Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. The second article will focus on construction notes. The third and final article will essentially be a Q&A about the SULA antenna. All articles will eventually link to each other once published.
This wideband unidirectional antenna is an outstanding and innovative development for the portable DXer. I love the fact that it came to fruition via a collaboration between Grayhat and 13dka: two amazing gents and radio ambassadors on our SWLing.net discussion board and here on the SWLing Post. So many thanks to both of them!
Please enjoy and share SULA Part 1:
Introducing the Small Unidirectional Loop Antenna (SULA) 1-30MHz
A small and simple, unidirectional and DX-capable loop “beam” for SWLs!
In early June, Andrew (grayhat), SWLing Post‘s resident antenna wizard suggested a variation of the “cardioid loop” on the SWLing Post message board: The original “cardioid loop” is a small loop receiving antenna deriving its name from a cardioid shaped (unidirectional) radiation footprint. The design is strikingly simple but it has a few downsides: It relies on a custom preamp, it needs a ground rod to work and it is unidirectional only up to 8 MHz.
Andrew’s version had the components all shuffled around and it did not only lose the ground rod, it also promised a nice cardioid pattern over the entire shortwave, from a small, diamond shaped loop. Wait…what? It can be made using parts available on Amazon and your DIY store:
You need some 3m wire and PVC tubes to create a support structure to hold the wire, a 530 Ohm resistor and a 9:1 balun like the popular “NooElec One Nine”. Since it’s a “lossy” design, adding a generic LNA like the NooElec “LANA HF” would help getting most out of it. When you put that all together you have what sounds like an old shortwave listener’s dream: a small, portable, tangible, and completely practical allband shortwave reception beam antenna with some more convenient properties on top, for example, it is a bit afraid of heights.
That sounded both interesting and plain crazy, but the .nec files Andrew posted were clearly saying that this antenna is a thing now. Unfortunately Andrew suffered a little injury that kept him from making one of those right away, I on the other hand had almost all the needed parts in a drawer so I ended up making a prototype and putting it through some of its paces, with Andrew changing the design and me changing the actual antenna accordingly, then mounting it upside down. Let me show you around:
Small, diamond shaped wire loop (with 76cm/29.92″ sides), needing as little space as most other small loops.
Unidirectional with a ~160° wide “beam” and one pronounced minimum with a front/back-ratio of typically 20dB over the entire reception range 1-30MHz.
Moderate height requirements: It works best up to 3m/10′ above ground, where it gives you…
…a main lobe with a convenient flat takeoff angle for DX
Antenna is comparatively insensitive to ground quality/conductivity.
Wideband design, works best on shortwave and is pretty good up to 70cm.
A functional small beam antenna for shortwave reception that’s just as small and possibly even more lightweight (prototype:~250g/9oz) than your regular SML, that can be easily made out of easy to obtain parts and easily carried around for mobile/portable DXing and due to its cardioid shaped directional pattern also for direction finding, a “tactical” antenna that’s also doing DX? Unlike conventional, Yagi-Uda or wire beams it can achieve a low takeoff angle at only 3m/10ft height or less, the front/back ratio is typically better than that of a 3-element Yagi, with a particularly useful horizontal pattern shape. That it’s rather indifferent to soil quality could mean that more people get to reproduce the good results and being a real wideband antenna is making the SULA an interesting companion for multiband radios and SDRs. Really? A miracle antenna? Is it that time of year again? If I had a dollar for every….
Many thanks to SWLing Post contributor, Paul Walker, who notes that he has only a few details about what appears to be a last minute DX test of WBOB in Jacksonville, Florida.
According to Paul’s source, WBOB on 600 kHz will be running 50 kilowatts from midnight to 3:00 AM local (04:00-07:00 UTC) on Saturday, May 14, 2022. Paul’s source noted the test will take place Friday and possibly Saturday nights, but technically these are early Saturday and Sunday times.
We’ve no other details, but Paul wanted to share what info he has. Thanks, Paul!
This is the summary of 3 days of testing of my Icom IC-705 just purchased and immediately taken to Ponza Island, my hometown, for a full immersion DXpedition only listening to amateur radio bands especially on 20 m.
I left Formia on the ship that went to Ponza and it was not a good start given the adverse sea weather conditions. After 3 hours of crossing in the rain and the strong sirocco wind, I arrived on the island at my father’s house.
In the early afternoon in the rain, I hoisted a 20 meter row on the “sloper” type roof not so high from the ground and connected directly to the Icom 705 without any counterweight given the place without electrical noise.
The position of my father’s house is open from West to North but totally covered to the South by a hill of 200 meters …
In this video you can see all of this:
During the first night, 20 meters was full of signals especially from the USA; it was, in fact, what I had hoped for given the position open to the West.
Really good overseas signals despite bad weather … below is a series of mixes of North American stations: Continue reading →
Many thanks to SWLing Post contributor, Adrian Korol, who shares the following announcement from LRA 36:This year the radio team is all female–the host, producer and technicians are all women: Romina Zabalza, Mariela Churquina, Claudia Albarracín, and María Eugenia Rodríguez.
LRA 36 Radio Nacional Arcangel San Gabriel, Base Conjunta Esperanza (Antarctic) Season 2022.
FIRST 2022 TRANSMISSION:
SATURDAY MAY 7, 2022 AT 15:00 UTC ON 15.476 KHZ USB
Many thanks to SWLing Post contributor Loyd Van Horn at DX Central who writes:
Wanted to share this with you…..our final DX Central Live stream for season 2 will coincide with the upcoming WCGA-GA DX Test coming Saturday night/Sunday morning. You should have a GREAT shot at hearing this one….would love to have you join us for the livestream, too, if you can make it!
The link to the release with all of the details can be found below….
FOR IMMEDIATE RELEASE
Apr 28, 2022
The Courtesy Program Committee (CPC) of the National Radio Club (NRC) and the International Radio Club of America (IRCA) is pleased to announce a special DX Test for distant listeners for WCGA on 1100 kHz in Woodbine, GA. The test is scheduled for 5/1/2022 at 12:00:00 AM Eastern Time (0400 UTC Sunday, May 1st). This test is scheduled to run for 2 hours.
For WCGA, Wesley Cox, will be performing regular maintenance of the station’s audio chain and transmitter during the test. Listeners will hear: Morse Code IDs at 10 WPM at 800 Hz, Morse Code IDs at 20 WPM at 1000 Hz, Tone Sweeps, Long duration tones at 1 kHz, Off-hook Telephone Sounds, Voice IDs and more.
WCGA will be operating on a full daytime power of 10,000 watts during the test on their daytime antenna pattern. This should aid DXers across the country and indeed the world in being able to receive this test!
RECEPTION REPORTS & QSL REQUESTS
WCGA is actively soliciting reports from DX’ers on their signal. They’re interested in hearing about frequency stability, audio quality, and overall performance. The station will accept both hard copy reports via USPS mail and email reports. They would love to receive audio recordings in either .WAV or.MP3 and videos in .MP4 video.
Physical QSL card senders will receive a physical QSL. Email QSLs will receive email QSL.
Best audio narrative recording and received via email in MP3 or MP4 about themselves and their passion for radio that includes their reception of WCGA and the who, what, when, where, why and how of that event taking place will receive a special prize from the station. DX’ers who submit recordings must grant permission to broadcast their recordings. The decision of WCGA staff on the winner is final.
The IRCA/NRC CPC would like to thank the owners of WCGA, Wesley Cox, and Hall of Fame DXer, Jim Renfrew, for helping to arrange the test.
Good luck to all DXers!
About the CPC
The Courtesy Program Committee (CPC) is a cross-functional group comprised of members of both the National Radio Club (NRC) and International Radio Club of America (IRCA) for the purpose of coordinating and arranging DX Tests with AM radio stations. These DX tests both allow radio stations to conduct valuable equipment tests on their transmitter and audio chain as well as enable DX hobbyists to receive the testing station from greater distances than would normally be possible. The CPC membership consists of: Chairman Les Rayburn, Paul Walker, George Santulli, Joe Miller and Loyd Van Horn.
For radio stations interested in coordinating a DX test with the CPC, please visit the following Web site for more information:
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)
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.
$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.
Enter the town followed by either the US state, Canadian province, or other country name (Column A).
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).
Make sure you have all the geography cell locations selected (Column B).
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.
For the first latitude (Cell C7), enter =B7.Latitude; likewise, =B7.Longitude in Cell D7.
The formulas in C7 and D7 can be replicated down your list.
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 https://www.fcc.gov/media/radio/am-query. The database currently contains more than 24,500 entries, many of these are duplicate entries for stations using different daytime and nighttime powers.
Download the database as a pipe-delimited text file.
Import the file into Excel.
Create additional columns to convert the latitude and longitude data from degree-minute-second format to decimal as described above.
Add some rows above and enter your home coordinates in decimal.
Create another column to calculate the distance from home to all the stations, again using the base formula above.
Hide any columns in the FCC database that you don’t need.
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.
The AOKI log, http://www1.s2.starcat.ne.jp/ndxc/, 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 DataTools 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:
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.
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.
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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