By Don Moore
Don’s DX touring tales may be present in his e-book Tales of a Vagabond DXer.
I’ve been an actual jack-of-all-trades in my over 5 many years of DXing. I started with SWBC (shortwave broadcast) however quickly branched out to medium wave and voice utility. Later I added longwave beacons and extra not too long ago I’ve gotten into digital utility stations. My aim has at all times been to log plenty of totally different stations from plenty of totally different locations. And the rarer they’re, the higher.
For SWBC and medium wave stations, in addition to scheduled utility broadcasts reminiscent of marine and aeronautical climate stories, the DXing course of is easy. You tune to a frequency at a time when a station is scheduled to be on the air. It’s both there or it’s not there. If it’s not there then perhaps propagation isn’t proper or perhaps your antenna/receiver setup isn’t the perfect for that frequency band or the station’s energy stage. You tune away to seek out one thing else with plans to strive once more one other day.
However it’s not at all times that simple. Most utility stations should not have fastened schedules and solely come on as wanted. One of the best instance of that’s two-way marine, aeronautical, and navy voice communications.
In jap North America, tune to 8906 kHz anytime from late afternoon till morning and set your receiver to USB mode. You’ll in all probability hear empty static at first nevertheless it’s unlikely that greater than ten or fifteen minutes will move earlier than you’ve heard some aeronautical visitors. The frequency is assigned for communication on the North Atlantic and is closely utilized by plane speaking with New York Radio, Gander Radio (Newfoundland, Canada), and Shanwick Radio (Shannon, Eire). For those who maintain listening, the frequency will in all probability be occupied round 25% of the time. Wherever you’re on this planet, there are a number of closely used air frequencies like 8906 kHz and listening to them may be fascinating. However I wish to log greater than just some simply heard stations.
Sticking to aeronautical DX, there are lots of assigned frequencies for various areas and air routes around the globe. However propagation to these distant areas is unpredictable and less-used routes have fewer flights. Fewer flights imply much less radio communication and extra empty static. Probably the most fascinating frequencies could solely see visitors a number of instances every week.
Listening to the rarest voice utility DX requires listening to plenty of empty static simply to get a short DX catch. For years my course of was easy. I might set my receiver to an fascinating frequency and depart the tape recorder working whereas I sat close by listening and doing one thing productive. I bought some superb DX through the years that means. However I don’t wish to take into consideration what number of lengthy hours of empty static I listened to with the intention to get that DX.
SDRs supplied some enchancment. As a substitute of audibly monitoring a particular frequency I may now make a spectrum recording that included a band of curiosity, say the 8815 to 9040 aeronautical band. Throughout playback I may visually monitor the SDR waterfall for fascinating alerts. That works. However watching an SDR waterfall scroll by for 3 or 4 hours will get tedious rapidly.
(Once I consult with SDRs, I imply ones consisting of a small field that’s related to and managed from a pc utilizing a software program program. None of this is applicable to fashions such because the Malachite line or the Icom IC-R8600, which use SDR expertise inside however principally operate as a standard receiver.)
That higher means is, I believe, one of the crucial thrilling DX instruments on the market – the Knowledge File Analyzer in the SDR-Console program. Since I realized about it a number of years in the past, the Analyzer has gotten me all types of catches that I in all probability wouldn’t have gotten in any other case. Let’s begin with an summary after which dig into the how-to.
SDR-Console is among the better-known SDR packages and it really works nicely with a lot of the frequent SDR radios available on the market, together with the Airspy, Elad, Perseus, and SDR-Play fashions. Right here’s what the principle window appears to be like like:
The Knowledge File Analyzer is a second window that produces a scrollable waterfall show for your entire size of an SDR spectrum recording. The show is just like an ordinary waterfall with frequencies alongside the underside and instances alongside the facet. Nonetheless, there may be additionally a scroll bar on the precise facet for looking by way of your entire size of the recording. As a substitute of watching a four-hour spectrum recording slowly roll by in actual time, I can scroll by way of the window in search of DX.
And that is what makes the Knowledge Analyzer actually helpful. Once I spot an fascinating sign, I click on on it and that causes the principle window to start out taking part in at the moment and frequency. Now going by way of a four-hour spectrum recording takes from a couple of minutes to round half an hour, relying on how a lot DX I discover.
Right here’s a closeup of a part of that very same display of spectrum recording made on 24 October 2024 at a DXpedition in western Pennsylvania, USA.
“A” marks a brief alternate between an plane and Ndjamena Radio in Chad on 8894 kHz. “B” is Niamey Radio in Niger on 8903 kHz. “C” is Gander Radio on 8891 kHz. Simply to the left of that may be a string of digital alerts. “D” is New York Radio on 8918 kHz. Once more, there’s a string of digital alerts simply to the left. Lastly, “E” is communication from Dakar Radio in Senegal and Sal Radio within the Cape Verde Islands on 8861 kHz. I caught 4 African aero stations in simply four-and-a-half minutes. I may additionally present you lengthy stretches of time when there was nothing fascinating coming in. With the Knowledge File Analyzer I used to be capable of visually discover and concentrate on the DX and never waste my time with the empty static.
Right here’s one other picture taken on the identical DXpedition. Discover the three transmissions between 8820 to 8845 that appear to be mirroring one different.
That turned out to be Flightwatch Brisbane, the Australian regional aeronautical community. It makes use of a number of transmitter websites on 8822, 8831, and 8843 kHz to cowl your entire nation. I had by no means logged it earlier than and I doubt I might have discovered it if DXing within the conventional method.
Right here I’m going to imagine that you have already got SDR-Console put in and know the fundamentals of easy methods to use it, together with making spectrum recordings. (If not, see the hyperlinks on the finish.) This text was written utilizing model 3.4 of SDR-Console. Among the functionalities described aren’t in earlier variations, so improve in case you are not updated. And I ought to level out that whereas you are able to do this on a single monitor, it really works extra easily when you’ve got a twin monitor setup and may put every window on a special display.
The Knowledge File Analyzer doesn’t seem within the menu by default, so step one is so as to add it. Open SDR-Console. Choose “View” on the highest menu bar. On the precise facet, click on on the three dots labeled “Choose” to open this system choices field. Allow the Analyzer, click on OK, and look forward to this system to restart.
After SDR-Console restarts choose the “View” menu once more. You need to see the Knowledge File Analyzer possibility on the far proper.
Now we’d like some recordsdata to research. To start out, I like to recommend recording a slender spectrum, reminiscent of 384 kHz large. Most SDRs provide that as an possibility. Choose a band and time the place you possibly can anticipate finding some alerts. For marine communications, 8200 kHz is an effective heart frequency or use 8900 kHz for aeronautical stations. In most components of the world these ranges ought to have some motion from late afternoon till the following morning. With SDR-Console you possibly can both report to 1 massive file or a sequence of 1 GB recordsdata. I desire utilizing the 16-bit 1 GB possibility as I believe actually massive recordsdata decelerate the Knowledge Analyzer. Report for not less than an hour or two.
When your recording is completed, open the Analyzer window. Within the prime left nook, click on on “New” to open the file choice window and browse to pick out the file. Clicking the Play button will open the Choices window. For now don’t choose Allow within the Heart field and below Replace Fee choose 4 traces per second. We’ll focus on these settings under.
Click on OK. Give the Analyzer a couple of minutes to run. The full measurement of the recordsdata and your pc’s velocity and reminiscence will decide how rapidly the Analyzer works by way of a set of recordsdata. I wouldn’t suggest working it within the background whereas streaming an HD video. However doing routine duties like checking e-mail or looking the online shouldn’t trigger an issue.
As soon as the Analyzer has completed you possibly can click on Save within the prime menu bar and save the analyzed knowledge to an XML file. That’s solely essential in the event you count on to shut the Analyzer and are available again to the file later. For those who do save XML recordsdata you should definitely periodically delete those you now not want as they are often very massive.
Let’s try a few of the gadgets on the menu bar throughout the highest of the Analyzer window. First, your waterfall might not be as simple to learn as my examples above. Click on on the Distinction possibility on the menu bar to deliver up the Distinction Slider management and make any essential changes. Click on on the Distinction possibility once more to shut the slider. Slightly below the Distinction possibility is a button for UTC. Choose that to have instances displayed in UTC as an alternative of no matter native time zone your laptop computer is about to. Additional to the precise is the beginning button. Click on on that to start out playback in the principle SDR-Console window. Simply to the precise of that’s the Snap setting which determines the frequency precision while you click on on a sign. I discover 1 kHz to be finest. Lastly, within the heart of the menu-bar, activate the Crosshairs possibility.
You’re now able to DX. Begin on the backside of the show, the place the time begins, and work your means up. While you discover an fascinating sign, hover the mouse cursor over it to point out the time and frequency and click on on it to open the principle window at the moment and frequency. On this instance, the frequency is clearly the aeronautical frequency of 11279 kHz. I simply want the crosshairs show to point out one thing inside +/- 500 Hz and the Snap setting will spherical it to 11279.0 when the sign opens in the principle window.
Hopefully the primary time you utilize the Knowledge File Analyzer you’ll be overwhelmed with all the knowledge in entrance of you. That’s good – you may have a number of alerts in your recording. Over time you’ll be taught what’s routine and what’s uncommon and in addition easy methods to visually distinguish between voice and digital alerts. Then you possibly can concentrate on what’s fascinating to you.
Now let’s transfer on to some finer factors of utilizing the Analyzer.
So now you may have a 384 kHz large spectrum show in your Analyzer window. When you’ve got a big monitor that appears nice. However in the event you’re taking a look at a 13-inch laptop computer show you is perhaps feeling a bit eyestrain. One of many disadvantages of the Analyzer is that it shows your entire width of the evaluation and there’s no option to zoom in. The one means round that’s to run the evaluation on a slender vary of frequencies as an alternative of on your entire spectrum width.
To know what I imply, examine the next graphic. The photographs are equally sized screenshots taken on my 15.6-inch Arzopa journey monitor. Within the prime I ran an evaluation of your entire width of a 1536 kHz large recording made with my Elad FDM-S2. On the backside I ran an evaluation of a 250 kHz large portion centered on 8230 kHz for the marine voice band in the identical recordsdata. Not solely is it simpler to tell apart the person alerts on the underside, however some weaker alerts under aren’t even seen on the prime. After all, to DX the remainder of the recorded spectrum I must run additional evaluation on the narrower width.
To manage the evaluation width, we have to return to the Settings window when working the unique evaluation. Click on Allow within the Heart field, enter a frequency inside the limits of the file, after which choose a bandwidth.
This system will warn you in the event you enter a middle frequency that will prolong the evaluation exterior the bounds of the file.
Which evaluation width works finest for you’ll rely upon the dimensions and backbone of your monitor and the way good your eyesight is. Once I had a 21-inch monitor I may go as much as 400 kHz earlier than I began having bother seeing weaker alerts. On my smaller Arzopa journey monitor, 300 kHz large appears to be the highest. With recordings made at wider bandwidths you simply should run a number of analyses. To research a 768 kHz large file on the Arzopa I make two runs at 250 kHz large and one at 300 kHz large, with a bit little bit of overlap.
The opposite possibility within the evaluation settings window that impacts readability is Line Per Second. Within the above picture I used a setting of 4. The following image reveals the distinction between 4 traces per second on the left and one line per second on the precise. The fitting facet reveals about 13 minutes versus solely three-and-a-half minutes on the left. Nonetheless, some voice utility messages are very quick. A five-second message utilizing twenty traces on the left facet could be a lot simpler to identify than if utilizing simply 5 traces on the precise.
Invoice Nollman factors out one other factor to contemplate with Strains/Second. Look again a number of photos to the Basic Settings window the place I set the Replace Fee to 4 Strains/Second. Slightly below that it reveals that it will produce 43,204 complete traces. Invoice says that, within the present launch, if this worth is over 60,000 then the time show on the analyzer will present gaps. His workaround is to make use of the Begin and End Time possibility on the prime of Basic Settings to research the recordsdata in timed sections not exceeding 60,000 complete traces. Simply remember that when utilizing the workaround the primary timed part works as anticipated however the subsequent could not work appropriately for level and click on tuning.
Step one in working the Analyzer is to click on New to open the file choice window. That window reveals a number of helpful info and you may reorder the columns, as I’ve, to raised see that. This subsequent picture reveals principally MW recordsdata I recorded in Rafina, Greece. First there may be the beginning date/time, then file identify (or identify of the primary file within the chain), and subsequent the overall period of the spectrum recording. After that there’s the middle frequency, bandwidth, and the overall file measurement and variety of recordsdata within the spectrum recording. Below Format right here, I’ve each recordsdata made in SDR-Console and made within the Winrad format with HDSDR. I’ve additionally used Elad recordsdata within the Analyzer and I consider it really works with most traditional SDR file codecs.
Relying on the SDR program used, lengthy spectrum recordings produce a series of recordsdata designated file_00, file_01, file_02, and many others. When the file choice window is open, the Analyzer lists solely the preliminary file_00 recordsdata. And that’s high-quality as you doubtless wish to analyze your entire chain. Nonetheless, in the event you unintentionally delete the preliminary file (as I as soon as did) then every subsequent file is listed individually and the Analyzer received’t analyze your entire chain in a single single go. The work round is to rename the file_01 file to file_00. That’s it. The Analyzer doesn’t care that there isn’t a file_01 file. However it has to see that file_00 file to research a whole chain of recordsdata.
This lacking preliminary file downside could solely be a difficulty with recordings made utilizing SDR-Console. Brett Saylor had no such downside when testing utilizing Perseus recordings made with the native Perseus program nor with Mestor. I counsel testing this out with no matter recording program you utilize. Or higher but, don’t unintentionally delete that preliminary file!
As with all new software program, it takes a while to learn to finest use the Analyzer. My methodology is to start out originally (backside) and work my means up. If I discover an fascinating sign however can’t establish it I comply with the frequency additional up the spectrum to see if the station comes again later when circumstances could have improved. How lengthy does it take me to undergo a three-hour set of recordsdata 250 kHz large? It relies on what number of fascinating alerts there are. Three or 4 minutes will do it if reception was poor. I’d say twenty minutes is regular. Even the perfect ones don’t take greater than thirty to forty minutes. Voice utility transmissions are usually quick.
Whereas I primarily use this for utility DXing, I’ve additionally discovered some makes use of for medium wave DX. I’ll clarify these later in one other article.
So if you wish to hear some critical voice utility DX – and also you don’t wish to spend hours listening to empty static to get it – give the Knowledge Analyzer a strive. You received’t be upset.
Thanks to Ralph Brandi, Invoice Nollman, and Brett Saylor for reviewing this text and making helpful solutions.
