runway lighting, better and more accurate distress signals for search-and-rescue events, and much better control of general aviation aircraft. Since GA aircraft often don’t provide position reports when flying under visual flight rules, an automatic position report will make airspace safer by showing the positions of these aircraft.

ADS-B Heads West

Implementation of ADS-B in the United States is scheduled for an eight-year timeline starting in 2006. Between 2006 and 2009, aircraft and obstacles can be equipped voluntarily; starting in 2010, installation of ADS-B ground stations will occur throughout the United States, with completion and full use expected by 2014. Some stations are already in service, including several in the Gulf of Mexico, where the FAA has been installing ADS-B ground stations on oil and gas platforms to enhance the incomplete radar coverage of the area. The information from these stations is sent back to Houston ARTCC to allow coverage that did not exist before.
Other users in the United States include cargo carriers, which can use ADS-B to better manage their traffic flow; the University of North Dakota, which is testing ADS-B on its fleet of aircraft; and Embry-Riddle Aeronautical University, which is using ADS-B on its training aircraft for better safety.

Hearing It Here

So how do you monitor ADS-B? Well, at the moment there aren’t too many ADS-B users in the United States, but since it has been mandated in Europe since 2005 (we won’t get into the United States being behind the curve...again), you just might be able to snag messages from aircraft of European carriers. Monitor 1090 MHz to see if you catch


To read the entire article, subscribe to
Popular Communications 


The Antenna Room

CB Antenna Basics, And Revisiting HDTV Antennas

by Kent Britain, WA5VJB


Modulation and antennas certainly have some of the more interesting CB Urban Myths attached to them. For instance, you’ve no doubt heard something like “more talk power makes a mobile get out like a base station”…“cleans up your modulation,” etc. Yes, there are many interesting claims about antennas floating around, so let’s go over what’s really happening.

Antenna Length

A bigger engine generally goes faster and has more horsepower (we’ll skip over turbo charging and nitro methane for now), and a longer antenna generally works better than a shorter antenna. Despite the advertising claims, 99 percent of the time a four-foot-long antenna works better than a three-foot-long antenna. In short, you want the longest antenna that will easily fit into your garage or carport. For those of you who park outside, your limit becomes the annoying noises the antenna makes when it scrapes the underside of an overpass or the “kabong” noises as you go under trees.

Antenna Placement

For mobile use, an ideal CB antenna would be a quarterwave whip in the middle of your vehicle’s roof (see Photo). The pattern is very even in all directions with less than 1 dB of variation (Figure 1).

You also have the option of the typical trunk lid mount, with the antenna in the gap between the trunk lid and the back window. On the 11-meter band the radio waves are over 33 feet long, so the roof of the car really doesn’t block very much of the wave; in fact, the strongest signal is off the front to the car (Figure 2)—a good pattern for talking in the direction of where you’re going versus where you’ve been. A 102-inch whip, a base load, or a center load antenna would all have pretty much the same pattern.

In Figure 3 we have the pattern for the 102-inch whip, or a pretty long fiberglass whip, mounted on the back bumper. In this setup the antennas are usually mounted off to the side and you can still get in and out of the trunk. The pattern is pretty lumpy, but again you see the strongest signal in the direction of the most metal, which will generally be the case.

These patterns will hold for most cars and midsize pickup trucks. You’ll get good patterns for your F150-type pickup, but that extended cab with dullie wheels would have a few more lumps; those lumps represent only about 1/2 of an S-Unit, though, and driving around you’d never hear the difference.

The bottom line for CB: You want the longest antenna you can get in the garage!

Letters Letters, We Get Letters

From Pop’Comm reader Ed we get this comment on the last column about HDTV antennas: “But you don’t need any special antennas to get HDTV!” Well, Ed, yes and no.

In most cases your regular old TV antenna or even rabbit ears will work fine for Digital TV. Go ahead, try it; if they work, they work. But DTV has some issues that analog NTSC TV did not, and one of them is multipath. On analog NTSC a reflection off a water tower, building, mountain, etc. would show up as a “ghost” on your TV screen.
Knowing that the picture tube scans left to right in 69 µS, we can have a little fun with your “ghost”: If your TV screen is 15 inches across, then the TV signal was delayed 1/15 of 69 µS or .0000046 seconds. Radio waves, like light, travel at 182,000 miles per second (for you chaps who are about to jump all over me with a more exact number, that value is in a vacuum!), giving us .0000046 x 182000 = .39 miles. That means if your ghost is 1 inch to the right of the main picture, it’s a signal that traveled an extra .39 miles (Figure 4).

To read the entire article, subscribe to
Popular Communications 


Radio Fun

Trivia And Toons

by R.B. Sturtevant, AD7IL


Q. How are scientists able to make predictions about things like El Niño and La Niña?

A. As you’ve probably noticed we’re getting a lot more information about ocean currents and their effect on the weather and the environment. Scientists have been compiling especially good information since about 2000, when measuring devices, known as PALACE floats, were dropped into the sea at various points. The devices sink to a predetermined level and float along collecting information on water temperature, salinity, direction of drift, oxygen content, water density, and more.
After about 10 days, they pop up to the surface for an hour or so and send off a radio message to the nearest satellite. The satellite passes the information on via a download to a ground station which sends it all in for correlation. There are thousands of PALACE units out there, but since they’re only about three and a half feet long and stay submerged most of the time you’re unlikely to see any. They don’t send QSL cards, either.

Q. The Allies broke codes on the German Enigma machine, but did the Germans ever break any of the high-level codes of the British or Americans?

A. No they didn’t, because they didn’t really try. And, it may surprise you to know that nobody ever broke the Enigma codes.
First, after Dunkirk, the Germans picked up a lot of Type X British code machines. The Type X was so similar to the Enigma that the Germans could have sued the British for patent infringement if there hadn’t been a war on. Both machines were patterned after a commercially available German machine, also called Enigma, that appeared in the 1920s. The Germans realized that the machine was so complicated and could produce so many variations of a message that it was foolish to even attempt decoding (the number of possible variations produced by an Enigma machine was estimated as about the same as the number of molecules in the universe!). Therefore, they spent almost no time on the Command Level codes, opting instead to use their resources on lower level Diplomatic and Tactical codes used by lower level military commanders. The British Navy relied on Book codes, which in time were very simple for the Germans to read.

Q. What are some of the problems that can develop in radio navigation?

A. Well, assuming that the RDF (radio direction finding) equipment is working correctly in, say an airplane, there are still some things that can go wrong. For instance, if you’re a pilot working out a course that crosses a coastline at an acute angle, the radio signal can possibly be refracted. This can also happen if the signal bounces off a mountain or other terrain feature. Your homing frequency could be working another station broadcasting on or close to your desired frequency and giving you false readings. Your direction finder could turn into a “thunder storm finder” if it starts pointing in the direction of a large storm generating lightning rather than a homing beacon.

To read the entire article, subscribe to
Popular Communications 


Global Information Guide

A New Shortwave Outlet Is Borno, An Austrian Radio Threat, Mas From Mexico, And More

by Gerry L. Dexter

Nigeria has a new shortwave outlet: Borno Radio Television. It’s refurbished its domestic AM and FM outlets, providing improved service to additional Nigerian states beyond Borno. BRTV has already received a license for shortwave and plans provide service to Chad, Niger, and Cameroon. Back in earlier days Nigeria had a shortwave outlet in most of its major cities, including Borno’s capital, Maidugari (on 6100). Over time most of these fell victim to neglect and disrepair and went out of service. Perhaps by next month we’ll have some idea of the frequency and schedule. But this certainly qualifies as some rare good news!

WRNO has assumed a more or less regular schedule now on 15590 local days and 7505 evenings, the latter proving to be particularly strong.

According to log reporter Bob Fraser in Belfast, Maine, Austrian Radio is threatening to end all English language shortwave at the end of the year unless “listeners come to our aid.” I assume that means letters of support rather than financial contributions CFRX in Toronto may well be back on the air by the time you read this. Just a couple of steps need to be taken before it’s ready to go. It will be interesting to note how they do competing against CVC-Santiago, now also using 6070, and often doing quite well there.

HCJB is said to have ceased its SSB transmissions on 21455, which has been used for broadcasts to Europe in German. That unit has been turned over to experiments with DRM.

Another Mexican has shown up. Merida on 6105 is being heard by a few monitors, although poorly. It’s broadcasting the local Candela FM using the same 250-watt transmitter it used years ago. Eventually it hopes to broadcast around the clock, devoting half the time to the Mayan language. Mexico continues to offer DX challenges with difficult-to-hear outlets on 4800, 6045, (now) 6105 and 9600v.

It wasn’t just Radio Singapore International that took a dive at the end of July—it took all its other feeds down with it as well. All the various FM services, languages, and formats formerly carried on shortwave have also been trashed. I guess if you’re past a certain age you’re automatically considered out of touch and no longer worth the notice of your nearby, friendly media giant.

Reader Logs

Remember, your shortwave broadcast station logs are always welcome. But please be sure to double or triple space between the items, list each logging according to the station’s home country, and include your last name and state abbreviation after each. Also needed are spare QSLs or good copies you don’t need returned, station schedules, brochures, pennants, station photos, and anything else you think would be of interest. And, if you want to get really crazy, a photo of you at your listening post would also be welcome.

Here are this month’s logs. All times are in UTC. Double capital letters are language abbreviations (SS = Spanish, RR = Russian, AA = Arabic, etc.). If no language is mentioned, English (EE) is assumed.

ALBANIA—Radio Tirana, 13600-Shijak with Albanian folk songs at 2014. (Charlton, ON)
ARGENTINA—RAE/Radio Nacional, 11710 in EE/SS at 0115. (Linonis, PA) 0233 with EE including DX pgm. Into FF at 0330. (D’Angelo, PA) 15345 in SS at 2118. (Brossell, WI) 2305. (Charlton, ON)
ASCENSION IS.—BBC South Atlantic Relay, 15400 at 2100. (Linonis, PA) 2208. Also 17885 in FF at 1735. (MacKenzie, CA) 17850 at 1818. (Charlton, ON) 21470 at 1658. (Strawman, IA)
AUSTRALIA—(Shepparton except as indicated)—6020//9580//9590 at 1110. Also 9475//9560 at 1200 (Yohnicki, ON) 9580 at 1015 taking a beating from a Firedrake jammer on 9575. (Barton, AZ) 1055 with sports. (Charlton, ON) 9710 at 0805. (Ng, Malaysia) 13630 at 2150, 15515 at 0440, 17785 at 2306 and 17795 at 2306. (MacKenzie, CA) 15515 at 0530. (Wood, TN)
ABC Northern Territories Service, 2325, Tennant Creek, at 1152 just above the noise level. (Brossell, WI) 2485, Katherine, with talk at 1240. (Ng, Malaysia)
CVC International, 17830-Darwin in CC at 0430. (MacKenzie, CA)


To read the entire article, subscribe to
Popular Communications 


Broadcast Technology

DXpedition! The Signals Are Biting For Intrepid Broadcast Monitors

by Bruce A. Conti


Like astronomers searching the heavens for new stars, or marine biologists exploring the depths for new species, there are long-distance (DX) radio communications enthusiasts (DXers) who will go to extremes scanning the AM radio dial for exotic broadcast signals. These hardy DXers will go on a DXpedition, a radio expedition to a remote location far from the electrical noise and dial congestion of the city.

The best DXpedition locations are typically close to the ocean where the high conductivity of salt water can significantly improve reception. Not all good DX locations require an ocean view though, as we see here with our roundup of DXpedition reports and loggings, beginning in the desert southwest where distant AM radio signals were caught by surprise. All times are UTC.

Skull Valley, Arizona

“I had quite an experience camping on a ranch between Iron Springs and Skull Valley, Arizona, hearing a bunch of DX on the last day, at midday,” exclaimed Rick Barton, an avid mediumwave DXer and regular Broadcast Technology contributor. “I don’t know if it was great conditions or the location at Skull Valley, but if this is common then I may want to move there! I tuned in 640 KFI Los Angeles just before high noon. I didn’t think I should be able to get LA at noon in Arizona, but I got an absolutely clear ID on it and some other stations before it was all over.”

640 KFI Los Angeles, California, at 1901 with “KFI Traffic,” then time check, “KFI news time 12:01.”
660 KTNN Window Rock, Arizona, at 1845 with drums, Native American music, announcements and local spots in Navajo language.
680 KNBR San Francisco, California, at 1900 heard with an ID as “The Sports Leader.”
720 KDWN Las Vegas, Nevada, at 1830 with talk and promo for “The Jerry Doyle Show.”
1270 KDJI Holbrook, Arizona, at 2230 with replay of Hannity program and ID, “KVWM Show Low and KDJI Holbrook.”
1380 KLPZ Parker, Arizona, at 1930 heard with music and IDs.


Boston Area DXers club member Ross Comeau made sure he didn’t forget to pack a radio for a Bermuda family vacation earlier this year. After all, Bermuda is a location many DXers have dreamed of visiting, so Ross wasn’t about to pass up this opportunity. “It was interesting to DX from this location, about 700 miles offshore from the Carolinas, with plenty of salt water for radio signals to bounce off of, and located a lot closer to Europe, Africa, the Caribbean and South America,” reported Ross. “My DXing consisted of evenings only, as the days were filled with other activities. Once the rest of my family settled into an evening of winding down with the TV, the DX session began out on the patio. With a Radio Shack DX-399 receiver, passive loop antenna, a notebook, pen, WRTH, and enough light from the hotel room to guide me, an evening of pleasurable DX was assured.”

“In general terms, Cuban stations were plentiful, as well as numerous American stations from Boston down to Miami,” said Ross of the overall experience. He continued,

There were so many Cuban stations, especially from the Radio Rebelde network, that writing down each one would have made these loggings a Cuban special. European signals were limited, perhaps due to my relatively late evening starting times, but the 1521 Saudi Arabia powerhouse came through loud and clear. I also visited the VSB radio studios while on the island. Having verified numerous broadcast stations, including VSB, this was the first time I’d ever actually been to a distant station that I QSLed.

To read the entire article, subscribe to
Popular Communications 


RF Bits

Situational Awareness Through The Automatic Packet
Reporting System

by Dan Srebnick, K2DLS

Welcome to “RF Bits,” a new bi-monthly column on computers in the radio hobby. Before I dive into my first submission, I thought I’d introduce myself. Since I recently turned 50, I’ve been doing a whole lot of self evaluation and discovery. But one thing is for sure: I am a radio guy. I have been since I was four years old and listened to funny sounds coming out of my father’s Grundig Majestic 1088 tabletop receiver. My first television DX session occurred at age five when, early one summer morning, I noticed that Captain Kangaroo was coming in on a normally vacant channel.

If radio is somehow involved, I’ve tried it. I’ve scanned the bands from longwave to mediumwave, and shortwave to VHF and UHF. I’ve contacted the International Space Station on 2 meters and once I even made a frequency modulated lightwave contact across my driveway.

I’m also an information technology (IT) guy. I was a beta tester for AOL and thought that it would never go anywhere. I had Internet email in 1992. I have worked as a software developer—we were called programmers in those days—a network engineer, and a sysadmin. I was involved in information security well before the term identity theft slipped into common usage. So it makes sense that Pop’Comm editor Edith Lennon invited me to explore that place where radio and computing come together as one. There will be a lot of ground to cover, and I welcome your input as we move forward, but let’s take that dive in right now and look at something I recently addressed in a feature for Pop’Comm, Automatic Packet Reporting System (APRS), and how that relates to what’s known as situational awareness.

Situational Awareness And APRS

Situational awareness refers to full and accurate knowledge of the current body of conditions that need to be considered to make an operational decision. Total situational awareness is necessary to ensure a successful military or police action, air safety, utility plant operation, and traffic management. The amateur APRS protocol provides a method of taking input from many sources and mapping them onto a display that shows location of resources, sensor alarms, weather data, and allows for exchange of text messages and bulletins.

Take A Position

The most typical application that comes to mind when APRS is mentioned involves the use of a global positioning system (GPS) device as input to a mobile APRS data radio operating on 144.39 MHz. The APRS position report is a formatted data message sent at 1200 bps using a terminal node controller (TNC) and an FM-capable transceiver. The TNC includes a radio modem that generates the tones used to transmit the APRS data stream over the normal FM modulated signal.
The format of an APRS position report looks like this:

W-PHG2220 Dan in Aberdeen, NJ

Now you may not think that this string of data is too useful, but what if you could take the position and map it? The website findu.com, a database archiving weather, position, telemetry, and message info, allows you to do just that. Take a look at Figure 1. This is a mapped position report for K3GNZ (Skip), one of the active members of my local radio club. The findu.com website is made aware of a station’s position via the following method:

The station sends an APRS position report, which is received by an APRS station, called an iGate, connected to the Internet. The iGate station sends the position report on to the core APRS-IS servers. Findu.com obtains the position report via the APRS-IS servers and can plot the object and its position on a map. Findu.com will then map all position reports that it receives through the APRS iGates.

In an emergency situation, the ability to map objects and their locations becomes extremely useful. Also useful is the ability to determine which objects (or stations) are in close proximity to one another. findu.com can take an object’s location and find all other APRS objects in the general area (see Figure 2).

Another way to find out what resources are on the air in the local area is by using UI-View32 or another GUI APRS client. All of the active APRS stations and objects in the surrounding area can be viewed on a map. One possible map in UI-View32 is presented in Figure 3. This map provides situational awareness of all the APRS objects in my immediate area by showing which are active. The icon for the object reports its type, such as weather station, home station, emergency operations center, etc.

To read the entire article, subscribe to
Popular Communications 


EmComm Essentials

Emergency Communications And The Radio Hobbyist (aka YOU)

by John Kasupski, KC2HMZ

This month, I have the privilege of introducing a new bimonthly column dealing with emergency communications, or EmComm for short. This new column, which I am further privileged to have been asked to write, will deal with all the various forms of EmComm as it pertains to those of us involved in the hobby of radio. The scope of the column will run the gamut from hams involved in ARES, RACES, or other EmComm groups to REACT, the numerous Citizen Corps programs, and just plain average citizens using the available tools, including various forms of radio, to enhance their families’ security and preparedness during difficult times.

My practical experience in disaster-related operations began in January 1977, when the area I live in was hit by what history now calls The Blizzard Of ’77. Since I’ve previously mentioned it more than once in the pages of Pop’Comm, I won’t repeat the details of that event. Suffice to say that I gained some valuable EmComm experience then, and also some experience helping out at a Red Cross shelter that had been set up for victims of that storm.

Fast-forward 31 years. I’m currently a member of two EmComm teams, one of which I co-coordinate with another one of its members. I am also a trained CERT (Community Emergency Response Team) volunteer, a communications specialist with a local (county-level) implementation of the Civilian Medical Corps, and a trained SKYWARN spotter. Each of these associations in the EmComm field has resulted in various training opportunities for me. They’ve also provided the chance to participate in both exercises and actual disaster-related operations related to one incident or another that’s happened where I live. For instance, in October of 2006, in between EmComm duties, I again found myself helping out at a Red Cross shelter that had been set up for victims of a severe winter weather event.

In the 31 years since I got my first experience after that storm, I’ve learned many things, but a few points in particular will guide me in my authorship of this column.

Lessons Learned

The first of these points is that preparedness and training are the keys to successful operations to mitigate any type of incident. When the chips are down, the efforts we’ve made in order to prepare, and the training we have acquired along the way, are what gets us through. This is true whether you’re an EmComm or other volunteer or a professional first responder.

To those who have dedicated themselves to working for the good of their communities in some capacity, either as volunteers or as professionals, these two points quickly become highly evident. My next point will become evident—but it is quite difficult to achieve.

You see, the whole concept of preparedness, in your community or in mine, can be visualized as a triangle. The government agencies that are concerned with disaster mitigation constitute one of the three legs, with the private sector (businesses and non-governmental organizations that are active in disaster mitigation) constituting the second. The third leg of the triangle is the average citizen or family—the general public.

It’s easy enough to get the first two legs of the triangle established. In the first case, it’s always been considered one of the duties of governments at all levels to attempt to ensure the well being of its citizens during emergencies. I use the word “attempt” because, by definition, a disaster overwhelms the resources available for dealing with the incident. Disasters by their very nature frustrate efforts by the government to deal with them.

As for the private sector, organizations like the Red Cross, Salvation Army, and countless others have also made disaster mitigation their mission. Businesses are relatively easy to convince, because it’s quite obvious that preparedness is beneficial to the bottom line and therefore in the best financial interests of businesses to prepare for the worst.

It’s the general public that’s difficult to reach, for various reasons. For example, how do you get people living in poverty to put away food for an emergency when they’re already scrounging for their next meal? Worse yet, the public as a whole prefers to think that all those horrible events on the evening news could never happen to them. Earthquakes, hurricanes, tornadoes, floods, fires, acts of terrorism are all things that happen somewhere else, not here…until, that is, they finally do happen right here. Then, if we’ve failed to prepare for such an eventuality, we look up just in time to discover that we’ve become victims of the disaster. Not only are we in no position to help others, but we need help from others, and that in a situation where the people who need help will no doubt greatly outnumber the people who are in a position to provide assistance.

To read the entire article, subscribe to
Popular Communications 


Ham Discoveries

Sixty Meters—The Perfect Channel For A Challenge!

by Kirk Kleinschmidt, NTØZ

Scanners have channels, as do CB radios and TV sets. The English have a big channel (and a chunnel underneath it), plus the picturesque Channel Islands (as do Californians). Cable TV has the History Channel and the Weather Channel, among many others. Stereos have two—and sometimes four—channels. And certain new-agers claim to channel the energies of others.

Everyone uses channels, except in ham radio, right? Isn’t that what ham radio beginners of yesteryear sought so doggedly—the ability to leave behind crystal control (channelization) and grab onto the silky smooth freedom afforded by the knob of a variable-frequency oscillator, the VFO?

Freedom from crystals and channels was a defining privilege available to those who studied hard and passed the amateur radio tests required for admission into the select group of radio experimenters who could roam the bands at a whim. Go here. Go there. Go anywhere!

Want to know what’s going on at the upper end of 40 meters? Turn the knob and find out! Don’t like that high-pitched CW note? Carefully tweak the VFO and listen to the musical note of your choosing! CB radio jockeys, embassies, and even military ops, had channels—but we had VFOs!

Freedom Was Ours, Right? Well...Mostly.

VHF/UHF ops are still channel-bound in some ways, which is a good and useful thing. The coordination of repeater inputs and outputs, for example, serves the greater good. Even the use of calling frequencies—channels of sorts—helps hams connect on sparsely populated bands that may open and close in a flash. With an exception for a “gentlemen’s agreement” here or there, most HF hamming is VFO-controlled from band edge to band edge...except for our oddball “ham band” at 60 meters which, as you may already know, is channelized!

Getting started on our unusual and challenging five-channel ham band, from 5332 to 5405 kHz, is what this month’s column is all about.

60 Meters, Warts And All

A stroke of the FCC’s pen in mid-2003 gave U.S. amateurs secondary access to five discrete channels between 5332 and 5405 kHz—not your typical ham band, to be sure. And operating there isn’t for everyone. Sixty-meter ops have to behave well, follow substantial restrictions, both operational and “electrical,” and stay out of the way of primary users (the military and the government, mostly). That’s what secondary access means: Hams can’t interfere with comms between primary users, and we have to stop transmitting on a particular frequency when asked to by primary users.

The U.S. ham frequencies are centered on 5332, 5348, 5368, 5373, and 5405 kHz, the last of which is allocated to UK hams, who have a similar channelized allocation at 5 MHz. Discrete channels—instead of even a small ham band such as our secondary allocation at 10 MHz—were the result of a compromise between the National Telecommunications and Information Agency (NTIA), which administers spectrum occupied by government licensees, the band’s primary users, and the FCC. Essentially, the FCC was seeking a small secondary allocation near 5 MHz (at the request of hams), but the NTIA freaked out at the last second, agreeing only to the five discrete channels, which are available to General and higher-class licensees only.

Hams can transmit only USB at a maximum of 50 watts effective radiated power (ERP) and an audio bandwidth that doesn’t exceed 2.8 kHz. All transmitted energy must be centered on the prescribed channels, which makes sense in government-speak, but takes some tweaking to accommodate the way hams measure frequencies and sidebands. Let’s look at these restrictions one at a time.

To read the entire article, subscribe to
Popular Communications 


The Propagation Corner

Solar Cycle 24: Are We There Yet?

by Tomas Hood, NW7US


Everyone in the radio hobby who relies on the sun for supporting long-range communications via the shortwave radio spectrum is waiting with mixed emotions for the start of Solar Cycle 24. While the cycle “officially” started in March 2008, we’re all wondering when the sunspot activity will really start, when the steady rise of the sunspot numbers will usher in world-wide excitement on the higher HF bands.

I’ve reported before that it’s not unusual to see a prolonged period of quiet between two solar cycle periods. There’s even evidence that solar cycle minimums may occur in double “valleys,” just as the peak of a cycle may occur twice. It’s not a surprise that we’re still in the depths of a “sleeping” sunspot cycle.

There is a lot of chatter, however, that this prolonged silent period has been good for some forms of DX. The report from the lowest bands is not very encouraging, however. Many report that activity on 160 and 80 meters is disappointing, if not discouraging. Perhaps, though, we ought to see what transpires this month and through the winter. With the planetary A-Index (Ap) averaging lower this time around (as compared to the last solar cycle minimum, as illustrated in the two comparison charts of Figure 1), and with the possible slight increase in sunspot activity, could we see some more encouraging and exciting “top band” activity?
Tropical band DXing has been moderately exciting. So has AM-band (mediumwave) DXing. Again, I believe that there has been some benefit from the lower Ap numbers recorded in the last 12 months.

Looking at Figures 2 and 3, we do see that the predicted rise in Solar Cycle 24 should begin right away. This rise has been forecasted for several months now, and as each new month of real data is added to the equations used to create the forecast, there’s been very little change in this forecast. This could mean that by the time you read this, we’ll be seeing a slight increase in the number of sunspots peppering the solar disc.

Stay tuned: each month will reveal the unfolding story of the new cycle. And, please write in with any reports of your observations of DXing on any of the radio bands.

HF Propagation

Paths on 31 through 19 meters are becoming ever more reliable between North America and Europe in the mornings and between North America and Asia during the late afternoon hours. The strongest openings occur for a few hours after sunrise and during the sunset hours. Thirty-one and 25 meters will often remain open into many areas late into the night and will open early in the morning, especially when part of the propagation path moves through sunlit regions. Twenty-two and 19 may still offer nighttime paths, though these will become less reliable later in November.

Nineteen, 22, and 25 meters compete with 16 for the good daytime DX during November. They will open for DX just before sunrise and should remain open from all directions throughout the day, with a peak in the afternoon. Nighttime conditions will favor openings from the south and tropical areas. Since the Southern Hemisphere has long daylight hours, DX paths on these bands from stations in the south will be common.

The all-season bands, 31 and 25 meters, are crowded and signals are usually very strong and steady. Twenty-five meters is expected to be an excellent band for medium distance (500 to 1,500 miles) reception during the daylight hours. Longer distance reception (up to 2,000 to 3,000 miles) should be possible for an hour or two after local sunrise, and again during the late afternoon and early evening. Heavy congestion will occur here since many international and domestic broadcasters make use of 25 meters. Thirty-one meters, the backbone of worldwide shortwave broadcasting, will provide medium-distance daytime reception ranging between 400 and 1,200 miles. During November, reception up to 2,500 miles is possible during the hours of darkness, and until two to three hours after local sunrise. Thirty-one meters, too, is highly congested, making reception of weak exotic signals a bit more of a challenge.

Thirteen and 16 meters will be open during a fair number of days through November when flux levels remain above 100. Paths from Europe and the South Pacific as well as from Asia, at least during days of higher solar flux levels, are common, especially on 16 meters. Look for best conditions from Europe and the northeast before noon and from the rest of the world during the afternoon hours. Reception from the South Pacific, Australia, New Zealand, and the Far East should be possible well into the early evening. At this stage in the solar cycle, the 10.7-cm flux levels are too low to sustain band openings at these frequencies for long, if at all.



To read the entire article, subscribe to
Popular Communications 


Utility Communications Digest

Whiskey For My Men, ALE For My Radios

by John Kasupski, KC2HMZ


While those of you who listen to country music will recognize the title of this month’s column as paraphrasing the Toby Keith’s hit song “Whiskey For My Men, Beer For My Horses,” it’s really not advisable to pour beer, whiskey, or any other liquids into our radios. Fortunately, the ALE in the title doesn’t refer to beer but is, rather, an acronym for Automatic Link Establishment, a worldwide standard for HF radio communications that enables stations to make contact despite constantly changing propagation conditions and interference, with or without highly skilled radio operators behind the rig. This is accomplished through the magic of microprocessor control, but does require some knowledge for an operator to understand its use.

ALE is used worldwide by utility stations and hams. Its primary benefit is that it can automatically find the HF frequency that’s optimal for both sides of the communication link, eliminating guesswork by operators (as well as the fatigue of listening to static while monitoring on HF!) searching for the best frequencies to communicate between stations. The basic idea is to let the radio, rather than the operator, handle the “bullwork” (i.e., maintaining information on propagation conditions, what stations are on a net, and the best frequency to use to contact a station on a net).

The most commonly used (by utility stations) basic protocol standard for ALE is MIL-STD 188-141B, developed in 1999 by the U.S. Department of Defense. It’s basically a 2-kHz-wide, eight-tone MFSK (multi frequency shift keying) signal sent at a rate of 125 baud and formatted in 24-bit frames, with each frame consisting of a 3-bit preamble followed by three 7-bit long ASCII characters. Decoding at the receiving end employs DSP (digital signal processing) techniques to decode the signal at a negative signal-to-noise ratio, thus allowing the receiving station to pull the signal out even if it’s below the noise level.

While military, government, and commercial HF utility stations commonly use expensive radios that are equipped by their manufacturers to handle ALE, we hobby listeners don’t need to beg, borrow, or steal one of these pricey beauties in order to receive ALE signals. For example, if you’re a ham who has already got an HF transceiver mated to a computer that you can use to control your rig, it’s quite possible that the program PC-ALE by Charles Brain, G4GUO, already supports your radio (it supports a surprisingly lengthy list of rigs), and all you need to do to decode UTEs using ALE (as well as to operate in this mode on the ham bands) is to install and configure the program. If this doesn’t work, there are other hardware (Hoka 300-32) and software (MultiPSK, SkySweeper, WaveCom, Monteria Centurion, Multimode) options available, some commercial and some of the freeware/shareware variety.

I’ve used MultiPSK along with a Kenwood TS-450S and a Tigertronics SignaLink USB interface to effortlessly decode ALE transmissions from various networks, simply by installing the program, placing it into the proper mode, and tuning to an appropriate frequency. You can also use this setup to operate in ALE on the ham bands (in fact, there’s an excellent tutorial on setting up MultiPSK for ALE operation on MultiPSK author Patrick Lindecker, F6CTE’s website (http://f6cte.free.fr/ALE_and_ALE400_easy_ with_Multipsk.doc).

What’s The Frequency, Kenneth?

If you don’t understand the above reference, ask Dan Rather (or look him up on Wikipedia), but suffice it to say that we do need to know the appropriate frequency, or frequencies. Where to tune? An exhaustive list of known ALE networks would probably fill several pages, but here are some of the most commonly monitored networks to help you get started.

One favorite target for ALE fans is the U.S. Air Force. Its HF-Global Command System (HF-GCS) ALE Network has 16 or so ground stations communicating with various U.S. and allied assets using the following frequencies (in kHz): 3137. 4721, 5708, 6721, 9025, 11226, 13215, 15043, 18003, and 23337. There are also the USAF SIPRNET (5702, 5708, 6715, 8968, 11181, 17976, 27870) and NIPRNET (3068, 4745, 5684, 8965, 11199, 13242, 17973, 20631) networks.

To read the entire article, subscribe to
Popular Communications 


The Loose Connection

Norm’s Bus Stowaway

by Bill Price, N3AVY


I heard from Norm recently. He drove the “bus” from Maine to Florida awhile ago, back when he could do it for only (that’s only!) $1000 worth of diesel. I have a feeling he won’t be driving it to the grocery store much.

Of course, many of you might be tempted to ask if Norm had any adventures while heading down. In a word, yes. My ever-thrifty friend towed his car behind the bus for the thousand-plus mile journey, and because he had read of an RV driver who had a tire go flat or a wheel-bearing seize and catch fire on the towed vehicle, and that tire then lit a forest on fire, causing the federal government to send the errant driver a bill for some 28 zillion dollars in damages, Norm established a regimen of stopping frequently to check the towed vehicle at regular intervals. But wait—there’s more!

Norm is a consummate ham. He’s the kind of person every 2-meter operator enjoys talking with. He’s got lots of tales to tell (and a lot he wouldn’t dare tell) and with his history of working in the ham radio equipment industry, he’s got a lot of information to share.

This kept Norm chatting almost constantly during his trip along I-95, and when he wasn’t talking on 2 meters he’d catch a little music or talk radio. But the important thing with Norm was stopping to check that car he was towing. The one he couldn’t see with his mirrors. Some people might have thought he was paranoid, but he stopped every 50 miles, give or take a mile, finding himself a safe spot to pull off the road, just for a moment.

How I wish I could have been a fly on the wall of that bus when Norm was checking the wheels on the car, and the little skunk was attracted by the aroma of fresh microwave popcorn and scooted through the open door and up the stairs of the bus. Oh, be still my heart, I’d give a whole dollar to have been there when he noticed the visitor.

The way he tells it (and he’s always been pretty honest with me), he noticed the skunk smell—though not too strong—right after he got back into the bus and started it up again. After a while he realized the smell was not going away, and he wondered if he hadn’t hit a poor skunk with the back wheels of the bus. There was not much he could do about it, though, so he just kept driving. Norm was talking to a local on a repeater when his traveling companion waddled up the aisle to the front of the bus and caught his eye—well, caught his nose first—as he turned his head and saw the little fellow eating a cookie from the package by his feet.


To read the entire article, subscribe to
Popular Communications