Category Archives: Articles

Jock gets a good grounding!

Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post:

Getting grounded – at last!

By Jock Elliott, KB2GOM

Readers’ comments are among the best things about writing for the blog. When a reader responds to a post and leaves a comment, it does three things. First, it lets the author know that someone actually read the post. Second, it provides valuable feedback – “I liked it.” “Did you know about this . . .?” “I had a similar experience.” – and so forth. Finally, it provides the author an opportunity to learn something, and that perhaps is the most fun.

A case in point: when I posted this, Andrew (grayhat) said:

“If you want to make an experiment, connect the end-fed to the Satellit high-Z wire input (clamp), then pick a (relatively short) run of insulated wire connect one end of the wire to the high-Z “ground” (clamp) and the other end of that wire to the “gnd” hole in the wall plug

The above being said, I prefer keeping antennas outside and taking care of the feedline, this helps reducing or eliminating noise from indoor appliances like switching PSUs and other things, anyway, if you want, try the above idea and let me know how it works for you”

To which, I responded:

“Thanks for the comments.

Thanks to a tree falling on the powerlines, I now know that the inherent electrical noise in my radio room is basically down to the level of atmospheric noise.

Neverthless, experimenting with a ground is definitely worth trying. A thin wire, sneaked out the window to a ground rod, might do the trick. I’ll report back after I try.”

Andrew (grayhat) came back to me and said:

“I was serious, try the “wall plug ground” I described, it won’t start any “magic smoke” or the like, otherwise, if you can lay out a wire with a length of 5m max, cut to be NON resonant, and connected to a good ground stake, go for it

Then, if you want to discuss this further, just ask Thomas for my e-mail, I agree to share it with you.”

Now, I really appreciated Andrew’s comments, but what I had not told him was that there is just one wall plug in my radio shack; it is really inaccessible, and I am not sure I can get a ground off it. Further, the rest of the power “system” in my shack is a rat’s nest of power bars and extensions, and I have zero confidence that any of them will provide a useful ground.

But – and this is a big but – I did take Andrew’s point: that connecting an actual ground to the ground clip on the back of the Satellit 800 might improve things. Continue reading

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Radio Waves: DRM Part of BBC Story, Antennas and Smith Charts, Shortwave “Hot Debate,” Carrington Event, and “Deep Freeze”

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

DRM Is Part of the BBC World Service Story (Radio World)

The iconic broadcaster has been supportive of the standard for over 20 years

The author is chairman of the DRM Consortium. Her commentaries appear regularly at

Our old friend James Careless studiously ignores DRM once more in his well-researched, but to our minds incomplete article “BBC World Service Turns 90” in the March 30 issue.

As an ex-BBC senior manager, I would like to complete the story now that the hectic NAB Show is over.

Having lived through and experienced at close quarters the decision to reduce the BBC shortwave about 20 years ago, I can confirm that the BBC World Service decision to cut back on its shortwave footprint — especially in North America, where reliable, easy-to-receive daily broadcasts ceased — has generated much listener unhappiness over the years.

In hindsight, the decision was probably right, especially in view of the many rebroadcasting deals with public FM and medium-wave stations in the U.S. (and later other parts of the world like Africa and Europe) that would carry news and programs of interest to the wide public.

But BBC World Service in its long history never underestimated the great advantages of shortwave: wide coverage, excellent audio in some important and populous key BBC markets (like Nigeria) and the anonymity of shortwave, an essential attribute in countries with undemocratic regimes.

BBC World Service still enjoys today about 40 million listeners worldwide nowadays. [Continue reading…]

The Magic of Antennas (Nuts & Volts)

If you really want to know what makes any wireless application work, it is the antenna. Most people working with wireless — radio to those of you who prefer that term — tend to take antennas for granted. It is just something you have to add on to a wireless application at the last minute. Well, boy, do I have news for you. Without a good antenna, radio just doesn’t work too well. In this age of store/online-bought shortwave receivers, scanners, and amateur radio transceivers, your main job in getting your money’s worth out of these high-ticket purchases is to invest a little bit more and put up a really good antenna. In this article, I want to summarize some of the most common types and make you aware of what an antenna really is and how it works.

In every wireless application, there is a transmitter and a receiver. They communicate via free space or what is often called the ether. At the transmitter, a radio signal is developed and then amplified to a specific power level. Then it is connected to an antenna. The antenna is the physical “thing” that converts the voltage from the transmitter into a radio signal. The radio signal is launched from the antenna toward the receiver.

A radio signal is the combination of a magnetic field and an electric field. Recall that a magnetic field is generated any time a current flows in a conductor. It is that invisible force field that can attract metal objects and cause compass needles to move. An electric field is another type of invisible force field that appears between conductors across which a voltage is applied. You have experienced an electric field if you have ever built up a charge by shuffling your feet across a carpet then touching something metal … zaaapp. A charged capacitor encloses an electric field between its plates.

Anyway, a radio wave is just a combination of the electric and magnetic fields at a right angle to one another. We call this an electromagnetic wave. This is what the antenna produces. It translates the voltage of the signal to be transmitted into these fields. The pair of fields are launched into space by the antenna, at which time they propagate at the speed of light through space (300,000,000 meters per second or about 186,000 miles per second). The two fields hang together and in effect, support and regenerate one another along the way. [Continue reading…]

Smith Chart Fundamentals (Nuts & Volts)

The Smith Chart is one of the most useful tools in radio communications, but it is often misunderstood. The purpose of this article is to introduce you to the basics of the Smith Chart. After reading this, you will have a better understanding of impedance matching and VSWR — common parameters in a radio station.

The Smith Chart was invented by Phillip Smith, who was born in Lexington, MA on April 29, 1905. Smith attended Tufts College and was an active amateur radio operator with the callsign 1ANB. In 1928, he joined Bell Labs, where he became involved in the design of antennas for commercial AM broadcasting. Although Smith did a great deal of work with antennas, his expertise and passion focused on transmission lines. He relished the problem of matching the transmission line to the antenna; a component he considered matched the line to space. Continue reading

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“Lies, Spies and Secrets – Hidden History of Cincinnati Radio”

Many thanks to SWLing Post contributor, Lee Hite, who writes:

Following up on Dave Snyder’s WLW post, here is the rest of the story about WLWO.

Click to download: Lies, Spies and Secrets – Hidden History of Cincinnati Radio (PDF in Google Drive)


Lee Hite

What a fascinating read! Thank you for sharing, Lee. 

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International Radio Club’s Reprints collection of 900+ articles

Many thanks to SWLing Post contributor, Nick Hall-Patch, who shares the following announcement:

The International Radio Club’s Reprints collection of 900+ articles about antennas, radio propagation, receivers, accessories, plus items of general interest to MW DXers, continues to grow.   We’ve published an update to the index, at  ,  so that everyone can get access to these latest additions.

We’re also pleased to start offering reprints that did not initially appear in IRCA’s DX Monitor, but are not easily found elsewhere.  For example, we’ve obtained permission from the family of the late prolific author, Dallas Lankford, to organize and republish his out of print articles. 

(if you’ve used the index before, you may need to refresh the browser page to see the latest update, dated December 2021)

Click here to check out the IRCA Index (PDF).

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Guest Post: Calculate Station Distances Using Excel Formulas

Many thanks to SWLing Post contributor, Bob Colegrove, who shares the following guest post:

Calculate Station Distances Using Excel

By Bob Colegrove


On occasion, I’ve wanted to know just how far away a station was from my home.  I’ve never been much of a contester, but I know distance can play a part in the results.  There are a number of Internet cites which let you enter latitude and longitude information and then calculate the distance across the surface of the earth.  These are alright on an occasional basis, but I often wind up getting the data mixed for the two locations, and it is not handy when you want to make several measurements.  Here’s a way to generate the distance from your home to thousands of stations with just a little effort.

Many years ago, armed with my faded knowledge of high school trigonometry, I used Excel to calculate the surface distance between any two points on earth.  I managed to find the spreadsheet (file dated 1998) which has no fewer than 11 steps in the algorithm.  Although it worked, when I came back to it a few months later to make a change, I couldn’t remember my thought process.  There are Internet sites which develop earth surface calculations in highly esoteric terms and heavy-duty math.  But life is short, and I wanted to cut to the chase.  There are, in fact, several formula variations which have somehow managed to distill all this down to a neat single-cell calculation, and they seem to work very well.


The spreadsheet figure below is the simplest form used when you have decimal latitude and longitude data as input.  The convention is to use negative numbers for the Western and Southern Hemispheres.  Home is your reception location and all other locations are compared with that to determine the distances.  If you’re curious, the home location (yellow cells) used in these examples is the monument marking the geographic center of all 50 US states in Belle Fourche, South Dakota.  Google Maps is one easy source to determine the exact latitude and longitude of any point on earth.

To calculate the distance between any two points on earth, copy the formula below directly into a cell, then change the reference cell names as appropriate, and you’re ready to go.

=ACOS(COS(RADIANS(90-$B$5)) * COS(RADIANS(90-B9)) + SIN(RADIANS(90-$B$5)) * SIN(RADIANS(90-B9)) * COS(RADIANS($C$5-C9))) * 3959

$B$5 and $C$5 are the cell references for your home address (yellow in the figure above).  Of course, the dollar signs indicate these data remain fixed in each calculation.  B9 and C9 are corresponding latitude and longitude for the example radio station, WTOP (green).  Change these four cell locations as necessary.  The constant, 3959, at the end of the formula is the average radius of the earth in miles.  Use 6371 if you want kilometers.  The data cells in Columns D and E are populated with the formula and produce the result. These values are dynamic and can be replicated down the columns for the rest of your station location data.

Degrees, Minutes, and Seconds Format

The US FCC on-line database contains latitude and longitude tower locations for medium wave stations in Region 2, North, South, and Central America.  However, coordinates are in degrees, minutes, and seconds format and must be converted to digital format for calculation of distances.  The conversion process can also be done in Excel.

In this case, the inclusion of the coordinate hemispheres, N or S, and E or W is important.  Whereas, the hemispheres in the decimal example were signed + or -, the inclusion of the appropriate letters here is necessary.  Cell L5 reads


and cell Q5 is similar for longitude, except “W” is substituted for “S.”  These formulas are then replicated in columns L and Q for each data item.  Columns R and S contain the distance calculation formulas as described above.  Line 14 is not necessary, but can be used to see if your formulas are correct; that is, the distance from home to home should be zero.

Let Excel Get the Information for You

What follows is for anyone tired of copying cumbersome latitude and longitude data.  Unfortunately, it only works on the current version of Microsoft 365 Excel, and apparently goes off into the big cloud in the sky to instantly download the information.

  1. Enter the town followed by either the US state, Canadian province, or other country name (Column A).
  2. Copy these locations to the next column (Column B).  The cells in Column B will become temporary geography cells.  Note:  As shown above, the data have already been converted to geography format (Step 4).
  3. Make sure you have all the geography cell locations selected (Column B).
  4. On the Data ribbon select Geography.  A map icon will appear at the left of each cell, and the state, province and country will be truncated.
  5. For the first latitude (Cell C7), enter =B7.Latitude; likewise, =B7.Longitude in Cell D7.
  6. The formulas in C7 and D7 can be replicated down your list.
  7. Columns for miles and kilometers (E and F) can be added using the distance formula as described above.

The geography data (Column B) cannot be replicated.  If you want to add data later, you will have to reapply the geography format for the new data.  Or, latitude and longitude can still be inserted manually for any additional entries.  The geography data (Column B) are not needed beyond this point and can be deleted or hidden.

Note:  I logged on to my first mainframe computer in September 1976 and have never ceased to be amazed at what these confounded things can be made to do.  I tried as best I could to trip the system with small, obscure towns in faraway places, as well as duplicate names.  I finally succeeded with a relatively large city, Ulaanbaatar, Mongolia.  To be fair, I tried to get it to accept alternate spellings.  So, if you need that one, you’ll have to enter it manually.

Medium Wave Example

This example is for medium wave DXers in Region 2, the Americas.  It makes use of the FCC AM database at  The database currently contains more than 24,500 entries, many of these are duplicate entries for stations using different daytime and nighttime powers.

  1. Download the database as a pipe-delimited text file.
  2. Import the file into Excel.
  3. Create additional columns to convert the latitude and longitude data from degree-minute-second format to decimal as described above.
  4. Add some rows above and enter your home coordinates in decimal.
  5. Create another column to calculate the distance from home to all the stations, again using the base formula above.
  6. Hide any columns in the FCC database that you don’t need.
  7. Finally, by creating an Excel table from all of the data, except your home location, you can do some on-the-fly filtering.

The example below shows some of the stations near our example home in Belle Fourche, South Dakota.  The Distance column on the right has a filter applied to limit the listing in the table to stations within a 150 mile radius, that is, it only lists potential daytime stations.  You could also use the conditional formatting feature of Excel to highlight the same information in the unfiltered data.

Shortwave Example

The AOKI log,, has listings for all of the recent broadcasting cycles, B21, A21, etc.  The Excel format files are zipped for download, and include the latitude and longitude of each station.  Unfortunately the coordinates are not only in degrees, minutes and seconds, but they are all mashed together in one cell for each listing.  Excel to the rescue again.  Select Text to Columns in the Data Tools portion of the Data ribbon.  This feature will allow you to divide the single column into four columns each for latitude and longitude, that is, degrees, minutes, seconds and hemisphere.  Then you can use the conversion formula to change degrees-minutes-seconds to decimal.  Note that the first three digits used for longitude are minutes (they go up to 180); the remaining numerical columns have two digits each (up to 60 or 90), and the hemisphere columns (alpha) one character each.


Here are a few things affecting accuracy:

  1. The constants 3959 or 6371 used in the formula for miles and kilometers are generally accepted averages for the earth’s radius.  The difference between the equatorial (longer) and polar (shorter) radii is about 13 miles.
  2. If you are using town locations in your data, remember that the actual distance to the tower in that town is likely to be different.  The FCC and AOKI data are assumed to be station tower locations.
  3. Some decimal sources of latitude and longitude data have less resolution, which could lead to a slight error.

You’re on Your Own

You may have noticed the examples shown in the figures all have multiple station locations. My thought in doing this was provide some test for accuracy and secondly to provide a seed for developing the spreadsheet into a more inclusive log of stations. There is likely enough basic Excel knowledge among the folks gathered here, and each person will likely have an individual preference in designing a spreadsheet. Nevertheless, the spreadsheet shown in the figures can be downloaded by clicking this link.

The first sheet shows Figures 1 and 2 from this article; and the second sheet, Figure 3. The link in Cell I2 of the second sheet describes how to use the geography feature of Microsoft 365 Excel. The third sheet is a recent copy of the FCC AM database (Figure 4). To facilitate storage and downloading, only stations from 530 kHz to 600 kHz are included. Numerous unused columns from the FCC AM database have been hidden; so you can still copy the full, pipe-delimited FCC database into Columns A through AH. The FCC database has been converted to an Excel table; the Home location is not part of the table. Try substituting your own location for Home (Cells AI2, latitude and AJ2, longitude) and setting a distance filter from your home in Cell AK4. In the example, the distance filter has been set limiting the list of stations to less than 600 miles from our example in South Dakota. Note also that the Conditional Formatting feature on the Home ribbon has been used to highlight stations less than 100 miles from home.

If you have any interest in developing your own spreadsheet, perhaps you can comment on what you have done, or provide the rest of us with something I have missed. Hopefully, I have provided enough information to get you started.

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Guest Post: Crystal Radios – Construction, Listening, and Contesting

Many thanks to SWLing Post contributor, David Day (N1DAY), for sharing the following guest post:

Crystal Radios – Construction, Listening, and Contesting

By David Day – N1DAY

The date was November 2, 1920 and the world was about to change forever when radio station KDKA out of Pittsburgh PA made its first broadcast of election results from the 1920 presidential election.  For the first time in history people knew who won the election before reading about it the next day in the newspaper.  Radio had arrived!

However, hearing the election results was not as easy as powering up an AM radio receiver because radio electron tubes had only been invented a few years earlier and they were still too expensive for most people to afford in a radio set.  After KDKA’s historic broadcast, large 50,000 watt stations began popping up in all major cities around the world.  Even though a tube-driven radio was not yet commonplace, many people listened to these stations on their crystal radios.  The frenzy around radio in the 1920’s was not unlike the excitement around cell phones and the internet today.  If you didn’t have one, you were simply living in the past.

A family listening to a crystal radio in the 1920’s

Fortunately, in the early 1920’s the crystal radio had been around for a while and it was easy to make or purchase a completed set on a limited budget.  The beauty of the radio was that it was a passive device needing no power source other than the radio station’s broadcast that was received by a good antenna about 50 feet long and 15 or so feet above the ground.  Crystal radios derived their name from use of galena crystals as detectors. Continue reading

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Guest Post: Following the Ethiopian war over shortwave radio

Many thanks to SWLing Post contributor and political cartoonist, Carlos Latuff, who shares the following guest post:

Carlos Latuff at Catacumba Park in Rio de Janeiro, monitoring Ethiopian broadcasts.


by Carlos Latuff, special for The SWLing Post

We just entered 2022 and the civil war in Ethiopia has already completed 1 year. On the one hand we have the  Tigray People’s Liberation Front (TPLF) guerrillas from northern Ethiopia and its allies, and on the other hand we have the armed forces of Ethiopian government and its allies. The dead are piling up, accusations of war crimes from both sides, local and international political interests at stake, and no perspective for a peaceful solution. Without going into the reasons for this new war in Ethiopian territory, I’d like to focus on the use of radio waves by both parties of this conflict.

I monitored shortwave broadcasts from Ethiopia and to Ethiopia between October 21, 2021 and January 4, 2022. The receivers were Tecsun PL-606 and XHDATA D-808, using both the telescopic antenna and a long wire. In all cases, listening was carried out in Brazilian cities.

Carlos at Catacumba Park monitoring and recording clandestine Ethiopian broadcasts.

The monitored stations were: Continue reading

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