Category Archives: Uncategorized

From the Isle of Music Adds 3rd Listening Option; Program Dec 6, 9





On December 6 (December 5 local date in the Americas), our special guest will be the delightful Cuban violinist Tanmy López Moreno, who in addition to performing with Interactivo has her own project. We will feature music from her two albums. We will also play selections from 4/1, an award-winning album by Cuban concert pianist Fidel Leal. And to add a little something extra, some vintage Cuban Rock from Los Gafas.

Three options for listening on shortwave:
WBCQ, 7490 KHz, Tuesdays 0100-0200 UTC (8pm-9pm EDT Mondays in the Americas)
Channel 292, 6070 KHz, Tuesdays 1900-2000 UTC (2000-2100 CET) and (NEW) Fridays 1100-1200 UTC (1200-1300 CET)
See the NOTES section of our Facebook page for instructions for listening online if you are out of range or don’t have a shortwave radio.

Portable shortwave spectrum capture for the urban city dweller

A guide by London Shortwave

Portable Spectrum Capture Set-up

Capturing the shortwave spectrum out in the field.

Radio interference is a major problem in big cities when it comes to indoor shortwave reception. One effective solution I have found is to head for the local park and engage in scanning the bands there. However, since my time for making such outdoor trips is limited, I would always feel like I am missing out on a lot of radio action by monitoring a single frequency, which is all you can do with a standard shortwave radio. There are so many signals out there — which one should I go for? This inspired me to put together a lightweight, portable set-up that would let me capture large chunks of the shortwave radio spectrum out in the field, which I could later explore in detail. After two years of experimenting with various Software Defined Radio (SDR) technologies I am pleased to report that I finally have a solution that works well for this purpose.

A good SDR can give the user access to large portions of the radio spectrum via a graphical user interface. The user can then either process a specified part of it in realtime or record the chosen spectrum window in its entirety onto disk and analyse it later with the supplied software. Here is a short video showing the playback of one of such spectrum captures I made in a London park in September 2016. Note the final part where I zoom out to show the entire recorded frequency range (covering two broadcast bands with one ham band in the middle!):

When I got home from the park, I was able to replay that part of the spectrum capture many times over while scanning the frequency space, which is how I was able to identify a weak signal from a very distant ham radio operator that I might have otherwise missed.

Below is the list of the components I have used to put together my “portable spectrum capture lab”.


Component List


1. Toshiba Encore 8″ Tablet (Windows 8), 2014 Model ($169)

I bought this tablet in July 2014, based on the following criteria: the device had to have a reasonably powerful Intel processor, running the Windows 8 operating system. I believe that there are currently models on the market that are at least as powerful and are substantially cheaper (<$100).

2. On The Go USB Adapter ($15)

3. AirSpy R2 SDR ($169)

Owing to its unique hardware design, the AirSpy SDR can monitor large parts of the radio spectrum (up to 10 MHz in bandwidth) while offering a high dynamic range and robustness to overloading, with almost no mixing/imaging products.

4. SpyVerter HF UpConverter ($49)

This additional device enables AirSpy to cover the shortwave bands (in fact, the entire frequency range between 0 khz and 30 MHz) and must be connected in-line between the AirSpy’s front end and the antenna feed line, as follows:

AirSpy / SpyVerter

Connection cables

Below is a small collection of cable accessories to connect the antenna to AirSpy/SpyVerter:

5. 10cm SMA Male to SMA Male Straight RF Coaxial Jumper Pigtail ($2)

6. BNC Male Plug to SMA Female Jack Adapter ($2)

7. BNC Female Coupler ($5)

8. 3m long BNC cable ($15)

Matched dipole antenna

Antenna Schematic

I use a three-terminal matched balun connected two 6 metre copper wires via its antenna terminals as a dipole antenna, and connect it to the SDR via the feed line terminal with the 3m BNC cable listed above. The balun (Wellbrook UMB130) is engineered in a way that prevents the radio noise current from the tablet (usually a significant source of interference) flowing into the receiving part of the antenna.

Dipole Antenna

9. Wellbrook UMB 130 balun ($60)

10. 2 x 6m Copper Wire ($16)


11. Fight Case ($35)

This foam-filled flight case comfortably houses all of the components. The parts 1 to 7 can remain assembled together, reducing the deployment time in the field.

12. Samsung 64G Ultra-High-Speed MicroSD Card ($19)

Samsung MicroSD Card

I use this fast MicroSD card as the destination for my outdoor SDR recordings. The high transfer speed is critical – using slower MicroSD cards will result in large portions of the spectrum being dropped from the recordings. 64 Gigabytes can accommodate roughly one hour of spectrum data at 3 MHz bandwidth.

13. FAVI Bluetooth keyboard with trackpad ($37)

FAVI Bluetooth Keyboard

Windows tablets suffer from one major drawback: the touchscreen interface is usually inadequate for software that was designed for traditional computers with mice. A portable Bluetooth keyboard with a built-in trackpad solves this problem.

14. Bluetooth Wireless Audio Transmitter & Receiver ($17)

Bluetooth Transmitter / Receiver

This small gadget turned out to be a very important part of the entire project. The Toshiba tablet has a rather unusual interference quirk that initially caused me hours of frustration. It turns out that significant amounts of radio noise are injected into the SDR when the tablet’s external speakers are active. One way to fix this is to plug a pair of headphones into the tablet’s line out jack, but this forces the listener to be glued to the device. The alternative is to pair the tablet with a Bluetooth audio receiving unit, such as the one listed above. It is worth noting that my other Windows tablet — a Dell Venue 8 — also suffers from this strange artefact.

Total cost: $610

Internal layout of the flight case

Flight Case Internal Layout

You’ll see that I have stacked the SpyVerter enclosure on top of the AirSpy one. As the latter can get very hot, it is essential to leave a sufficiently large gap in the foam for ventilation. It’s also worth leaving a small gap next to the tablet’s power button to prevent Windows from accidentally going into standby mode.

Software configuration

The best software to use with the AirSpy/SpyVerter combination is SDR#. It offers an impressive collection of features that many software packages and conventional radios don’t have, such as advanced noise reduction and synchronous detection with passband tuning. The following adjustments are required to make recording the spectrum a seamless experience:

Install the Baseband Recorder and File Player plugins

Baseband Recorder: this plugin enables efficient recording of very large spectrum (or “baseband”) files. Download and decompress the plugin zip file. Copy the .dll files into the directory with the SDRSharp.exe executable. Open the MagicLine.txt file and copy the first line of text into Plugins.xml file, just before the “</sharpPlugins>” line.

File Player: this plugin enables the playback of recordings made with the Baseband Recorder plugin. Download and decompress the plugin zip file. Copy the .dll files into the directory with the SDRSharp.exe executable. Open the MagicLine.txt file and copy the first line of text into FrontEnds.xml file, just before the “</frontendPlugins>” line.

Configure Baseband Recorder

Open SDRSharp.exe and check that the program reports no errors when it loads.

Baseband Recorder Plugin

Baseband Recorder configuration

In the plugin pane on the left, expand the Baseband Recorder tab and click “Configure”. Change the File Format to WAV RF64 and make sure that the File length limit check box is not ticked. Click “Folder select” and choose the MicroSD card as the destination directory for the recordings.

Adjust AirSpy settings

Disclaimer: in this section I describe how I capture the maximum spectrum bandwidth that my tablet’s CPU can handle. It involves operating SDR# in “debug mode” and exposes some internal functionality of AirSpy, which, if used incorrectly, can damage the radio. If you choose to copy my approach, please understand that you are doing so at your own risk and follow my instructions carefully to avoid voiding your AirSpy warranty.

Open SDRSharp.exe.Config file in Notepad. Look for “<add key=”airspy.debug” value=”0″ />” line and change it to value=”1″.

Once the AirSpy and SpyVerter have been connected to the tablet, open SDR# and select AIRSPY in the Source tab. You will see the following configuration dialog.

AirSpy Settings

AirSpy configuration

In the “Sample rate” field, type in “6 MSPS”. For the “Decimation” option, choose “2”. This setting will result in spectrum captures of 3 MHz bandwidth (although only 2.4 MHz of it will be shown on the waterfall display). To capture smaller chunks of the spectrum, increase the decimation value. Make sure the SpyVerter check box is ticked. Do not touch any of the fields or buttons under the “Address Value” line.

Make a short test recording

Press the play button in the top left corner and set the desired frequency.

In the Source tab, select the “Linearity” option. Keep increasing the Gain value by one position at a time until you notice that the radio signals suddenly become “saturated” (the waterfall display becomes full of artefacts and the signal you are listening to gets swamped with noise). Take the Gain value back down by two positions. This will ensure high sensitivity while preventing AirSpy from overloading.

In the Baseband Recorder tab, press “Record”. While recording, do not change the radio frequency and do not move/drag the waterfall portion of the display. Stop the recording after a few minutes.

File Player Plugin

SDR# FilePlayer plugin

In the Source tab, change the input to “File Player” in the drop down menu. Click the Settings cogwheel button and select the spectrum recording file from the MicroSD card. A vertical band visualising the timeline of the spectrum capture will appear immediately to the right of the plugin pane. Click on the play button and select a radio signal to demodulate in the spectrum display. Listen to the audio carefully to make sure there are no dropouts or clicks: if so, your tablet and MicroSD card are capable of handing and storing the specified spectrum bandwidth.

Keep an eye on the gain

While making longer spectrum recordings, select a weak radio signal and keep monitoring its audio for signs of overloading. If the overloading does occur, reduce the Gain value further by one or two positions.

Some example spectrum captures

Shortwave For Lunch

Shortwave for lunch. Playing back parts of the shortwave spectrum captured earlier in the park, inside a local cafe.

Below are some example videos in which I play back and explore the spectrum recordings I made during the trips to my local park.

Tropical and the 49m bands recorded outdoors on 03/07/16 at 0432 UTC. A good time of the day for listening to Latin America on shortwave.



Listening to Radio New Zealand International.

Radio Aparecida from Brazil, usually a challenging catch in Europe.

Comments, suggestions?

Closed Flight Case

Drop me a line in the comments section or hit me up at @LondonShortwave. This article originally appeared on the London Shortwave blog.


promoftiomnov14152016small-copy-copy promoftiomnov12016 promoftiomnov782016small
On November 15 (November 14 local date in the Americas), our special guest will be Cuban Jazz phenomenon Harold López-Nussa, who will share some of his wonderful new album El Viaje. We will also play some new Timba recordings and other excellent Cuban dance music.
Then, the next two weeks, by popular demand, we will rebroadcast our two recent episodes dedicated to JoJazz.
We will return with new episodes in December.

Two options for listening on shortwave:
WBCQ, 7490 KHz, Tuesdays 0100-0200 UTC (8pm-9pm EDT Mondays in the Americas)
Channel 292, 6070 KHz, Tuesdays 1900-2000 UTC (2000-2100 CET)
See  our Facebook page for instructions for listening online if you are out of range or don’t have a shortwave radio.

How to Identify Changes in Station Schedules

The shortwave bands are in a constant state of flux. And radio reception varies with the seasons. As a result, radio stations often need to alter their frequencies and times for best all-year-round reception at the listener’s location. There are two seasonal changeovers: the “A” transmission period coincides with the northern hemisphere summer (March to October), and the “B” transmission schedule for the winter period (October to March). Leading up to these changeovers, broadcasters plan their schedules for the coming season. The B16 transmission season began last weekend.

Want to improve your understanding of shortwave propagation characteristics? Study a few of the strategies employed by broadcast engineers at international radio stations during the twice yearly schedule changeovers. You’ll quickly learn much about how it all works!

Frequency changes by international broadcasters allow you the opportunity to observe the factors that come into play at BOTH the transmitter site and the reception target zone in another part of the world. Broadly speaking, we know that when winter arrives reception of the higher frequencies declines and the lower frequencies provide better reception. The reverse applies in summer – reception on the higher frequencies are enhanced and ionospheric absorption of signals increases at lower frequencies.

In addition, these characteristics change for both daytime and nighttime reception in summer and winter. Furthermore, some interesting reception opportunities occur in certain regions of the world during the summer and winter equinoxes. On top of this, factor in the 11-year sunspot cycle and the current monthly smoothed sunspot number (SSN). So, station engineers have quite a few variables to consider while selecting their preferred shortwave bands when targeting their signals to the listener’s location in some other part of the world! Perhaps one could even consider that these calculations as both a science and an art!


Next, the engineers representing each station have to sit down with their colleagues (competitors?) from other broadcasters and negotiate suitable frequency allocations in each of the preferred bands. This is why we have the existence of the High Frequency Coordination Committee (HFCC). Working together to find and register suitable frequencies that don’t interfere with other transmissions is an important part of successfully ensuring that everyone “wins”. The HFCC describes its role this way:

The main objective of the HFCC is to provide the representation and services for the promotion of an efficient and economical use of the short-wave radio spectrum, and the improvement of radio reception of shortwave broadcast transmissions worldwide……

HFCC’s main activity is a direct coordination of frequencies among frequency managers and specialists of broadcasters, administrations, transmission service providers and other organisations with the aim to facilitate the resolution or minimisation of mutual interference on short waves…..

Membership of the HFCC is open to all individuals and organisations that provide frequency management and planning for recognised shortwave broadcasters.

And it has to be said that the HFCC does a very good job at trying to resolve potential conflicts and clashes in frequency registration. But we didn’t always have this informal governing body. HFCC was only formed in 1990. Prior to that, there was much “rough and tumble” as stations tried to sort it out for themselves and avoid getting in each others way. Remember also, in the 1970s and 80’s there were many more shortwave broadcasters than there are today, each with very large operating schedules. For younger readers here, imagine the international bands being six or seven times busier than they are today!

Understanding propagation characteristics, frequency allocation, antenna beam headings, different time zones and many other aspects of international broadcasting have been a source of fascination for me, both as a shortwave listener and as an amateur (ham) radio operator.

Here are some things to consider when monitoring the change in transmission seasons:

    • Learn the basics of shortwave propagation and the characteristics on display over a 24-hour period, seasonally, annually, and within the sunspot cycle. It’s a big topic and takes a while to really absorb it all!
  • Familiarise yourself with which part of the spectrum the broadcaster can be expected to successfully utilise during a certain season.
    • When finding a station on a new frequency (NF), try to locate and note down the formerly used frequency. Sometimes, that same station will return to the deleted frequency at the start of the next season (the next half of the year).
    • Noting the deleted frequency often reveals that another station has taken up position on that channel.
    • Check to see if the same transmitter site is used for the NF. With so many stations using a variety of relay sites these days, you cannot just assume that the same relay is being used for the NF as it was for the old frequency.
    • Some station schedules are complicated and can be hard to decipher. Time changes, language changes, an increase or decrease in the number of frequencies the station employs for a particular service, daily broadcasts, weekends only, weekdays only, or only certains days of the week can make it tricky to reveal how the NF relates to the old frequency. Expect that you might sometimes get it wrong!
    • A few stations (e.g. China Radio International or Radio Free Asia) use so many outlets for some broadcasts that it can be too hard to tell what was the replaced frequency. In those cases, I just throw up my hands and move on!
  • Maybe the target location of the broadcast has changed. Checking the transmitter’s azimuth beam headings can help here.

Like other “old dudes”, I have spent many years observing and documenting the schedule changes of shortwave broadcasters. This is a part of the hobby that I personally find quite absorbing. However, I’m aware that it’s probably NOT something that some others might enjoy quite so much!

Since the B16 changes came in one week ago, I have been busy monitoring the bands to find the NFs and the deleted frequencies (the ex’s) and any other variations to the broadcasting schedules of each station.

There are HUNDREDS of changes to discover. But I can’t find them all – I also have to eat, sleep, and get on with life!

However, here is a list of the 93 observations I have made over just the past few days:

NOTE: Frequencies in kHz, Times in UTC
ABBREVIATIONS: NF = New Frequency, ex = deleted frequency, QRM = interference, // = another or parallel frequency used at the same time, As = Asia, SEAs = South East Asia, etc. Af = Africa, WAf = West Africa, etc. Eu = Europe, EEu = Eastern Europe, etc. NAm = Nth America, ENAm = Eastern Nth America, etc. Oc = Oceania
FORMAT: Freq – Country of Transmitter site – Station Name – Transmitter Location – comments.

5885 NTH MARIANA IS. RFA – Tinian. Korean to EAs at 1710, NF and good signal, Nov 4.

5910 OMAN. BBC – Al Seela. S/on 1700 in Dari to SEAs, NF, good signal, Nov 4.

5955 ROMANIA. RRI – Tiganesti. Italian to SEu, 1715, NF (ex 5910) and fair signal, Nov 4.

5965 NTH MARIANA IS. RFA – Tinian. Mandarin at 2030, NF and heavy jamming, Oct 31.

5970 TURKEY. VoT – Emirler. French to Eu, 2035, NF (ex 9635), fair signal Oct 31.

5980 TURKEY. VoT – Emirler. Turkish to Eu 2005, NF (ex 9460), good signal, Oct 31.

5990 ROMANIA. RRI – Galbeni. Romanian to Eu, 2040 to s/off 2100, NF (Believed to be ex 9500), good signal, Oct 31.

6010 CHINA. CRI – Urumqi. S/on 1800 in Amoy (Min Nan Chinese), NF (ex 13700) fair signal but QRM from Korean jamming on 6015, Nov 4.

6025 IRAN. VOIRI – Sirjan. German to Eu at s/on 1720, NF (ex 9660), good signal, Nov. 4

6040 CHINA. CRI – Urumqi. Russian to EEu at 1745 to s/off 1757, NF (possibly ex 11875 for this txer site) and excellent signal Nov 4.

6050 TURKEY. VoT – Emirler. English to Eu at 2015 to s/off 2025, NF (ex 9785), fair signal, Oct 31.

6060 IRAN. VOIRI – Zhaedan. Arabic to NAf at 1802, NF (ex 7285), fair signal, Nov 4.

6070 CHINA. CRI – Beijing. Russian to EEu at 1815, NF (ex 9560), very good signal Nov 4.

6090 OMAN. BBC – Al Seela. English WS to CAs and ME, 1820, NF (ex 7375), good signal and // 6195 also heard via Al Seela, Nov 4.

6100 CHINA. CRI – Beijing. English to Eu at 1800-1900, NF (ex 9600), excellent signal and // 7405 (via Beijing) which is also a NF and well heard on Nov 4.

Click here to continue reading the remaining 78 new frequency observations



Part of Rob’s shack. Top Row: Two power supplies. Middle Row: Bose powered speaker, Kenwood R5000 receiver. Bottom Row: Kenwood TS2000 transceiver, Yaesu FRG100 receiver.

Rob Wagner, VK3BVW, is the author of this post and a regular contributor to the SWLing Post. He also blogs at the Mount Evelyn DX Report.

From the Isle of Music for B16


For the B16 season,  our transmission on WBCQ moves to 0100-0200 UTC Tuesdays (which means 8-9pm EST Mondays in the Americas).  On Channel 292, we stay at 1900-2000 UTC Tuesdays, which will now be 2000-2100 CET.
Next week:
JoJazz is the most important competition for young Jazz musicians in Cuba. This week, we will dedicate our entire program to it.
Our November 8 (November 7 in the Americas on WBCQ) program offers music from past JoJazz competitors and an interview with the Joaquin Betancourt, who directs and produces projects involving many of them.
Two options for listening on shortwave:
WBCQ, 7490 KHz, Tuesdays 0100-0200 UTC
(8pm-9pm EDT Mondays in the Americas)
Channel 292, 6070 KHz, Tuesdays 1900-2000 UTC
(2000-2100 CET) (NOTE TIME CHANGE)
See the NOTES section of our Facebook page for more information