This radio is made for sale only in prison commissaries; you will not find it for sale at Best Buy, but you may find it on eBay.
The case is clear plastic to prevent prisoners from hiding contraband inside the radio and it runs on a single AA battery, which is one reason why it is popular with prisoners who must budget their commissary purchases carefully.
By Mike Schaffer, KA3JAW (fn20iq)
This is a follow-up to the October 4, 2013 article titled $20 Multimode Software Defined Radio.
On October 26, 2013 at 22:47 UTC (6:47 pm EDT), a negative 4.00 stellar magnitude meteor (less than a category negative 4.50 magnitude fireball) from the Orionids meteor shower caused by small fragments of comic debris from Halley's Comet streaked between the boroughs of Mountain Top and Freeland, then over Kunkletown, reaching into the Lehigh Valley in Pennsylvania.
Seconds later, its light yellow flame was seen overhead in Nazareth, then the Delaware River and finally making its way to Marble Hill, New Jersey, while blazing at a velocity of 41 miles per second (67 km/sec).
It was determined the meteor tracked 3.7 miles north of Center Square in Easton, PA.
Closest approach was 3.0 miles to the northeast when it fragmented into smaller pieces while cruising at a 45 degree inclination during its 3.5-second flight journey through Earth's atmosphere.
The Orionids meteor shower was active from October 4 to November 14, 2013. Peak nights occurred on October 21-22. Meteor rates were expected to be 50 to 75 per hour.
At the time of event on October 26, I was home in south Easton with two NTSC analog television sets turned to channel 2 with the volume set at a comfortable listening level waiting for a chance of TV-DX via Sporadic E or F2 propagation. Unfortunately neither occurred.
Something very rare did occur at 6:15 pm EDT, exactly 32 minutes prior to the meteor event stated above overhead near Easton, while hoping to catch the Canadian network CTV, call sign CKCO in Wiarton, Ontario via meteor scatter (Ms) on 55.240 MHz (minus offset) at a distance of 941 miles. Without warning the TV's audio steady background noise rapidly flared producing what sounds similar to a burst of high pressure air leaking through a cracked pipe. That effect instantly startled me for about three seconds.
Later, I realized that sound effect was not the result of a meteor forward scatter mode, but rather the ionized atmospheric gases (plasma) surrounding the meteor while leaving a vapor trail overhead. It seemed as if the meteor was exiting through the TV tube! After nine years of TV-DXing I never experienced this phenomenon!
It was this rare event that inspired me to take a more active roll in finding other techniques in meteor detection --- using the $20 STL-SDR dongle. After some experimentation, I can confirm that this inexpensive device has enough sensitivity to detect, spot and track meteors.
I would like to share snapshot images of what a meteor looks like on the SDR# (SDR Sharp) waterfall display.
The above snapshot shows the STL-SDR device tuned (red dial line) to a frequency of 55.250 MHz. On both sides of this frequency (55.240 and 55.260 MHz) you can see two vertical meteor scatter traces starting at the date/time stamp displayed at the left margin. The first trace (on 55.240) is a moderate signal strength signal from CKCO in Wiarton, Ontario, over 421 air miles distance. The second trace is a weak signal strength signal on 55.260 from CIII in Bancroft, Ontario over 320 air miles distance. More sample images can be found here on Photobucket
To detect meteors via forward scatter propagation there has to be powerful (25 kW or more)radio frequency transmitter at one end point that is on the air 24 hours a day, such as a
full-power TV facility that radiates 100 kW on their video carrier with 10 kW audio. In my technique, I am not concerned with the audio portion of the signal.
The above statement would meet half of our requirements. The US TV broadcast conversion from analog to digital went into effect on June 12, 2009, per Congressional mandate. Unknown to many citizens, there are analog US TV signals on the air since the DTV transition (currently 72 low-powered analog TV stations are on the air in the US). These stations are Class-A , low-powered translators that run from 2 watts up to 3 kW on channel 2. Again, the power is not strong enough for Ms detection.
By now you may be wondering how will we be able to find any full-power 100 kW broadcasters in which to do TV-DX via meteor scatter using the STL-SDR dongle. There is one other option to peruse. Our maple leaf friends up along the Canadian/US border have five analog TV-2 channels that remain active since their DTV analog-to-digital transition went into effect on August 31, 2011. This option has an extra advantage as there will be no US-based high-powered NTSC analog television stations to cause any radio frequency interference issues.
By the way, normal meteor scatter range is up to 1,400 miles.
Good DX!
In the previous installment of Surfin', I wrote about adding WFTU to my AM radio log, but mentioned, "Oddly, I can not find a photo of the WFTU transmitter site. Radio-Locator points to 40° 54' 48" N, 72° 39' 16" W, but I don't see any antennas at that location on Google or Bing Maps. Go figure!"
Tom Dunbar, W6ESL, sent me an e-mail that he found the antennas.
"It took some messing around, and peering diligently at the photos provided by Mapper but I finally 'found' the 2 antenna array for this station.
"The two antennas are very difficult to pick out of the overhead photo - they are now\t in a neatly mowed field, but are in trees / scrub / brush where an old Drive In theater once was (according to the Topo map that Mapper allows you to look at).
"If you go to coordinates: N 40 54' 44" W 72 39' 12", and zoom in, you will eventually see two white dots. The towers them selves are pretty invisible - they are essentially coming straight up into your eye. However, if you look carefully, you will see the shadows of the two - straight lines coming out of thee two white dots.
"They are hard to see, but they are there."
After reading Tom's e-mail and revisiting the maps, I figured out why I did not find the WFTU towers. The coordinates that Tom provided differed from the coordinates provided by Radio-Locator. Using Tom's coordinates, I found the towers immediately (see the Bing Maps screen capture above), while the Radio-Locator coordinates were off just enough for me to miss the towers.
Now that I know that the documented coordinates are not necessarily dead-on, in the future I will make sure to look around the coordinates if the antennas don’t pop out at me as I did to find the CIWW transmitter site, whose coordinates were off by over a half-mile!
By the way, midday yesterday I added a needed Connecticut AM radio station to my log: the very weak S-0 to S-1 WSTC in Stamford transmitting 800 watts 49 miles southwest. Equipment used was the stock radio and antenna in my 2007 Subaru Outback Sport.
Until next time, keep on Surfin’!
Midday Monday, I added my 170th AM radio station to the log: WFTU transmitting 1 kW on 1570 kHz from Riverhead, Long Island, New York, 40 miles to the south. The signal was a steady S-3 during the 10 minutes I monitored the station. Receiving equipment used was the stock radio and antenna in my 2007 Subaru Outback Sport.
Oddly, I can not find a photo of the WFTU transmitter site. Radio-Locator points to 40° 54' 48" N, 72° 39' 16" W, but I don't see any antennas at that location on Google or Bing Maps. Go figure!
Meanwhile, Paul Mulford, KC8YHW, passed along a very cool link from the American Radio History website: online copies in Adobe Acrobat format (.pdf) of radio log publications from 1922 to 1991 including White's Radio Log, which along with the World Radio TV Handbook were my constant companions during my radio listening days in the 1960s.
By the way, even though nobody asked, these days I use an Excel spreadsheet for my LW, AM, and FM loggings.
Until next time, keep on Surfin' and go BoSox!
By Mike Schaffer, KA3JAW
For this specialized piece of equipment, you will not be familiar with the manufacturers' nameplates as they are not your popular ham radio companies such as Alinco, Kenwood, Yaesu, Icom, JRC, MFJ or WinRadio. To date there are three company manufacturers: Ezcap, Compro and Terratec, along with other no brand clones.
These devices have been used in Western Europe to watch terrestrial Digital Video Broadcasting (DVB-T) since 1998. These 2.75" (L) x 1.0" (W) x 0.5" (H) 0.7 ounce dongle (stick) devices connect to your computer via a USB 2.0 port.
They are useless in North America as we use a different standard called Advanced Television System Committee (ATSC) for digital transmission over terrestrial, cable, and satellite networks. However, they can be adapted as Software Defined Radios (SDR) for ham radio for the 6m (50 MHz), 2m (144 MHz), 1.25m (222 MHz), 70 cm (420 MHz), 33 cm (902 MHz), and 23 cm (1240 MHz) on some models.
There are two major chip sets built into the STL-SDR dongle: RF silicone tuner and the DVB-T COFDM (Coded Orthogonal Frequency-Division Multiplexing) demodulator.
Elonics, a global leader in RF technology headquartered in the United Kingdom since 2003, has an E4000 multi-standard CMOS terrestrial RF silicon tuner designed to interface directly to a digital demodulator and contains a fully integrated LNA, programmable RF filter, and RF mixers providing superior real world performance. The front end tuner covers the frequency range from 64 - 1700 MHz. However, reports have confirmed they can be made operable from 50 - 2200 MHz with a 150 MHz gap from 1100-1250 MHz on some models.
The heart of the E4000 is an innovative DigitalTune architecture, which allows the user to adjust the performance of the tuner for optimum linearity or noise figure according to significantly improve reception quality.
The demodulator is a Realtek RTL2832U high-performance DVB-T COFDM that supports a USB 2.0 interface with an 8-MHz bandwidth at an IF (Intermediate Frequency) of 36.125 MHz, low-IF of 4.57 MHz, or Zero-IF output using a 28.8 MHz crystal and includes FM/DAB/DAB+ radio support. Embedded with an advanced ADC (Analog-to-Digital Converter), the RTL2832U features high stability in portable reception.
The state-of-the art tuner features proprietary algorithms including superior channel estimation, co-channel interface rejection, long echo channel reception, and impulse noise cancellation, and provides and ideal solution for a wide range of applications for PC-TV, USB dongle and MiniCard/USB, and embedded system via USB interface.
The SDR/GUI (Software Defined Radio/Graphical User Interface) application software is called SDR# (pronounced as SDR Sharp) and was authored by Youssef Touil in C# programming language. It is being offered as freeware (donation supported) for non-commercial, educational use. This software is a high-performance, fully-featured SDR capable of handling sample rates from kHz level sound cards up to multi-hundred MHz dedicated samplers, thanks to it's multi-core architecture. The application can demodulate NFM, AM, LSB, USB, WFM, DSB and RAW modes.
What makes this SDR fun to use are the two Fast Fourier Transformation (FFT) display modes: Spectrum Analyzer and Waterfall. FFT is a clever algorithm which can be used to transform a signal from the time domain to the frequency domain.
Youssef's website is http://www.sdrsharp.com. Feel free to ask questions on his webpage, SDR# Yahoo! group or #sdrsharp@freenode.
A video tutorial of the installation process by David Savidge, AF5DN, is here:
http://www.youtube.com/watch?v=MFqBj8gV0k4
And here is a video from Andy, M6PNP, performing an RTL-SDR 2-meter band scan: http://www.youtube.com/watch?v=YjqBn-LEx9Y
So where can you purchase this cutting-edge technological breakthrough product? The answer is eBay or similar on-line auction websites. Since the product comes directly from China or Hong Kong, expect to wait two to three weeks for mail delivery using free shipping.
By the way, the dongle also comes with a portable magnetic base telescopic antenna and USB cable.
Bonus: If you get tired of listening to the ham radio bands, you can tune-in to the FM broadcast band from 88 – 108 MHz in the WFM mode.
Minimum System Requirements:
Notes:
Roger Eslick, K4RW, passed along this link to a collection of online impedance calculators brought to you courtesy of Montaro Networks, Inc.
Meanwhile, the latest issue of the Make: Newsletter has a must-read article for any maker out there who is considering funding a project via Kickstarter (or something similar): “Six Things About Kickstarting Your Hardware Idea That Will Drive you Insane” by Marie Staver and Jeremy Fryer-Biggs.
Here is another plug for TAPR’s Digital Communications Conference (DCC) coming up the weekend of September 20-22 in Seattle. It looks like another great DCC and I am sorry I will miss it.
My daughter is into arts and crafts and was an early adapter of Pinterest. She talked about all the arts and crafts stuff on Pinterest, so I assumed that the website leaned in that direction and did not offer much in the way of techy stuff. I learned that my assumption was incorrect when I finally got around to exploring Pinterest.
Pinterest is a pinboard-style photo-sharing website that allows users to create and manage theme-based image collections such as events, interests, and hobbies. Users can browse other pinboards for images, "re-pin" images to their own pinboards, or "like" photos. (Source: Wikipedia)
Go to Pinterest, search on radio, ham radio, amateur radio, AM radio, FM radio, shortwave radio, antenna, QSL, etc. and you will be inundated with hundreds of related images and videos pinned by Pinterest users. Some of the images are unique, some you will recognize, some are off-the-wall, most are worth a look and some are worth exploring further.
So far, I have two Pinterest boards, Radio and Ham Radio, that I am slowly filling with pins and I am following a few other boards of interest. (When you follow another board, new pins on those boards automatically show up at the top of the page after you log in so you don't miss anything.)
Until next time, keep on surfin'!
Sunday afternoon, I added two stations to my AM radio log: WHDD on 1020 kHz in Sharon, Connecticut, and WWRL on 1600 kHz in New York City. The two are numbers 157 and 158 in the log that I started keeping about 18 months ago.
During those 18 months, I have used four different radios with four different external antennas. I added the latest loggings using a Crane CC SW Pocket AM/FM/SW radio and a Terk Advantage indoor AM antenna.
The Terk Advantage can be connected directly to a radio that has external antenna connectors, but may also be inductively coupled to a radio without external antenna connectors. Since the CC SW Pocket has no external antenna connectors, I have been using the inductive coupling option.
Initially, I placed the radio next to the antenna (see first figure). The problem with that configuration was that when I moved the antenna to null out or peak a signal, I then had to move the radio so that it was adjacent to the antenna.
Sometimes the null or peak would change slightly after I repositioned the radio and I would have to tweak the null or peak and reposition the radio again. There had to be a better way.
Since the CC SW Pocket is so small, I tried placing it inside the loop of the antenna (see second figure). It fit perfectly and when I moved the antenna to null or peak a signal, the radio moves with the antenna, thus I usually find the null and peak on the first attempt.
The Advantage is an excellent antenna. It is lightweight and compact with a 9-inch diameter.
It does a great job pulling in signals. Oftentimes, it picks up signals that the radio does not hear with its own internal antenna. Couple the radio with the antenna and suddenly there is a station on frequency that was not detectable sans the antenna.
The dial on the antenna allows you to peak the signal. It is labeled in kilohertz to simplify tuning the peak.
The Advantage also does a fine job of nulling signals. When I logged WWRL, WHNP in East Longmeadow, Massachusetts, was equally as strong on 1600 kHz. Although the two stations were approximately 180 degrees apart at my location, WWRL to my southwest and WHNP to my northeast, I was able to null out WHNP and hear WWRL in the clear.
One more thing: the Terk Advantage is the coolest looking antenna I have ever owned.
Until next time, keep on surfin'.
Reading "Coak and Dagger: More Cuban Spy Broadcasts" in the July issue of Popular Communications, writer Steven Handler mentioned that Cuban spy stations transmit data using "Redundant Digital File Transfer (RDFT), a digital mode developed for amateur radio operators."
I need to get out more because I was not familiar with RDFT. In fact, I had never heard of it.
A little Googling and I discovered that RDFT was the first digital modulation signal format for digital SSTV and was the brain child of Barry Sanderson, KB9VAK. I plead ignorance because SSTV is one of the few ham radio modes I have not tried. (After all, who wants to see my mug? I might get an FCC citation for scaring the kids.)
Chapter 9 of Image Communications on Short Waves also known as the "SSTV Handbook," a freely downloadable e-book by Martin Bruchanov, OK2MNM, covers RDFT.
There is also a YouTube video of a recording of a Cuban numbers station using RDFT on July 24, 2011, on 9063 kHz in the AM mode.
Beyond RDFT, Rick Muething, KN6KB, proffered SCAMP (Sound Card Amateur Message Protocol) at the 2004 Digital Communications Conference (DCC). "SCAMP leverages the work by Barry Sanderson, KB9VAK and employs an ARQ 'wrapper' around Barry's Redundant Digital File Transfer (RDFT) scheme to provide the error-free automatic operation necessary for today's modern digital message systems.
Until next time, keep on surfin'!
We have decided to discontinue the web columns
("Surfin'", Gary Hoffman's "Amateur Amateur" column,
and Sterling Coffey's youth column) at this time,
and to renew the website's focus on news. Tad Cook's
solar report will remain, as it is akin to a weather
report.
Our reader studies have shown that news attracts
and maintains a very high readership, whereas
readership of the web columns is low. In our effort
to give members what they want, we are increasing
our efforts to publish ham radio news. You may
have noticed that the web news crawl has been
particularly active in recent weeks -- a result
of our new initiative.
Thank you for your service to the League.
That’s all she wrote.
I don't know if you read my weekly online column, Surfin' on the ARRL website. If you do read it, then you may have noticed that it has been missing for the last two weeks.
As I wrote here in my previous post, that's because as of June 4, Surfin' has been suspended until further notice as "the focus of the League’s web offerings is being reevaluated."
I have received no "further notice" and I fear the worst.
If you enjoyed reading Surfin' and would like to see its return, please tell ARRL Headquarters (e-mail hq@arrl.org) and more importantly, tell your ARRL Division Director (his/her e-mail address is listed here: http://www.arrl.org/divisions). Thank you!
This week, Surfin’ recalls all the friendly faces at the Dayton Hamvention®.
