The Weirder Side Of Wireless
DX For The Birds (Well, Bats)
Thought it was cool DXing across the country?
How about across species? That’s what the Xtal Set Society is offering
with its new receiver kit, the ULTRA-RX1. The receiver covers the
ultrasound band of 35 to 45 kHz, allowing you to “hear” insects, rodents,
bats, and more. Signals emitted across species vary from single sine waves
to chatter with a rich mix of harmonics and pulses, according to the
Midnight Science website (www.midnightscience.com), which is offering the
kit—though you’ll generally hear a pattern of “clicks.” The emitted sound
power levels range from roughly 70 to 110 dB, sufficient to be heard from
25 to 100 feet with a high-gain receiver. Now you can thrill to the sounds
of our high-pitched friends “clicking” out their feeding, communication,
and navigational signals.
News, Trends, And Short Takes
by D. Prabakaran
ITU Agrees New Global Standard For Fully Networked Home
The first global standard offering an in-home, high-speed network capable of delivering room-to-room HDTV has been agreed by the International Telecommunication Union (ITU). The standard, published under the G.hn banner, promises high-quality multimedia over power, coaxial, phone, and other home network wiring. It will give up to 20 times the throughput of existing wireless technologies and three times that of existing wired technologies.
The specifications will be used by chip
manufacturers to build transceivers that can be incorporated into set-top
boxes, residential gateways, home computers, home audio systems, DVD
players, TVs, or any other device that might be connected to a network now
or in the future. Experts say that silicon companies will immediately
start incorporating the specifications into transceivers, implying that
G.hn-compliant products could be on the market as early as 2010.(Source:
British satellite broadcaster BSkyB has tested 3D broadcasting over the past year. Test transmissions have included top-flight boxing, English rugby, Liverpool soccer, and its popular Gladiators show. BSkyB says it has used 3D cameras at these events and successfully transmitted the signals to standard Sky+ set-top boxes.
Sky said in a statement that the trials would “help establish the potential for commercial 3D TV services.” It used a TV set from Hyundai, which requires the viewer to wear dedicated polarizing spectacles.
In addition to Sky, the BBC in the UK and Fox
in the United States have also been doing work on 3D, while Japanese
broadcasters are perhaps further advanced than any in the work being done.
A sports conference in London, reported by Rapid TV News on Dec 10, had
one expert saying they anticipated some 3D transmissions taking place in
time for the 2012 Olympic Games.
China appears to have banned a number of
foreign websites, including the BBC’s Chinese language news site and Voice
of America in Chinese, BBC News reports. The sites had been unblocked
after journalists attending the Beijing Olympics complained that the
government was censoring sites deemed sensitive. The BBC expressed
disappointment at the apparent reinstatement of the ban. But a Chinese
government spokesman told journalists that some sites contained content
that violated Chinese law. Among the other sites blocked are Asiaweek,
Reporters Without Borders, and some Hong Kong and Taiwan sites.
Capitol Hill And FCC Actions Affecting Communications
by Richard Fisher, KI6SN
Congressional Report Slams FCC Chairman Martin
Congressional investigators with the U.S.
House Energy and Commerce Committee have released a 110-page majority
staff report alleging, among other things, mismanagement, suppression of
information, and abuse of power at the Federal Communications Commission
under Kevin Martin, the commission’s Republican chairman.
Additionally, the findings allege Martin micromanaged commission affairs and demoted staffers who disagreed with him. They also charge that Martin withheld information from other FCC commissioners. The report came as the result of a yearlong, bipartisan investigation.
“Chairman Martin’s heavy-handed, opaque, and non-collegial management style has created distrust, suspicion and turmoil among the five current commissioners,” the report said.
Martin spokesman Robert Kenny said the
committee “did not find or conclude that there were any violations of
rules, laws or procedures,” according to a story by the Associated Press.
Radio logs from a fatal shooting in Baghdad in 2007 cast doubt on claims by the U.S. government that Blackwater Worldwide security guards were unprovoked when they killed 14 Iraqi civilians. Manslaughter and weapons charges have been filed against five guards for their alleged roles in the shootings. A sixth has pleaded guilty. The Blackwater radio reports, obtained by the Associated Press, document eight minutes when guards repeatedly reported incoming fire from insurgents and Iraqi police.
The men carried out a “gruesome attack on unarmed Iraqis, including women, children and people trying to escape,” prosecutors allege, as reported in the AP story. “But the radio logs from the Sept. 16, 2007 shooting suggest otherwise. Copies of the logs were turned over to prosecutors by Blackwater. Because Blackwater guards were authorized to fire in self-defense, any evidence their convoy was attacked will make it harder for the Justice Department to prove they acted unlawfully.”
The logs indicate the Blackwater convoy, named
Raven 23, reported taking small arms fire within one minute of shutting
down traffic in Baghdad’s Nisoor Square. The radio traffic was monitored
by the Blackwater dispatch center inside the Green Zone..
Software-Defined Radios On The Road?
by Rob de Santos
One trend where the radio hobby and the digital revolution have merged is in the area of the SDR, or software-defined radio. An SDR is a radio that is controlled by software, as opposed to the hardware components of the past. For example, filters, modulation circuits, amplifiers, detection devices, etc. are “created” using software loaded on a chip on a circuit board, in a personal computer, or embedded in another computing device.
Except for the physical connections to an external device (say, antennas), if it can be simulated in software, it can be done via an SDR. The big virtue of an SDR is that it can quickly be enhanced or upgraded without the need to purchase a new radio. Perhaps the SDR most readers of Pop’Comm are most familiar with would be the WinRadio models sold by WinRadio Communications.
Today’s SDRs include devices that are descendants of early research in this area by the military. The U.S. military wanted to create radios that were interoperable with other services and could be rapidly upgraded when the frequencies or technology changed. Early projects, including the “SpeakEasy,” were hampered by the speed of the central processors at the time and lack of re-configurability. The successors of those efforts are seen today in the Joint Tactical Radio System (JTRS) in wide use by the military. The backbone of the JTRS is a technology known as the open Software Communications Architecture (SCA). The SCA is now finding its way into commercial products.
In the amateur arena, hams have also been early explorers of this technology, aiding in the development of products such as the FLEX-5000, a homebrew design first described in the ARRL Handbook in 1999. Later efforts include the GNU Radio and the High-Performance Software Defined Radio (HPSDR). Like most ARRL projects, it’s all about tools and materials hams can easily access. Another feature of these projects is the use of open source software that is readily modified and free for non-commercial use.
Recent efforts in the SDR area have included
implementations of Digital Radio Mondiale (DRM) and Digital Audio
Broadcasting (DAB) receivers in software, which can then be used with
products like the WinRadio and others. SDR technology is also showing up
in other areas, such as computer-based FM and digital TV receivers.
High-Speed And Precision—
Adrenaline’s Pumping And
by Tom Swisher, WA8PYR
You, too, can monitor the SeALs. No, I’m not talking about the cute little aquatic critters. Nor am I talking about the U.S. Navy’s elite special operations unit. I’m talking about Sea (watercraft events), Air (air shows), and Land (auto racing). Each of these types of events has its own pack of aficionados, and monitoring each with your scanner can add a whole new dimension to your experience of the excitement.
Whether your tastes run to things that fly,
float, or zoom along on wheels, there’s something out there for everyone.
Do you like speed? Of course, we all do. How about boats? Sure, those are fun, too. Well, then, how about watching boats skimming across the water at over 200 mph? If that sounds cool to you, check out drag boat racing.
Drag boat racing is a match up between two boats on a measured course; whoever crosses the finish line first is the winner. Unlike land-based racing, drag boats use a slight running start, moving slowly toward the line and opening up when the light turns green. This is for safety reasons; it’s hard to judge whether the boat will move off on a straight course when starting from a dead stop due to water movement, so the slight running start is used.
Most of the races are two- or three-day events, with qualifications taking place on the first one or two days. Elimination races are held the last day of the event, with the winners of the various classes being determined that day. The classes include Top Alcohol Flatbottom (alcohol-powered boats with flat bottoms); the top boats are the Top Fuel Hydroplane class, which are hydroplanes powered by a 90/10 mixture of nitromethane and methanol. These top out at around 250 mph over a quarter-mile course.
Other racing events include regattas. These are long-distance races over a highly defined course, usually involving a group of sailboats, although there are powerboat regattas as well. The most well known regatta is the America’s Cup, although there are local regattas all over the country. Ocean-going regattas are often quite a bit more challenging than those held on inland lakes, as the course covers a much wider area.
Communications at drag boat events are used so the driver can communicate information about the performance of the boat to the crew chief, who can then recommend changes. Since the race itself is so short, most of these communications will take place before or after the race. In some classes, the crew chief even monitors such atmospheric conditions as air density, temperature, wind speed and direction, and probably even the salinity content of the water. (Remember your school science classes? A higher salt content causes objects to be more buoyant.)
ICOM IC-RX7 Wide-band Receiver
by Ed Muro, K2EPM
An attractive design, innovative frequency management features, and rugged, weather-resistant construction set the new ICOM IC-RX7 apart from run-of-the-mill conventional scanners. This is truly a scanner for the radio aficionado who’s also a race fan or air show fan.
While certain events, like NASCAR, aren’t held in rain, the benefits of the IC-RX7’s water-resistant rating will be apparent for anything that might have you scanning in inclement weather, such as Formula 1 racing or road rallies, or near sea spray during power-boat races. It would also make a perfect companion for monitoring the support action at, say, the New York City or Boston Marathon, which are often run in awful weather. It’s in such soggy venues that the IC-RX7 really hits a home run and where you’ll fully appreciate all the benefits of this feature-rich monitor radio.
According to the promotional material, the ICOM IC-RX7 is a slim and smart wideband receiver that tunes from 150 kHz to 1300 MHz (less cellular and gaps) in AM, FM Narrow, and FM wide modes. Let’s take a look at the outside first, along with some of its most obvious features; we’ll look at the software aspect of the scanner separately in an upcoming review.
The ICOM IC-RX7 offers a large back-lit LCD display plus a nice keypad. It’s rain resistant to equivalent IPX4 standard. CTCSS and DTSC decode is built in. Other features include RF Gain, Attenuator, Auto Power save and voice squelch control. A built-in ferrite rod antenna provides good medium wave (AM) reception. A total of 1,650 scannable alphanumeric memories are available, and an independent Search button automatically searches pre-programmed frequency ranges. Many sophisticated forms of scanning are supported.
As I said, it’s an attractive radio that I’d describe as a cross between a late 1990s cell phone and a TV remote control. It’s also thin and would probably fit in a shirt pocket and most definitely in a jacket or back pocket of your trousers. The slim package is made possible by a small, but high-capacity, Li-ion battery pack (BP-244), which is rated at 3.7 volts and 1100 mAh. What benefit you gain by the reduced size of the battery pack could prove a disadvantage if your battery goes dead out in the field or at a NASCAR race, but an optional AA alkaline battery case (BP-262) is available. The optional battery case would add some size to the back of the radio, but would still be a good accessory to pick up.
What appears to be a rubber gasket lines the
opening of the battery compartment, and I suspect has to do with the
splash-resistant construction equivalent to IPX4. IPX4 was a new term for
me (I’m used to the phrase “mil-spec”), so let’s look at what it refers
to. Meeting the IPX4 Standard means that the product was tested against
water splash and still functions well after being sprayed at all angles at
10 liters/min, at a pressure of 80-100kN/m2 for five minutes (though I
don’t recommend trying this at home!).
Pop’Comm Continues Its Multi-Part Acknowledgement Of The Military Branches That Serve Our Citizens
by R.B. Sturtevant, AD7IL
The Air Force, with personnel at about 329,000 strong, represents nearly a quarter of our Armed Forces, according to the Department of Defense. The men and women who serve in it have always been very technically oriented, and today the Air Force mission includes leading our defenses in air, space, and even cyberspace—the latest area vulnerable to a possible attack against the United States.
Not everything in the Air Force is about
flying, and some people spend their whole careers on the ground. But that
doesn’t mean that the Air Force is full of “chair borne” warriors, either.
For instance, Forward Ground Controllers, with their Satellite Uplink
equipment, go “where the action is.”
Hobbyists will be interested to know that ham radio played a fascinating role in the development of one aspect of Air Force communications. That goes back to the days of General Curtis E. LeMay, KØGRL/K3JUY/K4RFA, one of the founding fathers of Air Force bombing doctrine. LeMay was behind the introduction of single sideband use in Air Force aircraft. He had noticed hams at base hobby stations doing things that flight crews couldn’t and ordered research to begin on how to improve matters.
One of the tests conducted involved LeMay himself flying a bomber around the world making single sideband contacts with bases and amateurs all the way. He took other operators along, but LeMay put in his own time at the mic and key. That was back in the ‘50s and ‘60s, but the Air Force has never lost its interest in evolving technology—the newer stuff just can’t be talked about yet.
I recently talked to Staff Sergeant Jeremy
Spranger, KF9MG, about ham radio skills in today’s Air Force. Spranger has
been licensed since he was 11 years old, got his General class at 14, and
his Advanced at 16. He went into the Air Force in 1996 as an ICBM
Electronic Systems Specialist. He said that a lot of the Air Force’s 150
career fields use radio to communicate in one way or another. His amateur
radio experience helped him a great deal during his ASVAB (Armed Services
Vocational Ability Battery) testing, which all branches of the military
use to select military career fields.
Some of the technical areas in which today’s
Air Force personnel work include Communications-Electronics Systems for
Ground Radar; Ground Radio; Computer, Network, Switching and Cryptographic
Systems; and Cable and Antenna Systems. Many other technical staff put
their expertise to work as Programmers, as specialists in Communications
Computer Systems, in Operations, or Radio Communications Systems and
Electronic Spectrum Management. Professionals with radio-related skills
also staff Missile and Space Systems Maintenance, Intelligence, and
Looking For New Frequencies
by Ken Reiss
Scanner enthusiasts are always on the hunt for new frequencies to feed their scanner. When you’re just getting started, finding frequencies can be a daunting task, and you have all those channels to fill in that shiny new scanner. After a while, you’ll find what’s local and get comfortable with what you listen to on a regular basis, but there’s still a quest for other “lesser known” frequencies. That hunt for information is a part of the radio hobby, and probably always will be.
When you’re just getting started with scanning, you’re much better off with traditional published frequency lists and doing some local research. Get familiar with all that the publications and websites have to offer. See if any of your local RadioShack employees have an interest in scanning, or check to see if there’s a local website; either may offer a wealth of information that will save you a ton of work. If you can’t find local frequencies that way, have a look at RadioReference.com (www.radioreference.com) and see what it has for your area.
As you get more comfortable, you’ll start to learn the details of departments you’re monitoring as well as how they use the channels they have. You may also find additional frequencies or agencies that you didn’t think you were interested in but turn out to be quite entertaining or informative. In the process you can begin to develop a band plan for your area. As you find out what’s used and by whom, it can be very helpful to make a list of every possible channel on a band and plug in the information you already know. You’ll then see how many “holes” there are in your knowledge.
How many bands do you need to look at? Most towns of any size have something on more than one band, but there may be a pattern in your area. Some areas operate almost exclusively in the VHF range, while others (particularly large metro areas) are looking for additional channels anywhere they can be had. Don’t ignore the other bands even if your local police and fire are all in one spot. You never know what you’ll find.
Once you’ve completed your list, you can begin searching for unknowns confident that you’ll be able to correctly identify the intercepted signal, whether it’s really a new frequency for you, or just one you had forgotten about.
Even if you don’t read any of the rest of this
article (but you most definitely should!), if you actually do these
recommended approaches you’ll be way out in front of most scanner
enthusiasts and have a lot of information to share with your local club.
Take the time to catalog what you know and what you don’t know.
Ultralight DXing Goes Loopy
by Bruce A. Conti
The growing popularity of AM broadcast band DXing with ultralight radios has spurred a renewed interest in loop antenna experimentation. DXers discovered that the Sony SRF-59, Sangean DT-200VX, and Etón E100 pocket-sized radios performed better than average for modern AM radios, leading to the designation of a new category of broadcast DXer: ultralight.
Now ultralight DXers are
finding means to improve reception on these little radios, in some cases
rivaling high-end communications gear, and they’re rediscovering the magic
of the inductively coupled passive loop antenna as one way to upgrade
performance. Here’s an example, a radio electronics project sure to
delight novice and expert hobbyists alike.
During a recent meeting of the Boston Area DXers radio club, Gary Thorburn, KD1TE, demonstrated his “Spiderweb” air-core loop inductively coupled to a Sony SRF-59 ultralight AM radio. The Spiderweb Loop is an environmentally friendly design, using recycled plastic and salvaged electronic parts. As Thorburn explains,
The loop is wound with 18-gage insulated wire in a spiderweb pattern on a plastic binder cover (8.5 x 11 inches). The number of turns was experimentally determined, about 18 turns in this case. An odd number of slits in the binder results in the spiderweb pattern, with the loop woven between slits such that only nine turns are visible on each side. A notch was cut into a plastic jar, stopping about a centimeter from the jar bottom. The loop assembly is inserted in the notch.
A hole in the notebook cover of the Spiderweb Loop clears the jar cap to provide a resting place for the SRF-59, which is secured by Velcro fasteners. There is no electrical connection to the radio. The SRF-59 is positioned so its internal ferrite rod antenna is approximately centered in the Spiderweb Loop to maximize signal strength. The turns of the internal ferrite antenna and external Spiderweb Loop are in the same plane, resulting in inductive coupling. The whole assembly is easily rotated to null out undesired signals.
Thorburn suggests scavenging yard sales for old junk radios from which a tuning capacitor can be salvaged. The typical variable capacitor found in an old AM radio will adjust 10 to 365 pf. An additional fixed ceramic capacitor with a value between 80 to 200 pf is used along with a single pole single throw (SPST) switch for a high/low bandswitch. Just about anything that’s non-conductive can be used as a form for winding the loop, including sturdy cardboard, pegboard, plastic, or wood forms. Says Thorburn,
A junkbox variable capacitor is
connected across the Spiderweb Loop to tune it. A bandswitch shunts a 100
pf capacitor across the variable capacitor to cover the entire AM
broadcast band. This is often necessary in homebrew air-core loop
antennas, because the loop inherently has more capacitance and less
inductance than the typical ferrite rod antenna that a variable capacitor
is designed to tune. With the inherent capacitance of the loop already in
the equation, a larger swing in tuning capacitance is needed to cover the
entire broadcast band.
IN THE KNOW
The Worldwide Listening Guide
By John A. Figliozzi
Let’s see…we’ve finished dinner and the dishes are in the Maytag (I always stack from the back), so now, what’s on? No, no—not TV. Please! We are not going to watch Greatest Loser, or Dumber than a Second Grader, or Extreme Competitive Knitting. I mean what’s on the radio, specifically what’s on international radio? You can find the answer without having to pull your hat down over your eyes as you sneak past those frequencies filled with doctors of doom or somebody asking for a “gift” of a dollar three eighty and they’ll thank you with an autographed picture of John the Baptist. There’s a much better way: It’s a book by John Figliozzi called The Worldwide Listening Guide.
Figliozzi’s collected all the information you need to know in this regard. The book has a list of stations sorted by UTC time with program type and the frequency (or “platform,” meaning the transmission method) that runs for some 60 pages. Although the book focuses on English language programs from only a select few of the more easily accessed countries (sans United States), the listing still contains some 3,300 programs! Had Figliozzi gone “all out,” the thing would have been as thick as a major metro phone directory and the author would have had to employ half the population of Cleveland to do research. As it is, the listing provides enough listening choices to keep you busy through and beyond the next sunspot maximum.
Also included is a “Classified Program List,” a sort of cross reference to the program listing. The programs are divided into many different categories, such as Arts, Culture, and Business; Finance and Economic Development; Current Affairs, Society, Customs, Sites, People and Cultural Values; Everyday Domestic Life; Media and Communications; Ideas, Philosophy and Learning; Environmental Programs, General Documentary, General Interest, and so on. There are over 40 categories, including news, music, drama, quiz, mailbag, press review, sports, and science. Whatever your particular interest is, it’s covered.
But wait, there’s more! There’s some “how to” information, a UTC Conversion chart, websites of the stations in case you want to access streaming audio via the Internet (Figliozzi says an estimated 20,000 stations are now available on the Web). He deals with other listening options as well, such as Sirius/XM satellite services, some clear channel AM outlets and public FM stations which relay the BBC World Service, and the World Radio Network (WRN), which carries international programming from several stations.
Figliozzi provides an excellent explanation of the various means by which you can hear international programs, even recommending some receivers with which to achieve it, including the Eton E1XM, the Com One Phoenix Wi-Fi and C. Crane Wi-Fi radios.
Global Information Guide
Roars, Bhutan Is Back, And A New
by Gerry L. Dexter
Radio Romania International has finished its long tune-up process. While other European shortwave broadcasters are running for the hills, or rather, the World Wide Web, RRI plows ahead. There are now five 300 kW transmitters, three at Galbeni and two at Tiganesti. There is also a 100 kW unit employed at Saftica (how come you can never find transmitter sites in an atlas?).
Back in the December issue I reflected on Bhutan and the great difficulty involved in logging it, except for a few well-placed individuals. During the few months since, the favored zone has expanded and the Bhutan Broadcasting Service is finding welcoming ears further inland, including a few fortunates in New England and Europe.
If you feel the propagation gods are smiling, you might want to take a shot at BBS on 6035. Although it runs for a considerable length (0000 to 0700 and 0800 to 1600) most recent receptions have occurred around 1200 or 0030. But with daylight/darkness times always changing it’s almost guaranteed that those hours will no longer work. Probably we’re back to where we started and it will very likely be the spring equinox before we have a chance at Bhutan again. The BBS signal passed up most of the Midwest, certainly including Wisconsin, where yours truly finds himself.
Candela FM in Merida, Mexico, has become active on 6105, trying to make do with a mere 250 watts. Although at the beginning it was weak, somewhat distorted, and not “getting out” very well, at the moment it’s quite prominent in the evenings around 0400 and later. It’s currently scheduled from 1100 to 0500, sometimes running later. Fairly early in the morning or late evening seems to offer the best chance for hearing it. Reports for Candela FM go to Sistema RASA Yucatan, Edificio Publicentro, Calle 62 No. 508, 97000, Merida, Yucatan, Mexico. Although it’s relaying the local Candela FM now, it may very well switch to another domestic outlet sometime down the line.
Radio Vanuatu (7260) is still planning a full return to shortwave. Its regular 10 kW unit is awaiting replacement. Meantime, it’s trying to get by with a modified ham radio transmitter. Given that and the lack of logs that have come across my desk, it’s safe to say it’s not making it very far. We hope that new box arrives soon!
Also in the Pacific, the Solomon Islands
Broadcasting Corp. has reactivated its long-disused channel on 31 meters
and 9545 has returned, albeit shakily. SIBC is reportedly varying in
frequency from as high as 9550 down to about 9541. On the other hand,
5020, which had been varying down to 5019, seems to have gone silent,
although I’m guessing (hoping) that is a temporary situation.
THE PRACTICAL SIDE
The Antenna Room
More HDTV Antenna Choices
by Kent Britain, WA5VJB
It’s absolutely amazing when something really
comes together. The response to the “Cheap HDTV Antenna” in the September
2008 issue shows that it was the right project at the right time. And for
the first time, Popular Communications has made a project from the pages
of the magazine available as a website download. So if you’re still
interested in the Cheap HDTV Antenna (Photo A), but can’t find your issue
of Pop’Comm, you’ll be happy to know it’s available at
www.popular-communications.com/23-AntennasWeb92708.pdf. Our readers have
been telling me that it’s very easy to build and its performance has been
When it comes to TV antennas for HDTV reception, the FCC engineers designed the HDTV signal strengths to have the same coverage as the old analog signals. Well, they were a bit too optimistic about how sensitive the TV sets were and how fuzzy an analog picture we were willing to put up with. In short, the HDTV stations are not running enough power to get the same coverage as the good old analog stations. The TV stations would be happy to crank up the power, but the government engineers set their power levels. This means you may need to upgrade your antenna system. A nice big outside TV antenna up real high is the best TV antenna; however, many viewers will have to do the best they can with an indoor TV antenna. But the HDTV picture will be fantastic when you get enough signal for the digital circuits to start processing pictures.
In Photo B we have the classic indoor UHF TV antennas. The bowtie and UHF loops were good, yet inexpensive, indoor antennas with good reception out to 30 miles or so. Both will still work, but with a range more like 15 to 20 miles from the stations now.
About 90 percent of the HDTV transmitters will be on UHF. To make it easy on consumers, the HDTV or converter will lock up on the UHF channel, but display the old channel number. For example, locally, HDTV Channel 43 displays Channel 2 on the screen for the viewers.
In Photo C we have the next step up: log periodic UHF TV antennas. On the left is the classic of HDTV indoor devices, the “Silver Sensor”; on the right is one I’m a bit more fond of, the RDI DTV-1000—and not just because my initials are on the circuit board (hihi). The DTV-1000 has the same UHF performance as the larger “Silver Sensor,” but also has modest VHF high performance.
The log periodics give you about three to four
times as much signal as the loops or bowties and are somewhat directional.
It’s this directionality that gives you more signal and helps cut down on
reflections. Ghosting can be annoying on analog TV, and it doesn’t help on
digital all that much, either. The new “adaptive equalizers” in DTV
converters are very good at cleaning up the mixed signals cause by
reflections, but they need extra signal level to do their work properly.
So the directional antennas are a good choice especially, when most of the
TV transmitters are in somewhat the same direction.
THE INTERSECTION COMPUTERS AND RADIO
The Digital Local Broadcasting Vision
by Dan Srebnick, K2DLS
Bennett Kobb, KC5CW, is a man with a plan. He’s lobbying the FCC to allow domestic broadcasting within the United States in the 26 MHz (11 meter) broadcast band. These broadcast stations would use relatively low power, Digital Radio Mondiale (DRM) technology, and antennas specially designed to minimize skywaves. It could result in hundreds of new local and regional radio stations around the United States, provide access to the airwaves for those who are currently locked out by the high cost of buying a broadcast license, and give listeners the opportunity to hear a cornucopia of new idea—and, dare I say, talent?
Benn is truly a visionary, but the idea is
backed up with solid engineering experience. Ben’s partner in this effort
is Don Messer, with broadcast engineering experience from the likes of the
Voice of America on his resume. Benn and Don did a terrific presentation
on their plans for 26 MHz DRM broadcasting at last year’s SWL Winterfest
(see below), and I had an opportunity to speak with Benn at the Fest and
Benn met Don Messer when they both attended a meeting of the National Association of Shortwave Broadcasters. Don’s a former spectrum chief at the Voice of America, a past chair of the DRM Technical Committee, and was involved in the development of satellite broadcasters Sirius and XM. When Benn heard Don say that “the 26 MHz band is a special case, good for local broadcasting, and this could be achieved in a couple of years in the US,” he nearly fell out of his chair. You can see a copy of Don’s Winter-fest presentation on the Web at http://klixie.com/ 26mhz/files/HDM_DRM_MAR2008.PDF.
While 26 MHz is already allocated for international broadcasting as the 11 meter band, it is not currently used anywhere in the world for that purpose. Opening the band up to local broadcasting makes sense and would not require reallocation of spectrum from a non-broadcast service. Benn says that “26 MHz has VHF-like propagation characteristics” and that with use of antenna designs that attenuate skywaves, it should be quite usable for local coverage.
If you think that this idea is off the wall,
you should know that the Europeans are already experimenting with it.
There is a DRM station serving the area around Grasse, France (above
Cannes in the Maritime Alps), on 25.775 MHz in the 11 meter band (see
Figure 1). With a power of 1 kw at a height of 500 meters, the tests are
going well. If your French is better than mine, you can learn more at
http://drm cotedazur.canalblog.com. As I never studied French, I put this
page through a Web-based translator, and came up with the following, “I
took a little holiday before becoming insane and with the return I thus
have manufactured this antenna...” I wonder if Lt. Uhura did any better on
her Bluetooth, I mean, Universal Translator.
NIMS And EmComm Message Handling
by John Kasupski, KC2HMZ
While most emergency situations are handled locally, when there’s a major incident, such as the earthquake depicted in Photo A, help may be needed from other jurisdictions, maybe even the state and the federal government. In the past, this has often resulted in chaos as personnel from agencies with different radio procedures and codes struggled to communicate with each other.
To address this and other issues that arise from multijurisdictional responses, the National Incident Management System (NIMS) was developed so responders from different jurisdictions and disciplines can work together to better handle natural disasters and emergencies. NIMS teaches a unified approach to incident management, standard command and management structures, and emphasis on preparedness, mutual aid, and appropriate management of resources; in fact, the Incident Command System (ICS), perhaps the best tool out there for managing resources, is one of the backbones of NIMS.
In the aftermath of a large disaster, every entity from the Red Cross and Salvation Army to the communications groups such as ARES, RACES, and REACT (Photo B) to the Citizen Corps groups like CERT and the Medical Reserve Corps are out there to help somehow. Those of us who volunteer our time to work with various non-governmental agencies that are active in times of disaster are by no means immune to the issues that NIMS was created to help deal with. Imagine the REACT operators are using CB “10” codes, hams are using “Q” signals and prowords specified by RACES SOPs and sending messages using ARRL Radiogram format, complete with numbered ARL radiogram content, and MARS operators are using their own prowords and traffic handling procedures. In a situation like this, it’s a miracle if we can even communicate effectively with each other, let alone the dozens of local, state, and Federal personnel we may be working with.
This is precisely why NIMS calls for plain-English radio communications. In an emergency situation, when lives are at stake, time is precious. Nobody should be wasting that time on trying to determine the plain-language meaning of a transmission they just received from someone else. The phrase “medical assistance needed” along with the location where it is needed requires no reference material to explain its meaning. To send “ARL 17” or “10-38”—or anything else that has a special meaning not universally understood by English-speaking people—is not only contrary to the intent of NIMS, it is also asking for trouble. In the aftermath of a disaster, “spontaneous volunteers” come out of the woodwork wanting to do something—anything—to help. These volunteers tend to be mostly, or even completely, untrained, and may have no idea what prowords or numbered radiograms mean.
To compound the problem, the ARRL Radiogram is
not the NIMS-compliant message format. There is a NIMS general message
form: ICS-213, the accepted general message form under NIMS. It looks
nothing like an ARRL Radiogram form, but in a sense, that’s the whole
point of having it—you could yank the average schoolboy out of a high
school English class and chances are good that he would be able to
successfully write down a message on an ICS-213 form. Many, and these days
maybe even most, hams would be hard-pressed to fill out an ARRL Radiogram
form correctly. This is no problem if the correct message form under NIMS
(ICS-213) is being used.
Portable Operating: The Cure For The Urban Ham Blues
As a teenage DXer with a modest, small-town station, accommodating parents, and a lot of radio gumption, getting on the air from my basement shack (where else?) was always a thrill. Unlike the present doldrums, sunspots were very cooperative in the late ’70s and early ’80s, and there was DX aplenty—even on the Novice bands—with stations wall to wall on several (most) bands at once.
On a Saturday morning I’d chat with Scandinavians on 10 meters...hams in the rest of the world (or stateside) on 20 and 15 meters for the bulk of the day...and at supper time I’d practice my Japanese by talking with JA hams on 10 meters. Twenty and 40 meters were jam-packed but, alas, 30 meters wasn’t yet a ham band!
Each passing day brought something new, but propagation was sure and steady (now I’d kill for conditions half that good!). I’d “clunk-clunk” down the wooden stairs into my basement room/shack, flip the switch on my trusty Tempo One transceiver (built by Yaesu and a lot like an FT-101) and diligently scour the bands for interesting signals.
What’s that? No juicy DX? No problem. I could swish over to 75-meter SSB and check into Minnesota’s Piconet All Day Watch to chat with the friendly Old-Timers from around the state. Out in the boonies, Piconet was the closest thing I had to a 2-meter repeater! Some ops were strong, sounding like broadcast stations, while some were weaker. Everyone, however, was copyable, because there was no noise!
Universities aside, there were no computers
around spewing RF into the ether (and no packet spotting systems, either),
no broadband over power line issues (no broadband, period!), no Nintendo
game systems, no cranky neighbors and no deed restrictions, hence, no need
for hidden or indoor antennas. If a power pole had a noisy insulator or
RF-buzzing transformer, a ham-friendly lineman would inherently understand
the situation and would often fix it the same day. The utility companies
didn’t retain RFI specialists and PR agencies because they just weren’t
In our condo, one of 24 side-by-side units, my YL and I have five PCs, sometimes more (I do some PC tech work). To save precious electricity we switched to inexpensive compact fluorescent light bulbs throughout the house, and so did everyone else in a 100-mile radius. My antenna, a 40-meter horizontal loop that runs around the inside perimeter of the third-story attic (my unit and my through-the-wall neighbor’s, with permission), is fed through an automatic antenna coupler that’s also in the attic.
Performance-wise, the attic loop kicks butt, and I often don’t even notice that I’m using a “compromise antenna.” The big problem, however, is the loop’s proximity to all of that “garbage RF” coming from dozens of PCs, light bulbs, doorbell transformers, furnace motors, bi-metallic thermostats, dimmer switches, street lights, etc., from the entire “modern” neighborhood.
THE PRACTICAL SIDE
Gordon West’s Radio Ways
Tune In High-Frequency Marine And Aero Weather
by Gordon West, WB6NOA
For casual cruising sailors as well as
long-range commercial shipping, voice weather reports over high frequency
are extremely important. They can also make for exciting high-frequency
single sideband listening. If you have a portable or fixed HF receiver
capable of tuning SSB, there’s plenty of weather information on upper
You can get started right away by checking out
these US Coast Guard frequencies:
Listen on the hour and the half hour for the
synthesized voice of one or several US Coast Guard official weather
broadcasts. The USCG transmits National Weather Service (NWS) forecasts
and warnings, using multi-kilowatt HF transmitters, transmitting on
frequencies between 3 and 30 MHz, located at 7 USCG Communications Centers
in the following locations:
These powerful broadcasts are easily picked up
with a modest long wire antenna system. Be sure to have a chart or map
with latitude and longitude coordinates; these official broadcasts cover
large ocean areas, and you’ll need some sort of reference when they give
the latitude and longitude boundaries.
Synthesized voice weather reports are also
broadcast from commercial high seas station WLO in Mobile, Alabama, and
KLB, Washington State. Again, keep your marine charts handy, as weather
reports are given over large geographic areas, listed only as latitude and
THE PRACTICAL SIDE
The Propagation Corner
The Sun Often “Tears Out A Wall” In Earth’s Magnetic Shield
by Tomas Hood
In past columns, we’ve explored the basic mechanics of the Earth’s magnetosphere’s interaction with solar wind and the plasma that rides the magnetic field lines spiraling out away from the sun. The model used defined the magnetosphere as a type of shield around the Earth that deflected most of the solar wind and that kept solar plasma from entering our atmosphere. The model also defined how the solar wind and solar particles (ions and electrons) could enter our atmosphere if certain conditions occurred. It was believed that when the sun’s magnetic field lines were aligned with those of the Earth, the magnetosphere deflected most of this solar plasma. On the other hand, when the orientations were reversed, a “reconnection” occurred that allowed the plasma to “rain” down along Earth’s magnetic field lines, ending up at our planet’s north and south magnetic poles.
Scientists were surprised when NASA’s THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission blew away this long-standing belief. “Twenty times more solar particles cross the Earth’s leaky magnetic shield when the sun’s magnetic field is aligned with that of the Earth compared to when the two magnetic fields are oppositely directed,” says Marit Oieroset of the University of California, Berkeley, lead author of one of two papers on research of THEMIS data, published May 2008 in Geophysical Research Letters.
Solar and geophysical researchers have suspected a mechanism that allowed solar particles to enter through the magnetosphere during periods when the sun and Earth were magnetically aligned. However, they never realized how important this mechanism might actually be. “It’s as if people knew there was a crack in a levy, but they did not know how much flooding it caused,” says Oieroset.
Before THEMIS, a number of research spacecraft could only sample a small part of this enormous layer of solar particles inside the Earth’s magnetic shield. Now, because there are five spacecraft in the THEMIS fleet, scientists could use these spacecraft to span the entire rapidly growing layer to give definitive measurements.
While the THEMIS researchers discovered the size of the leak, they didn’t know where these leaks might exist. This was discovered by Wenhui Li of the University of New Hampshire, Durham, New Hampshire, and his team. They used a computer simulation to discover where two holes frequently develop in Earth’s magnetic field, one at high latitude over the Northern hemisphere, and one at high latitude over the Southern hemisphere. The holes form over the daylit side of Earth, on the side of the magnetic shield facing the sun (see image).
The scientists created a simulation that modeled just how these leaks develop. The model is actually pretty simple. As has been explained in past issues, the old model was correct in the physics involved when the two fields point in the same direction, at equatorial latitudes. However, Li’s team realized that the solar magnetic field drapes against Earth’s field as it passes by and that they point in opposite directions at high latitudes. When compression forces the opposite fields together, they link up with each other in a process called magnetic reconnection. This process tears the two holes in Earth’s magnetic field and appends the section of the solar field between the two holes to Earth’s field, carrying the solar particles on this section into the magnetosphere, according to Li’s team. “We’ve found if the door is closed, the sun tears down a wall. The crack is huge—about four times wider than Earth and more than seven Earth diameters long,” said Li.
THE PRACTICAL SIDE
The Wireless Connection
Restoring The Indicating Traceometer
by Peter J. Bertini
Let’s delve into the restoration the Hickok model 155 Indicating Traceometer featured in our last column. It may seem odd to devote a column to the restoration of a rare, eclectic piece of test equipment, but there are enough similarities between the Hickok and those made by other competing manufacturers to make the endeavor worthwhile. Also, restoration is restoration, and many of the tips and techniques are equally applicable to other vacuum tube-based vintage equipment.
The restoration will be covered in a two-part article because of the number of supporting photos and diagrams required and because of the relatively complexity of the project due to the instrument’s numerous service functions.
If you’re going to be restoring a Hickok
Traceometer, I suggest having schematics for both the 155 and 156 models
on hand. My 155 incorporated many circuit changes that were documented in
the manual for 156; having both schematics cleared up the confusion
whenever small circuit changes didn’t follow the model 155’s schematic; in
those cases the changes were depicted in the model 156 schematic. You can
download, without cost, either manual from http://bama.sbc.edu/hickok.htm.
I always begin by doing a quick check of all of the resistor values. I do so with the resistor in circuit since, at worst, parallel paths would only lower the resistance readings. In most cases carbon composition resistors tend to increase in value as they age. If a resistor shows a lower value, a quick glance at the schematic usually gives a clue about whether further investigation is needed. The resistors in the Hickok 155 were about the worst I’ve encountered, with values that ranged from three to four times higher than marked! (Photo A shows a bottom view of the unrestored chassis.)
Ditto for the wax paper capacitors. After years of restoring I’ve learned that it’s hardly worth the effort to test wax paper capacitors…if they aren’t leaky now, they will become so, requiring repairs down the line or causing equipment damage. Whew! Photo B is a graphic example of what I’m taking about. The red pen tip is pointing towards what’s left of a 1500 Ohm dropping resistor that supplied B+ voltages to a stage in the IF-RF tuned RF voltmeter band-switched coil assembly. This mess was caused by a bypass capacitor that shorted. Two 1500 Ohm resistors suffered the same fate because of shorted bypass capacitors.
While restoring the Hickok chassis seemed
deceptively easy, the pile of replaced components shown in Photo C gives
some idea of the amount of labor entailed in this restoration.
Utility Communications Digest
Grand Forks AFB To Add HF-GCS Duties
by John Kasupski, KC2HMZ
The question before us this month is: Who will be the first to log the new Grand Forks HF-GCS station when it becomes operational this year?
Utility listeners with any amount of experience are undoubtedly at least aware of the High Frequency Global Communications System (HF-GCS), a network of HF communications stations which supports a variety of U.S. and allied military commands as well as elements of the National Command Authority (specifically, the White House Communications Agency and the Joint Chiefs of Staff). HF-GCS is a highly automated communications system linking USAF command and control aircraft to other airborne and ground-based command nodes via HF radio.
The HF-GCS is currently operated by communications technicians at Andrews Air Force Base, Maryland, just outside of Washington, D.C., but “Utility Communications Digest” has now learned that the USAF’s Air Mobility Command has selected Grand Forks AFB in North Dakota to serve as the system’s alternate control station, expected to become operational in that capacity this year.
To prepare for this mission, the base, home of the 319th Refueling Wing as well as several tenant units, has commenced major renovations to its facilities to house the support computers and high-speed communications circuits that will soon be installed. An HF-GCS station consists of three major pieces: the transmitter, receiver, and the control equipment (including station infrastructure such as antennas and feedlines). Also part of the station are numerous other support systems, along with the operators and maintenance technicians, logistics support personnel, and the training system. According to the Air Force, the 319th Communications Squadron is 130 persons strong.
“The new circuits will ensure reliable connectivity to antenna locations around the world to provide secure data and voice connections to command and control aircraft.” said Staff Sgt. Russell Mullens of the 319th CS Plans and Resources Flight, quoted in a news story carried by the USAF’s Air Force Link website (www.af.mil).
Grand Forks AFB (Photo A) is a facility covering 8.2 square miles of land, located about 15 miles west of the city of Grand Forks, the home of the University of North Dakota. The actual construction of the base began in February 1956. Grand Forks was originally constructed as a fighter-interceptor air base, and initial construction was completed in 1960, when the 18th Fighter Interceptor Squadron began operations with the F-101 Voodoo. In July 1963, the base was placed under the command and control of Strategic Air Command (SAC), and became home of the 4th Strategic Aerospace Division. Added in November 1964 was the nation’s first Minuteman II intercontinental ballistic missile (ICBM) wing, the 321 Strategic Missile Wing, which became fully operational in December 1966 (the 321st received the Minuteman III upgrade in 1973).
Shannon’s Broadcast Classics
The Fire Tower DXpedition Contest Of ’79
by Shannon Huniwell
My long-suffering junior-high math teacher had a sign over his desk urging, “Hire a teenager now…while he or she still knows everything!” That may be a bit of an exaggeration. But the former adolescent—and present day Pop’Comm reader—who gave me his story for this month’s feature admits that a youthful know-it-all attitude was largely responsible for his first frostbitten foray into the radio hobby.
Nick Ventner remembers being plunked into a 9th grade class at the rural Elizabethtown (New York) Central School sometime in mid January 1979. His single parent father had found construction work in Florida so sent him to stay with an elderly aunt and uncle who had a winterized camp on Lincoln Pond about six miles outside of what the Adirondack natives called “E-Town.” On that first day in the new school, he sat alone at lunch wishing for a buddy to talk with, but felt better that nobody came close enough to notice him nibbling on Meals-On-Wheels leftovers.
Just before the bell rang, though, a chubby-cheeked kid perusing a magazine absentmindedly wandered over his way and plopped down. He was one of those readers who silently moved his lips.
“What’s so interesting?” Nick asked.
Matter-of-factly, the boy responded with three words, “Distant Radio Stations.”
The next day, Nick’s new acquaintance was more talkative. During lunch, he identified himself as Chippy.
“Kids call me that because I have a fat face,” he stated with an air of resignation. “To them I guess I don’t look like I’m good for much, but I’ve got my hobbies.” With that, he pulled his magazine out of an army surplus knapsack. “I get paid in books and stuff from an old lady next door I do odd jobs for. Last week, she gave me a box of printed matter, including this publication from nearly 20 years ago.” He held up the spring 1960 edition of Radio-TV Experimenter and then from its recesses pulled out a black & white snapshot. “I’m aiming to pick-up the station in this picture here,” he announced in a high-pitched voice that’d surely annoy anyone not particularly interested in what the kid had to say. “It’s way out in Chicago.”
The top of the little publicity still had long been stained with a rusty staple gripping several tightly typed paragraphs from National Broadcasting Corporation’s public relations department. Its headline read, “WMAQ To Step Up Power.” Full of superlatives, the copy boasted:
WMAQ’s 50,000 watt transmitter will begin operation Sunday September 15, 1935 replacing the old transmitter in use by the pioneer station since 1928. The 490-foot, 3-sided, non-tapered vertical radiator—first of its kind in the Country—is topped by a 60-foot capacity top tuner—the largest ever built. The tower has received its coat of alternate orange and white paint to safeguard daytime flyers. At night, ever burning marker lights and revolving beacon are used for illumination.
Ask most people where the best AM radio reception might be found, and they’ll instinctively point upwards. That’s probably because when folks think “radio broadcasting” tall towers come to mind. Following that logic, many assume that the higher the receiver is situated, the better its antenna will snag signals.
THE LIGHTER SIDE
The Loose Connection
To Scare A Mockingbird
by Bill Price, N3AVY
My entry into vandalism (that’s such an evil
word) began when I read a story of a kid sneaking out at night, doing all
sorts of devilish things in his neighborhood, and then sneaking back home
undetected. My two best friends (I so much want to call them Flick and
Schwartz) must have read the same story or one just like it because it was
not a week after my “awakening” that they each, separately, told me of
their nocturnal adventures.
Larry would go out hunting for raccoons with a slingshot and his trusty dog, Jinx. Jerry had other things in mind and took off on his bike at about 11:00 p.m. and rode almost an hour to a nearby town where he ditched the bike and hung around on a street corner, smoking cigarettes and swilling soda with the “big kids.”
Larry had a landlord that neither of us liked, and neither of us had the good sense to leave him alone so that Larry’s folks could live in peace. Larry was particularly mean, and I was particularly devious. We were made for each other.
So all we had to do was make it look as if—whatever happened—we were not involved. This meant we couldn’t be blatant and put food coloring in his swimming pool—something I’d wanted to do for a long time. He drove a sports car. There was no lock on the trunk. This was textbook. We would flatten his spare and one of his tires and hide the tire pump which he kept in the garage. To avoid doing too much late at night when all was quiet, we hid the pump under a pile of junk in his own garage during the day.
Now Larry and I had to meet at some time and place, but neither of us could be sure just when we could get out of the house, with parents watching late-night TV or otherwise up and about. I’d already been drooling over surplus walkie talkies, but even if I could have afforded a pair I’d have needed a bank loan to get the batteries. Also, at our age and size, we probably couldn’t have carried them for long. These were the same ones our lead toy soldiers (with lead-based paint) carried.
We’d learned that since our phones were on a
party line, all we had to do was pick up the phones at the same time (we
synchronized our watches) and dial 1 to get rid of the dial tone. That
way, there was no ring for our parents to hear. We spoke of our plans on
this very same party line in whispered tones almost every day that week.
Friday night was the night, and 11 o’clock was the time we’d pick up the
phones. (DETECTIVE ALERT! This is the paragraph which Hercule Poirot would
quote when exposing the perpetrator(s) to Captain Hastings and inspector