The Weirder Side Of Wireless
Free News Is Good News
Why go looking for bad news when you can let
it come to you? According to an article in the Patriot-News, residents in
Lower Paxton Township (Pennsylvania) have the option of signing up to
receive crime updates. Township police have started using Nixle, a free
service that lets them send text messages and emails about criminal
incidents to residents who sign up for it. Updates might cover a rash of
car break-ins or suspects on the loose. The difference between Nixle and
social networking sites such as Facebook and Twitter is that Nixle is more
secure and more geographic, says Nixle founder and CEO Craig Mitnick. “It
gives them the ability to push unfiltered information to the exact
residents it’s relevant to,” say Mitnick as quoted in the article. Nixle
is free to government agencies, but text-messaging rates apply to anyone
who signs up for the service. The borough’s mayor, Tom Acri, said feedback
from residents has been positive. “It’s been a good experience and a free
experience. If more communities use it, it may stay a free site,” says
Acri is quoted as saying.
It’s the kind of story more suited to the pages of “Shannon’s Broadcast Classics” than a police blotter. Associated Press writer Nigel Duara reports that a handwritten letter with a phony return address arrived at a Catholic college in Iowa last November and opened a door into a long-forgotten mystery. The author was seeking forgiveness for a crime so minor, no one could recall it. But the thief didn’t forget, and slipped five $100 bills into the envelope as repayment for a portable radio that must have cost only a few dollars when it was stolen in 1955 from a teacher’s lounge at Clarke College in Dubuque, Duara reported.
The penitent purloiner penned, “I have regretted this foolish act ever since and have resolved many times in these past years to make restitution,” he or she wrote. “I’m ashamed that it has taken this long to turn resolve into action.”
The letter writer requested that the money go toward “the comfort of your current faculty members and ask them to forgive me, and join me in praying for God’s forgiveness as well.”
The letter offers few clues to the thief’s
identity. The person was on campus in the mid-1950s, and the letter
carried a Chicago postmark. Perhaps Shannon can solve the mystery.
News, Trends, And Short Takes
by D. Prabakaran
BBG Says Its Broadcasts Still Attract Large Audiences
U.S. international broadcasting attracted wide audiences worldwide in 2009, particularly in key countries including Iraq, Afghanistan, and Iran, despite declines in press freedom and the targeting of journalists in some countries, the Broadcasting Board of Governors (BBG) announced. More than 171 million people worldwide turn to U.S. international broadcasts across media platforms every week for news and information, according to the BBG’s independent research. This figure is statistically unchanged from the BBG’s global audience estimate of 175 million reported in June 2008 and represents an increase of more than 70 percent over the 100 million listeners and viewers in 2002.
Countries with the highest percentage of audience reached include Iraq (72 percent), Rwanda (72 percent), Kosovo (64 percent), Afghanistan (56 percent), and Haiti (50 percent). Audiences increased to a record 43 percent in Armenia and to 16 percent in Zimbabwe.
The largest audiences for U.S. international broadcasting include Nigeria (22 million), Indonesia (16 million), Iran (14.5 million), and Iraq (11.7 million). The BBG’s first-ever survey of Niger found an audience of nearly 3 million in that country, while the first nationwide survey of Haiti found 1.4 million listeners. The audience also increased by 1.4 million in Egypt.
In many countries, audience samples are
extremely limited and require audience members to acknowledge illegal
listening and/or viewing, activities that result in severe penalties.
Numbers for these hard to reach countries and regions, such as Somalia,
North Korea, Tibet, and the Xinjiang Uyghur Autonomous Region, are not
included in the overall estimate. Such restrictive environments may make
survey participants reluctant to reveal media habits that include banned
Capitol Hill And FCC Actions Affecting Communications
by Richard Fisher, KI6SN
Updated Amateur Radio Technician Class Question Pool Released
A new pool of test questions for the
Technician class of FCC-issued amateur radio license has been released to
the public and goes into effect with examinations beginning July 1. The
Question Pool Committee (QPC) of the National Conference of Volunteer
Examiner Coordinators (NCVEC) had released the new questions to the 14
Volunteer Exam Coordinators (VECs) in December 2009. The pool was made
available to the public in January 2010. Each pool of questions for the
Technician, General, and Amateur Extra classes of licenses is “reviewed on
a four-year rotation,” according to a report from the American Radio Relay
League. “This new Technician class pool will become effective on July 1,
2010.” The pool will remain in effect until June 30, 2014.
A $5,000 FCC Notice of Apparent Liability
against a Southern California church-affiliated FM station that prompted
protests from broadcasters who alleged the Emergency Alert System “is
prone to errors, and that the station did not intentionally improperly
transmit the botched test” has been rescinded by the Commission, according
to published reports. Calvary Chapel of Costa Mesa, California, the
licensee of KWVE-FM, was cited for “transmitting an incomplete required
monthly test,” a story on Radio Magazine Online reported. “The station
also tried to remedy the error without success.” Although the NAL was
withdrawn, KWVE-FM was “admonished for transmitting an unauthorized RMT
(required monthly test) of the EAS and failing to transmit the End of
Message code as well as the message advising that the test had been
Sorting The TV Sources
by Rob de Santos
As a friend often reminds me, her rural community had one TV station and no cable service until well into the 1990s. Of course, that was the exception. By the middle of the last decade, most of us had access to dozens of channels via cable or satellite. Now, it’s hundreds. Add to that the myriad other sources of video and the TV landscape is changing rapidly.
The transformation of the video business is accelerating and we’re entering the “second phase” of the technology. It’s been less than one human lifetime since the transmission of moving pictures and sound by electromagnetic waves was invented. It was 20 years before a convenient means was available for recording programs off the air and another 10 years before that technology was a readily available consumer product in the form of the VCR. In the ensuing several decades, we’ve seen the development of the DVD, HD television, DVR, PVR, YouTube, and more.
Where are we today and what’s available now? Following is just a small sampling of the products and technologies currently emerging. There’s 3-D television, which I discussed in a prior column. There’s the Internet as a delivery medium (you can subscribe to a few Internet-delivered “cable lineups” now). TiVo and dedicated interface boxes like the Roku Digital Video Player and the Apple TV provide another delivery method. And if you have the money and the time, you can use a PC or network hard drive to stream video to your TV (that’s getting easier with the newer computer operating systems). Fiber optic is slowly replacing coax cable and most television delivered to a home travels over both before it gets to your TV. Of course, there’s HD TV sending electromagnetic waves to your TV. I’m sure many of you have “smartphones” and can watch TV on your telephone or PDA. And I haven’t touched on the personal computer applications.
Where is video delivery going? What will it be
like in five or 10 years? It’s safe to say that in the next few years
we’ll continue to see growth in the variety of delivery methods with
almost all the new entrants using the Internet in one way or another. The
use of wireless delivery (wait, isn’t that radio?) will also be a major
factor in the near term as 4G cellular networks begin to roll out widely.
Not all of these options will prove to be cost effective or good business,
and it’s like that we’ll see considerable differences from one country to
X-DX: Extreme DX For The
Mr. Webster’s dictionary offers one definition of the word “masochist” as someone with “a taste for suffering.” The more serious SWLs among us will qualify, at least a little. The very serious ones, the extremists, or X-DXers, are hardcore. We relentlessly tune around the bands, check our want lists, and read club bulletins, magazine columns (it had better be you-know-what!), and hope against hope for improvement—if not today, then certainly tomorrow or the next day! Our lives are practically ruled by the propagation reports on WWV and what they can do for us, or to us. In the end we have to agree that we’re all a bit masochistic, whether we care to admit it or not.
The real certifiable X-DXer isn’t troubled at all by a lack of signals from juicy DX targets. For him a complete absence of sunspots is a shot of adrenaline. He may have an affliction, but you gotta hand it to him—he’s the one holding the line and making tackles when there’s only a minute left in the game and his team is down by seven touchdowns, the one still trudging toward the highest peak after everyone else has collapsed!
So let’s hear it for that masochist, the X-DXer.
He’ll likely be the first to notice the turn around when (if?) it comes.
To encourage a continuation of his battle—to keep him pounding away, here
are a couple of dozen of what would be “impossible dream” catches,
designed to keep our suffering hero happy. He can flail and claw at them
from now until conditions either get very much better or Brother Stair
leaves the air—whichever comes first.
Now, let the frustrations begin!
We start with Radio Municipal, 3172, in Panao, Peru. Some authoritative listings aren’t even sure what power this station uses; I think it’s about 1 kW, probably less. Being a domestic Peruvian you can be sure its programming is all in Spanish. It has a fairly full broadcast day, 0830–0400. Any reception at all is totally dependent upon openings that reach deep into South America, which are few and far between. Panao is in Pachitea Province, in Huanuco State.
Same name, different country: Radio Municipal, Sao Gabriel, Brazil, uses 3375 with Portuguese programming from 0900–0100 (Monday–Saturday) and all week from 1000–1300 and 2100–0300. Sao Gabriel de Cachoeira is in Amazonas State. It is rated at a whopping 5 kW, so that increases your chances by about the width of a Wahoo whisker.
The Voice of Iranian Kurdistan is one of those clandestine or opposition or target broadcasters—place it in whatever pigeonhole you choose. This involves entering the treacherous 75-meter ham band at 0300–0400, a high-traffic time when the hams are busy exchanging 5/9s. This station, using 3970, is thought to operate from the Kurdish portion of Iraq and has a contact office in Paris.
You think that one was tough? Then this one
will really raise the gooseflesh. The Voice of Jammu-Kashmir Freedom,
operating on 3975—that’s just 5 kHz up from the previous one you couldn’t
hear. It’s another clandestine type, based in Pakistan and broadcasting
for some hours in English (so they say). The station is active from
0245–0715, 0745–0845, and 1300–1430. It’s also listed for operation on
3995, 5990, and 7230, but these don’t appear to be at all active. Other
languages in use are Urdu, Hindi, and a couple of others none of us has
ever heard of.
In-Depth: The FlexRadio FLEX-3000 Software-Defined Radio
by Dan Srebnick, K2DLS
Software-defined radios (SDRs) are all the rage. Last year, I had the opportunity to evaluate the Perseus SDR from Italy, and took so much of a liking to it that it replaced the Drake R8B as my general coverage receiver in the shack. The next logical step on this technological journey seemed to be a software-defined transceiver.
The HF transceiver in my shack is the
mid-class Kenwood TS-2000. The design is beginning to show its age,
especially with limited capabilities of the early 16-bit digital signal
processing (DSP) filters. Moving the demodulation and processing of
signals from hardware to software is an excellent way to adapt to new
algorithms and techniques in audio processing and filtering, without
hardware modification. Flex Radio Systems (<www.flex-radio.com>)
is the leader in manufacturing low- to high-end amateur radio transceivers
that do most of their work on your personal computer. I recently was able
to spend a few weeks with the FLEX-3000, a middle-of-the-line SDR
The transceiver itself is very low profile, as seen in Figure 1. It is 12 1/4 inches square and only 1 3/4 inches tall, so it will easily fit on your radio desk. You could even put a laptop that will run the software on top of the box, although that might not result in the most comfortable operating position. A flat panel monitor fits on top of the FLEX-3000 box with no difficulty.
Power output is 100 watts PEP and the 3000 is rated for full duty cycle at that power, making this radio a good candidate for digital modes like PSK31 and RTTY. Transmit coverage is from 160 to 6 meters, and the 3000 includes an internal antenna tuner. Receive range is from 10 kHz to 60 MHz. The panadapter display (Figure 2), a visual spectrum representation used in SDR software, is capable of displaying up to 96 kHz of spectrum concurrently and in real time. Transmit and receive filters are continuously variable through software and can be tailored to the operator’s requirements.
The FLEX-3000 does not have some of the
advanced features of its big brother, the 5000. It lacks things like a
second independent receiver, VHF/UHF capability, and transverter support.
If you need any of these advanced features, the 3000 may not meet your
requirements and perhaps you should take a look at the FLEX-5000.
Global Information Guide
Radio Prague And Other
by Gerry L. Dexter
Perhaps Pop’Comm’s production department should start making occasional use of black borders! Radio Prague was scheduled to end all of its shortwave broadcasting at the close of last year. If that has indeed happened, you have already found the station missing from its usual frequencies. There were serious pressures on its budget as 2009 edged to a close, and the broadcaster had to absorb a 20-percent cut in its budget for 2010. The Czech government has gotten itself caught up in the “shortwave is old fashioned” mentality that is such an “in” thing in Europe these days, so word came down from the Foreign Ministry “suggesting” that Radio Prague end its international service at the end of 2009.
At this writing (November) there’s just a very slim chance of retaining Radio Prague on shortwave, but the station need your letters and emails of support, just in case. Incidentally, the loss of Radio Prague would also mean the closing of the Litomysl transmitting site! Here’s the contact information: Email: firstname.lastname@example.org; Postal address: Radio Prague, Vinohradska 12, 120 99 Prague 2, Czech Republic. Do your part!
Down the tubes goes another shortwave station.
The Fundamental Broadcasting Network’s WBOH in Newport, North Carolina,
has called it quits. There’s been no explanation for the closure; however,
just a month or two ago they were warning of impending problems due to a
lack of financial support. So, what happened wasn’t exactly a surprise.
You have to wonder whether such negative news doesn’t give pause to those
folks who are about to try the same thing!
Bad news of a lesser sort: Radio Vlaanderen International (RVI) has left shortwave. Due to previous cutbacks, it wasn’t often reported in the U.S.—largely due to its unhappy schedule, which was primed for a European audience. Even if you were up in the middle of the night or could get away from work or school on an afternoon, its frequency choices were not at all amenable for us in America.
SIBC, the Solomon Islands Broadcasting
Corporation, has re-energized 5020, which had been silent for many months
but is now being heard by some well into the early morning hours. Keep in
mind that there are numerous breaks in its schedule. Its 31-meter band
frequency, which returned a year or so ago, appears to have gone quiet
again. Listed for 9545, more often than not, it was found to be hovering
around 9541. Could it be fixing its frequency?
C. Crane CCRadio-2 AM-FM/Weather Band/ 2-Meter Ham Radio
by Jeffrey Reed
I have a confession to make: I’m a late-night AM radio talk show junkie—always have been, even as a child. It started with AM 1100 WWWE Cleveland and jock talk with Pete Franklin. That station is now News Radio WTAM, and it still powers its way across Lake Erie and into my hometown of London, Ontario, Canada (sitting halfway between Detroit, Michigan, and Toronto, Ontario).
My insatiable appetite for AM radio is a major reason why I entered the field of broadcast journalism, and later freelance writing. As a kid, I wish I’d been armed with the new C. Crane CCRadio-2, the newest addition to my ever-growing shack. In fact, as soon as I began to decipher the functions of this attractive AM-FM radio with Weather and 2-meter Ham Bands, it found a permanent spot on my nightstand. And Coast To Coast AM with George Noory never sounded better.
My shack includes a handful of C. Crane gear,
including the CCRadio SW, which offers outstanding DX listening and superb
voice clarity. I now make room for the CCRadio-2; it picks up right where
the CCRadio SW and the legendary CCRadio leave off.
If you’re like me, the first things you look for in a quality AM-FM radio are signal power and voice clarity. The C. Crane CCRadio-2 boasts both in spades. Add the Weather Band and 2-meter ham functions, and you have one heck of a radio, perfect for any room in the house.
Weighing in at just less than 4 pounds without four “D” batteries, and measuring 6.5 x 11 x 4 inches (HWD) at its base, the CCRadio-2 is available in both black mica and titanium models. The design aesthetics are gorgeous, making this radio perfect for the home office, living room, or anywhere else you wish to listen to crystal-clear radio transmissions.
The first test I put to the CCRadio-2 was
late-night DX on the AM side. WRVA 1140 in Richmond, Virginia, WJR 760
Detroit, and WCBS 880 New York, all came in crystal clear on an
early-August evening. C. Crane really has something in their patented
Twin-Coil Ferrite AM antenna. A quick flip to the FM side and one of my
favorite local stations, 92.7 FM BX-93 in London, Ontario, revealed some
of the sweetest sounding FM stereo I’ve ever heard from a portable radio.
The 5-inch speaker made the vocals of Country Music artist Taylor Swift
sound even sweeter than usual, thanks to audio which is optimized for
voice clarity. In fact, when you select a station, the CCRadio-2 evaluates
the signal for several seconds and then locks in for the highest signal
Getting Maximum Mileage Out Of The Solar Minimum On The AM Band
by Bruce A. Conti
The prolonged solar minimum has resulted in
unprecedented conditions for reception over long distances on the AM
broadcast band. Japan has become a regular visitor to the East Coast of
North America, while Europe is being received in the west. Conditions
aren’t everything though. Knowing when to listen can be just as important.
The critical time periods to monitor are the transition zones of dusk and dawn for both the receiver site and transmitter site. Reception is enhanced when the receiver and/or transmitter sites are within the dusk/dawn transition zones. Further enhancement is possible when a signal follows the path along the transition zone from the transmitter site to the receiver, referred to as grayline reception. GeoClock, distributed as shareware via <www.geoclock.com>, is an indispensable tool to help identify potential DX target areas in the sunrise/sunset transition zones. It provides a map of the Earth overlaid with areas of sunlight and darkness along with sun and moon positions, continuously updated in real time. The map can be customized with target transmitter sites and locations, as in the examples shown here. An optional “Ham” function provides a Great Circle map centered on your receiver location.
This month we’re going to show you a couple of examples of how sunrise and sunset times can be used to identify good DX target areas. Here Saturday, February 13, sunrise and sunset for Boston and Seattle are compared.
On the weekend of February 13, sunset in Tokyo, Japan, is at 0820 UTC, while in Boston, Massachusetts, sunrise is 1145 UTC; therefore, reception of Japan is possible anytime within the 0820–1145 UTC window. However the best signals are often received during transmitter site dusk and receiver site dawn, so look for the strongest signals around 0820 and 1145 UTC, typically with readable signal peaks not lasting more than 10 to 20 minutes. South Korea sunset is later, at 0911 UTC in Dangjin, leaving a smaller window of opportunity for East Coast North America DXers, with perhaps the best chance during transmitter site dusk after the Japan sunset enhancement has passed. VOA Thailand is a favorite target on 1575 kHz, but the window of opportunity is narrow with transmitter site sunset at 1121 UTC, leaving only a few minutes to try to catch this signal before Boston sunrise.
For West Coast North America DXers, reception of signals from Europe is more dependent upon transmitter site sunrise. Though some of the more powerful signals can be received during West Coast sunset enhancement, often European signals are strongest during transmitter site dawn enhancement. DXers in Seattle, Washington, can begin checking for signals as early as local sunset at 0130 UTC on February 13, but peak signals likely won’t show up for a few hours. High power signals from Croatia and Kaliningrad may not be received until transmitter site sunrise around 0600 UTC. Reception of western European stations like France Info on 1206 kHz or Absolute Radio from the United Kingdom on 1215 kHz, may not peak until transmitter site dawn or after 0700 UTC, shortly after which transpacific signals from Japan will begin to appear. Similar to reception of Japan in Boston, readable peaks of European signals on the West Coast may only last 10 to 20 minutes before fading out with transmitter site sunrise.
Specific sunrise and sunset times can be obtained through the U.S. Naval Observatory website at www.usno.navy.mil/USN. Once at the website, select “Astronomical Applications” where complete sun and moon data for one day or a sunrise/sunset table for one year can be obtained for a particular location identified by coordinates. A link is provided for the GEOnet Names Server to determine coordinates if unknown.
by Ken Reiss
This month “ScanTech” looks westward with a focus on the Beaver State’s statewide police system and agencies serving its largest city, Portland, and its environs.
The Oregon State Police, officially called the OSP, was formed in 1931, making it a relative latecomer to state police agencies. By contrast, the Portland Metropolitan police were up and running in 1870, so the state agency is quite young by comparison.
A commission appointed by then Governor Julius
Meier conducted a survey of leading law enforcement agencies across North
America, including the Royal Canadian Mounted Police, New Jersey State
Police, and the Texas Rangers, with the goal of building on their
successes. Based on the findings, the OSP was established to combine the
law enforcement responsibilities of the State Highway Commission, Fish and
Game Commission, Secretary of State, the Fire Marshall, and the
Prohibition Commissioner. Its primary mission in the early days was to
serve as rural
Today, the OSP is divided into three
divisions. The first, Public Safety Services, includes State Fire Marshall
and Gaming, Forensics, Dispatch, and the Medical Examiner’s office. The
Police Services Division includes Patrol and Criminal investigative units
and Fish and Wildlife. The third, the OWIN, or Oregon Wireless
Interoperability Network, is an initiative of the state legislature to
combine the state’s four major radio networks into a statewide system of
Shannon’s Broadcast Classics
Trains And Boats And
Planes...Several RF Signal Sagas
by Shannon Huniwell
It’s almost embarrassing to admit that a swift bump from a quickly closing, cold, glass shower door on a sleepy Saturday morning served as the idea starter for this column, but that’s what happened. The jolt elicited a startled high-octave note or two, which in the shower inexplicably morphed into a tune I’d not thought about for years: the 1960s Burt Bacharach classic, “Trains and Boats and Planes.”
We’ve all experienced having a song stuck in
our heads. It can be annoying, but sometimes the music brings back
forgotten memories or generates new ideas. As usual, I’d been fretting
over a Pop’Comm topic, but after only about three soapy encores,
inspiration hit as the lyrics got me thinking about histories of broadcast
stations that were based on the transportation trio named in Bacharach’s
Top-40 hit, hauntingly sung by Dionne Warwick.
The train component of our story begins with dusty paperwork from the Radio Division of the U.S. Commerce Department’s Bureau of Navigation. According to these documents from 1924, the Third Avenue Railway Company of New York City proposed building a 500-watt broadcast facility, a notably large power request for that era. In its application, Third Avenue Railway billed itself as a “utility carrying 350 miles of track” throughout the Big Apple. In simpler parlance, the organization operated a fleet of trolley cars vast enough to require some 3,000 employees to staff its line. Because of the firm’s electrical focus, Third Avenue Railway technical gurus envisioned a novel way to communicate to their workers aboard the trolleys. They commissioned General Electric to rig up a one-way carrier current transmission system that sent voice through the network of overhead drive wires to each trolley car.
Originally, the content of the closed-circuit programming was limited to information germane to the folks running the trolleys. In short order, however, company bigwigs saw immense opportunities in being able pipe programs to the passengers from the trolley outfit’s headquarters, via a bigger amplifier and speakers placed throughout the cars. After this 1923 closed-circuit installation was deemed successful, Third Avenue officials figured a reception footprint larger than the track boundaries would net the company an even wider range of public relations possibilities. That’s where the radio station concept came into play.
In its efforts to establish a true
broadcasting arm, the transport company’s secretary, Garrow T. Greer, was
identified as the radio venture’s “executive director.” A governmental OK
to construct the proposed station was granted in July 1924. Almost
immediately, work began on the installation of a pair of 60-foot
self-supporting steel towers on the roof of Third Avenue’s “car barn and
executive offices located at 130th Street and Third Avenue.” Between the
cross-hatched lattice style pyramids was strung a T-type wire antenna.
Electrical oversight was the job of W.J. Quinn, who normally served as the
company’s chief engineer. Along with the technical authorization for Third
Avenue’s radio enterprise, Government officials bestowed the callsign WEBJ,
a simple sequential issue by the Radio Division that didn’t stand for
THE PRACTICAL SIDE
The Propagation Corner
Change We Can Count On
by Tomas Hood
It was year of change. During the first half of 2009, it looked doubtful that Sunspot Cycle 24 had any life, or any hope for change. However, as reported last month in this column, the sun began to show signs of waking up from the extended period of sunspot slumber. Solar observers have resisted getting too excited about any solar activity, because the sun has fooled us already during this cycle minimum; we’d see signs of life with a sunspot region emerging, only to see it fade away quickly, leaving a spotless sun for another few weeks. October’s grand sunspot showing was not enough to convince the once-bitten, twice-shy heliophiles.
Then came November and increased solar activity. Only the first four days in November were spotless. Five days with a zero sunspot (October 31 through November 4) ended with the arrival of an official new active sunspot region on November 5 (Figure 1), numbered 1030 by the National Oceanic and Atmospheric Administration (NOAA). At the same time, another region appeared to the south of 1030 and looked like it might develop into an actual group of sunspots. The official Space Environment Service Center (SESC) sunspot count on November 5 was 15. Both areas were small compared to the sunspot region that just rotated out of view at the end of October. By the next day, the count reached a maximum of 16. Two days later the sunspot count was back to zero. Heliophiles around the world thought that things were going back to “normal” for this sunspot cycle minimum: no spots for days on end.
This dismal outlook was cut short on November 9 when sunspot region 1030, thought to be dead and gone, flared up with a sunspot count of 14. This region was active until November 12, and the next day was again spotless. Heliophiles turned skeptics once more, pointing out how small this active region was compared to the region seen during the end of October.
Little by little, the period of days with zero sunspots is becoming shorter than we’d seen during most of the current solar cycle minimum. The sun delivered another sunspot region that yielded a sunspot count of 11 on November 15 and 12 on the 16th. The official count on the 17th was zero, but by the 18th the count was 29, and that started a run of daily sunspot counts (Figure 2). Clearly, November was more proof of what I’ve been forecasting: by the end of 2009, we’ll witness the waking up of our nearest star, and sunspot Cycle 24 is alive and well.
During all of November, the 10.7-cm flux
remained above 70. This slight and welcomed increase in daily flux
activity, combined with the expected yearly improvement that comes each
autumn, resulted in very good conditions on the shortwave frequencies.
During the rest of November, the sun remained active (Figure 3). Will this
activity die away again? Or are we now seeing the sure and steady monthly
rise expected at the start of a new sunspot cycle? Is Sunspot Cycle 24
here to stay, and did 2009 indeed end as a year of true change? Keep
checking this column each month for progress reports.
Special Event Stations: Fun To Work, Fun Stuff To Collect
by Kirk Kleinschmidt, NTØZ
Although I’ve been called a packrat (or less complimentary versions of the term), I prefer to think of myself as a collector! The thousands of electronic parts, doodads, and QSL cards in my office/shop aren’t disgusting lumps of detritus piled carelessly by a packrat—they’re lovingly cared for historical assemblages maintained by a sophisticated collector. Or maybe even a curator.
You’re probably reaching for your hip waders right about now, so I’ll ease off on my personal illusion. My point, though, is that most hams collect stuff. Most hams have some interest in the historical perspective of radio and all its wonders. And even if we don’t all have the space or the financial ability to collect vintage radios or early De Forest Audion vacuum tubes, we still collect interesting ham stuff, as we’re able.
As a teenage ham I would marvel at the photos in the ham magazines that showed hams with huge collections of QSL cards and operating achievement awards. Of course, these were proudly displayed on the walls of each shack. Some collections were so large that there was virtually no blank space on any of the shack’s four walls! With a magnifying glass I could often make out callsigns, DXCC certificates, etc.
This is the stuff that drove me to get in the game as a brand-new 15-year-old ham. I wanted to collect that special, memorable stuff myself. I also wanted to plaster the walls of my bedroom/shack with the same stuff, which made my mom a bit crazy. Apparently, tape marks, leftover adhesive, and hundreds of thumbtack holes in the paneling weren’t things she could embrace as a “non-collector.” We compromised a bit, and I displayed only the most interesting parts of my “collection” in a somewhat contained area just to the right of my operating position. (You’ll hopefully have more room!)
As a beginning ham you probably know about operating achievement awards, QSL cards, and contest certificates (which I discuss here periodically), but you may not know about another type of “wallpaper” that’s even easier to collect—and just might capture the imagination of your mom (spouse, whomever) and other non-hams. I’m talking about Special Event certificates. And unlike contest awards and other “achievement” awards, no great feat of skill or endurance is required. You simply have to contact the Special Event operator on your favorite band and mode (or more than one), and you qualify. A trophy for your collection will soon be forthcoming.
This is fun stuff, and it’s the topic of this
month’s column: Special Event wallpaper and how to get some.
Special Events are on-air activities designed
to generate interest in specific happenings. Clubs or groups try to
contact as many people as they can in a given time period (usually the
course of a weekend), and they produce special QSL cards and/or
suitable-for-framing certificates to issue to the operators they work
(that’d be you!).
THE PRACTICAL SIDE
The Wireless Connection
Vacuum Tube Voltmeters—Handy And Handsome
by Peter J. Bertini
and available, the venerable vacuum tube voltmeter (VTVM) continues to be a staple on many workbenches. My faithful Heath IM-13 has been doing duty since I was in junior high school in early 1960s. VTVMs are somewhat obsolete, but there are valid reasons for their long-lasting popularity.
The earliest DC voltmeters were simple devices. They resembled a large pocket watch, and were used for measuring B+ and filament voltages in early battery sets, but you’d have to use a different meter for each battery type! Later models incorporated a range switch, where a single meter scale might serve for the different voltage range selections. For example, a meter with 0 to 1 scale could be used for decade voltage steps of 1, 10, 100, and perhaps 1000 volts. A switch selected the appropriate dropping resistor for each voltage range. A voltmeter using 1-mA meter movement would have a total internal series resistance of 50,000 ohms on the 50-volt range; and that also means the meter had a 1000-ohms per volt specification.
There’s no magic here: it’s all based on simple Ohm’s Law math calculations, and this resistance was the combined value of the switch-selected fixed resistance and the internal resistance of the meter’s moveable coil winding. The meter’s moving-coil resistance is relatively small (a few hundred ohms at most), so the fixed resistor for that range provides the majority of the resistance, especially in the higher voltage ranges.
Unfortunately any voltmeter (except a differential type) will load a circuit while taking a voltage reading. There isn’t a problem when measuring the power supply voltages, but a 1000-ohms-per-volt meter will greatly influence the automatic gain control (AGC) bus, or screen or control grid bias measurements. As a rule, early schematics included voltage readings in an effort to assist with troubleshooting. More importantly, the ohms-per-volt rating for the voltmeter used to make those readings is also given.
The error is greatest when reading voltages on
control grids or screen grids that a feed from a dropping resistor. For
example, a typical screen-dropping resistor might be 75,000 ohms. Taking a
screen voltage reading with a 1000-ohm-per-volt meter set to the 250-volt
range would be the same as wiring in a 250,000-ohm resistor from the
screen to ground. It would form a voltage divider with the 75,000-ohm
dropping resistor, and the meter would display a lower-than-actual voltage
reading. There are other dynamics at play, the screen current would change
as the voltage changes, making the end results even harder to predict.
I’ve noted this in the past: It is important to understand the limitations
of your test equipment and how their application affects measurements. AGC
bus voltages are extremely sensitive to external loading.
THE PRACTICAL SIDE
The Antenna Room
Antennas And Electronic Warfare
by Kent Britain, WA5VJB
This month, and for the next few columns, I’m going to talk about (as much as I’m allowed to) some different uses for antennas in electronic warfare. It’s a fascinating subject, even if it does fall into the “don’t try this at home” category.
While it’s been some time since I attended one of our support group meetings, I’m what is known in the electronic warfare industry as an “Old Crow.” This term goes back over 60 years, and is colorfully described by the Association of Old Crows (AOC) as follows: “An Old Crow flies though the sky, not because he is the fastest, or has the sharpest claws. An Old Crow flies though the sky because he is the wiliest.” In short, if I understand how your radar-controlled missile, gun, etc. works, I can moon you as I fly over while my equipment keeps pulling off your range gate, preventing radar lock. Clear? Anyway, moving on…
In Photo A we have an Archimedean Spiral Antenna. These are very popular antennas in electronic warfare because of their wide frequency range. The lowest frequency they will operate at is determined by the diameter of the antenna. The highest frequency is determined by how precise you can make small spirals in the middle of the antenna. A frequency range of 2 to 18 GHz is common; 1 to 40 GHz is possible.
The downside of these spirals is their low gain, usually in the -2 to -20 dBi range. To keep the housing or cavity behind the spiral from resonating, the cavity is usually filled with a radar-absorbing material. I’m currently building this particular spiral for a Radar Decoy. The spiral has an impedance in the 150 to 200-Ohm range; the hard part is coming up with a 50 to 150-Ohm impedance matching circuit that works from 2 GHz to 18 GHz. The low gain of the cavity-backed spiral gives it few civilian uses, but its flat geometry allows the antenna to be mounted flush with the skin of an aircraft. And, when detecting radars, low antenna gain is not a problem.
To help you understand how it works, imagine that you’re in a large flat area, such as a Kansas wheat field or a dry lakebed, on a dark moonless night. A flashlight is your radar transmitter, and your eyes are your radar receiver. How far can you see a person with your flashlight? One hundred feet? Maybe 200 feet? Now reverse this. How far away can you see someone holding a flashlight? One mile? Five Miles? This is how a police radar detector can pick up that speed trap on the highway long before Smokey can get your speed.
The same is true for aircraft: the electronic
equipment on the airplanes can detect and identify radars long before the
radars can see the airplane. That’s why an airplane can have -20 dBi
antennas and still hear radars just fine. What’s important is that the
equipment on the plane can hear all radar bands.
Utility Communications Digest
Receiving Worldwide Weather Info Via HF FAX
by John Kasupski, KC2HMZ
For those of us who have interfaced our radios with our computers, the door to a whole new world of utility monitoring targets has been opened. We can receive transmissions in numerous digital modes using the same equipment, and perhaps best of all, much of the software we can use for this purpose can be run on older computers running older operating systems—we don’t have to have a new monster computer with the latest OS. After we buy a new machine to replace an aging family PC, the old one often makes a good “shack computer,” and best of all, our family members won’t be complaining about us tying up the family PC with our radios all the time!
One of the things we can do (even with a very basic computer, once we’ve interfaced our radio to the computer’s sound card) is receive weather maps transmitted by utility stations around the world through a process known as RadioFAX. Also known as HF FAX or WEFAX, this is a means of broadcasting graphic weather maps and other graphic images via HF radio. The term WEFAX is generally reserved by some hobbyists to refer to receiving weather imagery via satellite, with HF FAX being used to refer to the reception of these products on the shortwave utility bands. I myself prefer to use the term WX-FAX, since “WX” is an abbreviation for “weather” familiar to hobbyists.
According to the National Weather Service (one of the agencies that creates these products; see Photo A), the earliest broadcasts of weather maps via RadioFAX appear to have been made in 1926 by American inventor Charles Francis Jenkins (Photo B) in a demonstration for the U.S. Navy. If that name sounds familiar, it may be because I mentioned Jenkins previously in a column; or it may simply be that Jenkins is also credited with the invention of the motion picture; or that he later established the first U.S. television station, W3XK in Wheaton, MD. Be that as it may, the Jenkins invention we’re talking about here was once used for everything from transmitting newspapers to wanted posters. The broadcasting of marine weather charts is the primary application for it today.
To receive these transmissions, one can use a
dedicated FAX receiver (a rather expensive option for accomplishing only
one basic objective), or an SSB receiver connected to either an external
FAX recorder or a computer equipped with a radio interface and appropriate
software. Since the same radio/computer/software setup can receive
countless other digital modes as well as weather FX transmissions, this is
the most cost-effective method for SWLs.
THE LIGHTER SIDE
The Loose Connection
Fruits Of His Labor
by Bill Price, N3AVY
I just heard from Beezer, who is doing well
despite the best efforts of his former employer to close the doors and run
off without paying him. Beezer worked with Norm and me way back when, and
he has given me some really great tales to relate over the years. I’m
still trying to work up something I call “36 Cents and High Beams” about
the time he had to drive some hundred miles with just 36 cents in his
pocket and only high beam headlights working on his pickup
Beezer’s situation was different. He didn’t have a townhouse and no claim to any particular piece of lawn or roof. But like most hams, he would not let a little thing like that deter him from his appointed rounds, aka skeds.
With a tuner indoors and a balun outdoors, it’s a pretty well-known secret that any long wire can be made to radiate and receive if you don’t expect super performance, and I’ve worked with long wires that have been casually thrown across treetops using a slingshot, a bow and arrow, or even a good throwing arm. Beezer’s arm may not be so good, but neither is his tree very tall, rising up some 25 feet, more or less.
And it’s not an apple, or maple, or oak. No, where he’s living, the tree du jour is a fruit tree. Papaya, to be sure. And his wire is extremely fine steel wire with just a 1 or 2-ounce fishing weight on the end, because even though it’s nearly invisible, he’s got to take it down each morning before the neighbor (on whose tree it dangles) comes out for his morning constitutional, retrieves his newspaper, and surveys the neighborhood.
The winds have been pretty brisk in Beezer’s neighborhood lately. Normally, that’s not a big deal, but he’s noticed that the weight that holds his antenna in place swings to and fro all night while the antenna is busy sending and receiving signals around the world. In fact, he notices that every hour or so there’s an abrupt change in the SWR that requires him to adjust the tuner a bit. Not a big deal, he thought.
It seems, though, that the swaying of the
weight on the end of the fine steel wire causes a sawing motion, which
slices through a frond every couple of hours. It also drops a papaya every
so often, even though the fruit is not yet ripe and wouldn’t normally drop
for a few more weeks.