Category Archives: Apps

Chris has developed an easy way to run the RTL-SDR dongle on a Mac

Many thanks to Chris Smolinski who writes:

I wanted to run SdrDx, and other SDR apps on my Mac with an RTL SDR Dongle. So I wrote this server app, that makes it appear like a networked SDR.

No need to install any RTL libraries, or compile any code.

Just run the app on your Mac, configure it and your SDR app, and you’re all set.

The app is free, and should work with Mac OS X 10.6 through 10.11.

Chris has kindly allowed me to share his full post here on the SWLing Post below–you can read the original at RadioHobbyist.org:

Running an RTL SDR USB Dongle On Your Mac The Easy Way With Cocoa RTL Server

I’ve had a few of the RTL radio tuner dongles for a while. These are USB devices that were originally made for use as TV tuners overseas, but it turns out that you can access the I/Q data stream, and turn them into an SDR (Software Defined Radio). They can be tuned roughly over a range of 25 to 1700 MHz, and sometimes even higher, depending on the tuner IC chip inside the particular dongle.

I previously posted about how to get the RTL dongle working on the Mac here: An SDR for $17 – The R820T USB RTL-SDR DVB-T Dongle and here: An SDR for $17 – The R820T USB RTL-SDR DVB-T Dongle – Part 2. These posts were from 2013, and I did the installation on a Mac running OS X 10.6, using some pre-built libraries.

Fast forward to the present day. I got a new Mac running OS X 10.11 El Capitan, and I wanted to be able to use the RTL dongles with my favorite SDR software on the Mac,SdrDx. Enter Cocoa RTL Server.

Cocoa RTL Server is a stand alone app that interfaces with an RTL dongle. It does not require you to build or install any drivers or libraries. It just works. It’s based off of an open source app called SoftShell, that I heavily extended. Cocoa RTL Server also acts like a networked SDR, following the RF Space protocol. That means it works with SdrDx, as well as any other SDR app on the Mac that supports RF Space SDRs like the netSDR. You can download a copy of the app from the Cocoa RTL Server page. Source code is included, however I am not offering any support for the project or final app.

Here’s a screenshot of the app running:

Getting up and running is easy:

1. Plug in your RTL device
2. Run CocoaRTLServer 2.0
3. Select the device from the popup menu (usually it is already selected)
4. Change the rtl_tcp or tx_tcp port values if needed
5. Click Open
6. Configure your SDR app (set the correct TCP port) and run it

I’ve run it under Mac OS X 10.6, 10.10 and 10.11, It should run under 10.7-10.9 as well.

Using SdrDx, I can tune a large portion of the FM broadcast band, click to view full size:

In this case I am tuned to 97.9 MHz. To the left of the signal meter, you can see it has decoded the station ID from the RDS data. Yes, SdrDx decodes RDS.

If you look at the lower right corner, you see the scope display of the demodulated FM audio. There are markers for the portions of interest:
You can see the main audio above the green marker to the left.
The stereo pilot at 19 kHz (red marker).
The stereo subcarrier (aquamarine)
The RDS data (orange)
The 67 kHz SCA subcarrier (purple)
The 92 kHz SCA subcarrier (yellow)

Cocoa RTL Server also includes a server that emulates rtl_tcp, so it works withCocoa1090 which decodes aircraft transponders that transmit on 1090 MHz. It should also work with any other app that gets data from rtl_tcp. Here’s a screenshot of Cocoa1090 running:

Thanks so much for developing this app, Chris!

I think I might go ahead and pull the trigger on an RTL-SDR as it would be great to run one on my Mac. I think your app will make the process much easier.

Readers: make sure you check out Chris’ blog RadioHobbyist.org.

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A Review of Multipsk Software for Digital Modes and More

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Over the last year or so I have been using a really full-featured digital mode software called Multipsk, and it has become my go-to software for most digital modes. Back in September 2015 I wrote an extensive review of the software for The Spectrum Monitor (TSM) which Owner/Editor Ken Reitz has graciously allowed me to post on my blog at All Things Radio. Thomas has written numerous articles for TSM, and will attest to its emphasis on so many aspects of the radio hobby. If you are not a subscriber already you really do not know what you are missing!

The program boasts over 75 modes, not counting some of the many sub-modes or variations, and new modes are being added all the time. There is a free version and a registered version, with the paid mode costing around $45 (U.S.) The free mode will handle a lot of really great modes, but I confess, it was the additional “professional” modes which really made purchasing the registered version a must for me. Whichever way you go, you will not be disappointed. As I have noted on my blog and in the article itself, I consider the registration fee some of the best money I have ever spent for computer software.

As an added bonus, the free or registered version can be run on as many computers as you have in your home, and multiple instances of the program can be run on the same computer provided they are in separate directories. This is a great feature, and it means there is basically nothing going into the Windows registry file–the program runs right from the directory. My only problem is not having enough antennas to have as many instances of the program running as I would like!

I hope you will take time to read my review and then get the program–I think you will be suitably impressed as I was! (I have it running on XP machines through Win10, so compatibility should not be an issue.)

Robert Gulley, AK3Q, is the author of this post and a regular contributor to the SWLing Post. Robert also blogs at All Things Radio.

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The Architecture of Radio iOS and (soon) Android App

An iPhone app and Paul’s secret for successful reception reports

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Many thanks to SWLing Post contributor, Paul Walker, who writes:

Wether you do AM, shortwave, longwave, FM or something else, I think this will prove useful.

I have a pretty high return rate when submitting reception reports and asking for QSL cards/letters. I’d say my return rate is probably better than 60 percent, sometimes even 70 or 80 percent. It just depends.

But what helps me so much? EVERY reception report I email or snail mail includes an audio recording. Sometimes it’s only 30 seconds if the signal is really rough, weak or hard to pick out anything useable. Sometimes I include anywhere between 5 minutes and 30 minutes with a detailed report.

Well, how do I record? I use my smartphone! I have an iPhone 6 Plus with 128 GB of storage. iPhones record some of the best audio I’ve ever heard from a smartphone. Androids do a pretty decent job–not as good, but not bad.

The best app I’ve found for this is Voice Recorder Pro 7.

Click here to view Voice Recorder Pro 7 on iTunes.

Voice Recorder Pro 7 Screenshots

You can select the recording format (mp4, mp3 or wav), you can select the sample rate, bit rate (32kbps all the way up to 320kbps), you can select mono or stereo as well.

But where this really comes in handy? You can email the audio file to yourself or someone with the click of a button, you can upload it to a google drive, dropbox, one drive or a box cloud account. You can even have it upload to an FTP server or to your Facebook page if you want!!

The one feature I like is being able to turn audio into a YouTube video and uploading it directly! I was recording videos by holding it up to the radio’s display and while the audio was good, it wasn’t great because it was a bit further away from the speaker so I could show the S meter and frequency on the display.

So what I ended up doing is to put the phone right near the radio’s speaker and start recording… this produces better audio then a straight up video. Then you click a button after the recording is over and it generates the video frames for you, putting a picture there; you fill in the particulars of your video and it uploads it to your YouTube account.

See what I’m talking about here, by viewing my YouTube account:
https://www.youtube.com/user/OnAirDJPaulWalker

You can easily tell which videos were made by me holding up the phone to the radio’s display and which are audio only with the video generated by Voice Recorder Pro 7.

Here’s an audio only track I recorded to give you an idea how it sounds.

https://soundcloud.com/paul-walker-11/radio-mediterranne-international

I don’t recall if they have this app for Android phones, but if they don’t, there’s something similar. It’s worth investigating.

A detailed written report is one thing when requesting a QSL, but audio is indisputable and absolute confirmation of what was heard.

Many thanks for the recommendation, Paul. I use an Android phone (the Moto X 2nd generation). I’m hoping a Post reader can suggest a recording app that is equally robust.

Like you, I typically send an audio recording when submitting a reception report. It’s certainly a valuable piece of information for broadcast engineers. Thanks again!

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More from 1 Radio News developer Steven Clift

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After publishing a post about the new 1 Radio News app, developer Steven Clift commented:

Thanks for the mention!

I had a private email in my draft box for Tom … here, I’ll share with all:

Thomas, Ken Reitz suggested you would be a good person to reach out to about my app.

In the days before the Internet, I can remember taking my shortwave radio up to my Grandparents in far northern Minnesota. I’d have the time to be “closer to the world” by listening global broadcasters like the BBC World Service and be intrigued by Cold War broadcasts from the Soviet Union and Cuba giving a decidedly different view.

As my Uncle gave me my first shortwave radio, what might one give to a teen today to easily expose them to the world of truly global news. Now there is an app for that: http://1radionews.com

In 1993, when I first went online, my novice thought was this might be like “reception clear shortwave.” Going to the world.

I had forgotten that early thought until a few days ago when I added 30+ live English news streams from broadcasters around the world into the pro version of my 1RadioNews.com Android radio app.

I started channel surfing … what’s on here, fun, OK how about this station. What are Radio Sputnik and Radio China International up to … oh and Wisconsin Public Radio has some great original programming. So now I can go even deeper in my explorations of the voices around the world. I could discover radio, discover the world again through the power of sound and the human voice right on my mobile – quickly and easily.

FYI – “Pro” version has 3 times more – curated and well tested – streams, but the free ad-supported version has some classics like the BBC World Service. I tied to make the app “thumbable” meaning you can just hold the phone and swipe and press a button to play. Super simple and a lot quicker than apps with literally ten of thousands of stations. Saving ten seconds to switch the station matters!”

Many thanks for the insight, Steven! Since most of us SWLs are international “news junkies,” we appreciate having a curated, simple interface to hear top of the hour news from our favorite broadcasters.

By the way, Steven, I have added 1 Radio News to our list of the best apps for Shortwave and Ham radio enthusiasts–one of our most popular all-time posts. Good luck and we look forward to hearing about any future developments!

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1 Radio News equivalent for iPhone

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Regarding the new 1 Radio News App for Android devices, SWLing Post reader, Erica comments:

“I too wish 1 Radio News were available for iPhone. The nearest thing I know of however is an app called Hourly News. It allows you to listen to latest news bulletins from various news outlets.

Most news sources included are American broadcasters, but it does have Deutsche Welle, RTHK and VOA. You can also add podcast feeds to expand what you can hear. I hope this is useful to you all.

Many thanks, Erica. I use an iPhone when I’m on the move, so I’ll give this app a try!

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Mobile news app inspired by shortwave radio

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Many thanks to SWLing Post contributor, Richard Cuff, for sharing the following article from TwinCities.com. The following is an excerpt:

Twin Cities developer creates ‘shortwave radio’ app for world news

By Julio Ojeda-Zapata

Smartphone users have no shortage of radio-style apps that will stream news-and-information programming to them over the Internet.

But app developers are always in search of niches within well-populated app categories, and Twin Cities resident Steven Clift thinks he’s found one.

He’s released an app called 1 Radio News that provides news-related audio from around the world for English speakers who are eager to keep up on the latest global happenings.

But, unlike other such apps like TuneIn Radio and iHeartRadio that are crammed with hundreds or thousands of audio sources, 1 Radio News aggressively culls options to just a few dozen.

[…]Clift is known in local Internet circles as the executive director of E-Democracy.org, a network of neighborhood forums that also has served as an election-information site. This is Clift’s first foray into app publishing.

[…]Clift’s app is no Android blockbuster yet, but he said he’s seen interest from all over the world — notably of late from unexpected locales like Malaysia, Nigeria and Pakistan.

For Clift, the app is in a way the realization of a childhood dream. When he was growing up in Winona, Minn., the geography where he lived made TV reception problematic. But he had little trouble pulling in short-wave radio signals from around the world.

Now, his app “turns a phone into a global short-wave radio filled with high-quality news sources from all over the world,” he said.