Category Archives: Articles

Guest Post: An Unusual Night for CB

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN) for the following guest post:


An Unusual Night for CB

by Mario Filippi (N2HUN)

December 2nd was an unusual night for CB (Citizen’s Band) radio, as the band was open late (0030 GMT) when I turned on the President Washington CB radio just to see who was on. First stop was Channel 19 (27.185 MHz), the trucker’s channel, where the QRM was high, due to the skip from the many truckers on the channel. Earlier in the day this channel was very quiet as was the rest of the band. The fact that Channel 19 was pinning the S meter after dark was a big hint that the band might be open. And it certainly was!

Uniden President Washington AM/SSB Base Station

Being a CB’er from back in the 70’s (call sign KBN-8387), this band was my first serious introduction to two-way radio communication, and after 40+ years it’s still an enjoyable experience to listen in to the local, and sometimes DX chatter. For the most part the CB band mimics 10 meters, basically open during the day (except when sunspot numbers are low) and closed at night. That’s the usual drill, but Mother Nature doesn’t always go by the playbook and sometimes the band is opened at the darnedest times, sometimes even after midnight!

So this evening around 8:30 EST the President Washington CB base station was fired up and CB operators were heard in Maine, Illinois, and as far as Wisconsin, definitely what would be considered out of the ordinary range of CB, which is generally several miles. Now FCC rules still state that it’s illegal to communicate over 155 miles but it’s a non-issue when the band’s open. For the most part, AM is used on most of the channels but you’ll find LSB activity on Channel 36 (27.365 MHz). And when the band gets busy and crowded, you’ll hear LSB QSOs from Channels 36 – 39 (27.365 – 27.395 MHz) as sidebanders spread out among the channels so that they can work each other through the QRM.

To get a better idea of what the CB band “looks” like during a band opening, a spectral scan of the band (26.965 – 27.405 MHz) would be useful. This can be achieved using an SDR dongle, such as the RTL-SDR.com version which is a diminutive broadband receiver with an analog to digital converter and covers from about 26 – 1670 MHz. Used in conjunction with an up-converter (from Nooelec), software such as SDR# (SDR Sharp) and a computer (Smartphone apps are available also) you’ll be able to put up a spectral scan of the band as well as hear what’s happening.

RTL-SDR.com dongle – a small broadband receiver covering all modes

Nooelec’s Ham It Up RF Upconverter expands dongle’s receiving range to the entire HF and MW band

As the old adage goes, “a picture is worth a thousand words” so tonight the SDR dongle, along with SDR# software was fired up to get an idea of how many stations were on during the opening. The antenna used was an S9 43 foot vertical, the same one I use for HF. Using the dongle, it’s an easy feat to visualize the entire CB band on the spectral scan, which is a plot of frequency (X axis) versus signal strength (Y axis). The top half of the screen is the spectral scan and the lower half is the “waterfall” which is a time lapse recording of the spectral scan.

Screenshot of CB Band (wide red stripe) during tonight’s opening.

Normally at this time of night a spectral scan of the CB band would be flat-lining, but as you can see there are plenty of stations conducting QSOs, with the stronger stations having higher peaks and more intense tracings on the waterfall. Seeing the entire CB band visually gives one lots of information such as what channels are active, how many stations are on, what stations might be running higher power (limit is 4 W AM, 12W PEP SSB output), whether outbanders are active or whether DX stations outside the US are partaking of the opening.

Over the years I’ve heard the CB band open beyond midnight and on a winter’s night during a snowstorm. Some openings have lasted for hours. Last year, using the mobile CB, operators from Europe, the Caribbean, and as far away as Australia were heard during my commute to work. At the opposite extreme some days all you’ll hear is ignition noise, hihi. It’s a lot like 10 meters and even a bit like 6 meters; you never know what surprises Mother Nature has in store. Spin the tuning dial over to the CB band and take a listen one of these days.


Thank you so much, Mario!

Only a few weeks ago, I noticed on my SDR’s wideband spectrum display that the 11 meter band was very active.  I started listening around and was absolutely amazed at how organized some of the nets were and how reliable skip was. Signals were blanketing all of the eastern US and even into the west. Sometimes I think there are openings on the 10 meter band, for example, but there are so few users there in comparison, no one notices. The CB frequencies are pretty much always active, when conditions are favorable for DX, everyone instantly notices!

Many might not realize that even their portable shortwave radio can tune the CB frequencies. Thank you again!

Guest Post: The Story And Restoration Of My Hallicrafters SX-42

halllicrafters-sx-42-front-panel

Many thanks to SWLing Post contributor, Arthur Smith, who shares the following guest post:


The Story And Restoration Of My Hallicrafters SX-42

by Arthur Smith

As a junior high student way back in 1978, I had a natural interest in radios. My dad was a ham radio operator, electronics engineer, and designer. We always had cool, exotic radios and electronic gadgetry around the house. He was also in the Korean War, in the US Army Corps of Engineers, with access to a wide variety of equipment. He often told me the story of how he became interested in radio at an early age, and how he saved up for expensive radio gear, with a little help from my grandparents. Back in 1946, Hallicrafters was THE brand to own, and their postwar designs from Raymond Loewy, were catching the eye of many enthusiasts. The SX-42 was being hyped up in Hallicrafters ads as the ultimate radio to own, one that could tune the shortwave and ham bands, and beyond. I don’t know the complete story, but prior to acquiring his SX-42, my dad also purchased an S-38 and S-40. Never satisfied with “good and better”, my father wanted “the best”. All 15 tubes and 50-plus pounds of boatanchor.

Always ambitious and industrious, he mowed lawns, repaired motorcycles, and did odd jobs for neighbors in his suburban Boston neighborhood. He worked smart, and worked hard. And that fall, bought his SX-42.

halllicrafters-sx-42-front2

The radio, we think, was about $279, which would make it the equivalent of almost $3500 in today’s dollars. He heard the start of the Cold War, and the Soviet Union’s Sputnik. And the birth of Rock and Roll on FM! He graduated high school, went away to the Korean War, serving two Tours of Duty. He came back home, and became an electronics engineer. And a licensed ham radio operator.

Moving ahead to 1978, and yours truly had the radio bug, in the worst way. Not as ambitious or as savvy as my father, a classmate, who was also a ham radio operator, told me about a National HRO he had, with some coils, and maybe needing some work. My Dad came home from work, and I just had to tell him about this great opportunity, which of course, would require his financial backing. At this point, the SX-42 and his other two Hallicrafters were seeing “backup” duty, having long since gone solid state in his post. “Hey, I’ve got an idea!” When a Dad says that, a son usually wants to run. Not in this case. “How about we give you my SX-42?!” Gee, twist my arm. I had loved watching those mesmerizing green back lit dials, S meter, and geared tuning knobs. Unfortunately for my classmate, he had to keep his National. Fortunate for me, I had my father’s SX-42!

That radio logged my first 100 countries, including QSL cards from countries and stations no longer in existence. It heard the fall of the Berlin Wall. And, it was at the heart of my school Science Project, which made Science Fair, featuring an experiment on longwire shortwave radio reception.

halllicrafters-sx-42-open

halllicrafters-sx-42-tubes Years later, the focus became family, a child, and a house. The SX-42 and siblings came with me, but this time, in boxes. After having seen a WW2 vintage Hallicrafters S-20R at a consignment shop a couple of summers ago, I thought how cool it might be to have Dad’s radios electronically and cosmetically restored.

The S-38 and S40 were in a box in my damp basement. While intact, they had a considerable amount of rust. Luckily, I was able to find a gentleman with great electronic and mechanical skills. He brought the S38 back to life, working and looking beautiful. And is working still on the S-40. As for the SX-42, that was upstairs in a box in my son’s closet. Dry and somewhat preserved, but with some corrosion on the control panel. And sadly, that iconic lock knob that switches between main tuning and brandspread tuning, had been lost in the move. I had to find someone who could take this project on.

After an extensive search, I found my man. An engineer with his own business, who was moving into retirement, and shutting his business down. He had restored an SX-42 a few years back, with amazing results. I had to lure him out of retirement! Which I did after a few emails back and forth. And, he was within driving distance! First warning was “do not power the radio back up under any circumstance- you’ll fry the wafers on the bandswitch!” I resisted temptation, as I had read online that these were notorious for failure, usually to some original capacitors that leak over the decades.

After 13 months replacing every capacitor, virtually every resistor, and vacuum tube, the iconic radio was coming back to life, in a great way. The transmission and gears in the tuning was re-lubricated. During the restoration process, a date was found stamped on the chassis of October 25th, 1946. Could it be?

img_7367-02-12-16-06-57-1Hallicrafters had advertised in the Oct, 1946 issue of Radio News that “The first hundred are always the hardest to build.” This, coupled with the fact that none of the chassis circuit had been modified, lead my restorer to believe that my radio was one of the first 100 SX-42’s that Hallicrafters had built!

The front panel was stripped and treated, professionally painted and silkscreened. The cabinet and apron bead blasted, repainted, and clear coated. It came back home with me last month. A month after it turned 70.

halllicrafters-sx-42

As you can see here, the radio looks stunning. And, with all the Hallicrafters Service Bulletin mods implemented, sounds and performs better than I remember. Maybe more importantly, we were able to locate a replacement brake lock knob for the tuning shaft, even with the “Lock” decal and arrow showing to rotate it counterclockwise. It just would not have felt complete without that little knob- and, it works!

halllicrafters-sx-42-frontEngaging a set of what essentially are brake pads, you rotate it once to disengage the main tuning and engage the bandspread tuning. Again, and you’re back to main tuning.

halllicrafters-sx-42-ad

This radio will always remain a truly cherished family heirloom, and will be my son’s someday. Complete with the original owner’s manual, and Darth Vader-like R42 Reproducer (speaker).

halllicrafters-sx-42-front-panel

Hopefully to live on for another 70-plus years, and hear more history along the way.

-Arthur Smith Worcester, MA


Wow–!  Thank you so much for sharing your story with us, Arthur. No doubt, your SX-42 will certainly outlive all of us and will hopefully continue to be passed down through your family. What a wonderful story.

Update: Hoax Radio transmissions at Melbourne and Avalon airports

The Melbourne Airport (Source: melbourneairport.com.au)

The Melbourne Airport (Source: melbourneairport.com.au)

Many thanks to SWLing Post contributor, Phil Brennan, who writes:

Just a follow up from last week’s story regarding hoax transmissions on airline frequencies at Melbourne airports. An arrest has been made and, if found guilty, the person may face up to 20 years imprisonment. Heavy stuff. Here’s a link to the Aust Federal Police media release:


Man charged following unauthorised radio transmissions at Victorian airports

This is a joint media release with Airservices Australia and the Australian Communications and Media Authority

The Australian Federal Police (AFP) has charged a 19-year-old Rockbank (Victorian) man with serious offences related to the alleged unlawful interference with air traffic control and endangering the safety of aircraft at two Victorian airports.

The arrest follows an AFP-led investigation with the assistance of Airservices Australia, the Australian Communications and Media Authority (ACMA) and Victoria Police.

Between 5 September 2016 and 3 November 2016, there were 16 separate unauthorised radio transmissions at Melbourne Airport and Avalon Airport causing interference with air traffic control.

On 21 November 2016, the AFP arrested a man and subsequently charged him with:

  • four counts of endangering the safety of aircraft contrary to Section 25(2)(b) of the Crimes (Aviation) Act 1991 (Cth); and
  • one count of interference likely to endanger safety or cause loss or damage contrary to Section 194 of the Radiocommunications Act 1992 (Cth)

The man is scheduled to appear before the Melbourne Magistrates Court this afternoon.

The AFP’s head of Crime Operations, acting Assistant Commissioner Chris Sheehan said this arrest demonstrates how law enforcement takes the safety of the airline industry very seriously.

“The current security measures in place for the airline industry are robust, and the traveling public should be reassured we are treating this matter appropriately,” acting Assistant Commissioner Chris Sheehan said.

“These incidents were thoroughly investigated by the AFP with the technical support of Airservices and the ACMA.

“The offences this 19-year-old man faces carry a maximum penalty of up to 20 years imprisonment.”

“The AFP also acknowledges the close working relationship with Qantas and Virgin Australia Group and the assistance provided particularly during the early stages of the investigation,” he said.

Airservices said there is no current threat to the safety and security of the travelling public as a result of these alleged radio transmissions in Victoria.

“Airservices worked closely with the AFP throughout this investigation to ensure the safety and security of the travelling public,” Airservices Southern Operations Manager Steven Clarke said.

“Airservices has appropriate procedures, processes and systems in place to ensure the safety of aviation operations at Melbourne and Avalon airports, and across the country and for the travelling public,” Mr Clarke said.

The ACMA uses a range of technologies and techniques to investigate and locate the sources of unauthorized or interfering transmissions across the radio frequency spectrum.

The ACMA reminds members of the public that making unauthorised transmissions may constitute a serious offence under the Radiocommunications Act 1992 (Cth).

https://www.afp.gov.au/news-media/media-releases/man-charged-following-unauthorised-radio-transmissions-victorian-airports

Dan takes a critical look at the BBG as government transition commences

View of the Capitol Building from the roof of the Voice of America on 330 Independence Ave., S.W.

View of the Capitol Building from the roof of the Voice of America on 330 Independence Ave., S.W.

SWLing Post readers are likely aware that contributor, Dan Robinson, is the former White House, Congressional and foreign correspondent for the Voice of America.

I’ve just learned that Dan has authored a piece questioning the viability of the BBG as the US presidential transition take place.

Dan’s commentary titled What’s A President-elect To Do . . . With the BBG? appears on the University of Southern California Center on Public Diplomacy site:

http://uscpublicdiplomacy.org/blog/whats-president-elect-dowith-bbg

I encourage you to read his full article and please direct your comments to the original post on the Center on Public Diplomacy website.

Review of the DoxyTronics 8020CA magnetic loop antenna

8020ca-assembled-1

(Image source: DoxyTronics)

Many thanks to SWLing Post contributor, Troy Riedel, who shares the following guest post:


Review: DoxyTronics Portable HF Magnetic Loop 8020CA

-by Troy Riedel

Before I purchased the DoxyTronics 8020CA antenna, I emailed the owner/manufacturer and asked if he felt this antenna would be a good choice with the radios that I own. He promptly and courteously answered my question and I purchased the antenna on September 30th. I received the antenna approximately 6-days after I ordered it.

The DoxyTronics 8020CA magnetic loop antenna

The DoxyTronics 8020CA magnetic loop antenna

I have been evaluating the antenna for 5-6 weeks mostly on my Grundig Satellit 750 and my Grundig G3. I have used other portables but the two aforementioned Grundigs were the radios I used most.

The antenna control box has a ¼-20 hole on the bottom so it can be mounted to a video camera tripod. The assembled antenna weighs 3 lbs. I tried using a light duty DSLR tripod that I own, however that was nowhere near sturdy enough. I had to use a heavier duty tripod (Ravelli AVT) that I use for astronomical purposes. This Ravelli has a weight capacity of 16 lbs and it easily supported the antenna. I’m confident a much smaller and lighter duty tripod than the Ravelli could be used, I simply don’t own anything in-between as my astronomical binoculars and binocular telescopes weigh 5 – 14 lbs.

The 8020CA Antenna consists of a large tuning knob and control box. The control box has switch settings of 3-5 Mhz and 5-15 Mhz. In testing, I found that I could “tune” up to 17.840 MHz.   No batteries are needed to operate.

The antenna worked equally well with all of the “portable” radios that I tested (I am a SWL’er, not a ham).

I can summarize the antenna’s performance as this: it is not a magic elixir that will allow you to capture signals too faint to recognize without the antenna attached, but it definitely enhances the signal and “stabilizes” it to the point where the level of the signal remains relatively constant (less peaks & troughs in signal strength).

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Hopefully you can hear what I have summarized and concluded. I have included a two and one-half minute recording of the following:

Radio: Grundig Satellit 750
Recorder: RadioShack 140-214
Freq: 7.310 MHz
BW: Wide
Broadcaster: Radio Romania International
Date of Recording: 15NOV2016
Time: 2309 – 2313 UTC

Click here to download as an MP3.

00:00 – 00:30: 8020CA Antenna Attached
00:30 – 01:00: Radio’s Whip Antenna
01:00 – 01:30: 8020CA Antenna Attached
01:30 – 02:00: Radio’s Whip Antenna
02:00 – 02:30: This last 30-second segment is with the 8020CA attached, however I am panning the Ravelli tripod 360-degrees in the horizontal. You will hopefully notice that there is a “sweet spot” where the signal and reception is the best of the entire 2:30 recording. I had set-up the antenna and I completed a quick, test recording of Radio Romania. But conditions changed slightly and the best signal during the recoding was approximately 50-60-degrees away from where the best reception was earlier. This is a positive for the antenna: you can pan the tripod head where the antenna sits to null and/or find the best signal.

Note: this is my first shortwave and radio-related review I have ever done. I have done many astronomical reviews – where I have much more experience – so please be kind towards this first attempt.


No worries, Troy! We’re kind and appreciative here–especially since guest posts are all about sharing our experiences and experimentation!

I must say, the DoxyTronics loop is doing a fine job mitigating the local QRM/interference that is easily heard when only the telescopic whip is being used. I’m also impressed that a passive loop this modest in size has so much gain without amplification. 

Thanks, again, Troy for sharing your review! 

Click here to view and/or purchase the DoxyTronics 8020CA magnetic loop antenna.