OSX users often don’t have much choice when it comes to general purpose SDR receiver software for the RTL-SDR or other SDR’s. However, one program that works well on Macs is GQRX. Installing GQRX on OSX can sometimes be difficult as the most common installation method involves using Macports, which won’t always work depending on the version of OSX you are using.
Recently, OSX and RTL-SDR user smittix wrote in to use to let us know that there is now a very easy way for El Capitan OSX users to install GQRX. Basically the GQRX team have now released a DMG file which can be downloaded and installed just like most other easy to use applications. Using the DMG file smittix was able to get up and running within 5 minutes.
Every year politicians and business men meet at the “World Economic Forum” in the small mountain town of Davos, Switzerland to discuss various topics and create business deals. This year Quartz, an online newspaper/magazine sent a journalist to the forum. However, the journalist wasn’t tasked with writing a conventional story about the forum topics – instead he was asked to use an RTL-SDR to monitor the private helicopter traffic coming in and out of Davos using ADS-B data. They write that their reasoning for doing this as follows:
We went to all this trouble because there is perennial fascination with the flying habits of the 2,800 Davos delegates. Use of private aircraft, though often wildly overstated, highlights the vast wealth and power that descends upon this small skiing town in the Swiss Alps each year. And their transportation choices are frequently criticized for their environmental impact at a conference that seeks solutions to reducing carbon emissions, among other topics.
Using an RTL-SDR dongle, Raspberry Pi and ADS-B collinear antenna they monitored the flights over Davos. From the data they were able to determine the flight paths that many helicopters took, the types of helicopters used and the most popular flight times. They were able to identify 16 private helicopters that were used, although they write that some may not have had their ADS-B transponders turned on.
The RTL-SDR and various other components used to track the helicopters.The flight path taken by the private helicopters.
AISRec is an RTL-SDR compatible AIS decoder that is made for Windows and Android. AIS is an acronym for Automatic Identification System and is a system used by ships to broadcast position and vessel information. By monitoring AIS transmissions with the RTL-SDR we can build a boat radar system. We have a tutorial on this here (using other software).
The last time we tried AISRec we found that it had very good ability at decoding AIS messages, especially very weak ones and was by far the easiest AIS decoder to set up and use on Windows. The features include:
1. Work with all rtlsdr dongles. Allow future support for other SDR devices. 2. Stable reception of AIS signals at as low as SNR 7 dB. 3. Tolerance to frequency drifts > 30 ppm. 4. Dual-channel reception at 161.975 MHz and 162.025 MHz. 5. Channel selectivity > 56 dB. 6. Low CPU usage. No problem for Atom CPU and above. 7. Output all types of AIS messages (including Class A and Class B) in NMEA formats to UDP ports. 8. Convertion of AIVDM to AIVDO messages for your own ship. 9. Display of the received NMEA messages and the statistics.
The author of AISRec writes in an email to us an explains that the trial version has a time limit and an RX message count limit for each run, whereas the registered lite version will not. The pro version will have some additional features. Currently the author has no method for taking in paid registrations, but plans to have this ready in the future. We will post again once registration is available.
10x NESDR Nano 2+ sets (a.k.a R820T2 w/ TCXO RTL-SDR in small “nano” package)
15x NESDR Nano 2 sets (a.k.a R820T2 RTL-SDR in small “nano” package)
To enter all you need to do is comment on their blog post (not ours!). Their competition runs from 24 January 2016 20:00 UTC to 31 January 2016 20:00 UTC.
In the latest update they have also added support for the RTL-SDR on OSX. An RTL-SDR dongle is able to connect to the SdrDx program via a special OSX based RTL-SDR server called CocoaRTLServer. At the moment it appears that rtl_tcp is not supported as it does not use the protocol required by SdrDx, so Windows and Linux computers cannot use this software.
Compared to other general purpose SDR receiving software SdrDx has some interesting features not seen in most SDR software that supports the RTL-SDR. The full feature list and list of currently supports SDRs can be found here.
Over on YouTube Adam Alicajic (9A4QV – creator of the LNA4ALL and upcoming MIX4ALL) has uploaded a video showing his reception of AERO-H signals from an Inmarsat satellite. A few days ago we posted about how the JAERO decoder had recently been updated to be able to decode these AERO-H signals. These signals contain various messages meant for airplanes, but also sometimes contain news messages.
In the video Adam uses a satellite dish antenna together with his MIX4ALL, an RTL-SDR dongle and the JAERO software. With decent reception he is able to easily decode the AERO-H messages.
Currently we at RTL-SDR.com are selling upgraded RTL-SDR dongles on our store. We’ve worked hard to reduce the most common issues that the cheapest generic dongles have, whilst trying to not significantly increase the retail price so that these devices stay ubiquitous. In each batch that we’ve produced so far we’ve tried to make some improvements over the last. Previously we’ve added a TCXO, SMA connector, and bias tee and now in the latest batch we’ve added a metal case and passive cooling.
The new units have been in stock at our Chinese warehouse for almost a month now, and they are now back in stock at Amazon USA as well (shipping soon). They are priced the same as before: $24.95 USD for the unit with antennas and $19.95 USD for the dongle only. If you order from the Chinese warehouse all units come with free registered air mail shipping (1-4 week delivery), and free shipping is available on Amazon for USA customers (<1 week delivery) if you are a Prime member or spend over $35.
Aluminium case. We’ve upgraded from a plastic case and now all units come with an aluminium case standard. The aluminium is 1mm thick and is treated with an anti-anodizing coating to improve conductivity. However, some natural anodization still occurs. The dimensions are similar to the plastic case at 69 mm x 27 mm x 13 mm.
The new RTL-SDR dongle design with aluminium case.
Ground tracks on the PCB. The PCB size has been increased slightly to accommodate side ground tracks. These ground tracks should make contact with the aluminium and provide ground conductivity to the case.
New RTL-SDR PCB with side ground tracks.
Passive cooling. As the case is now metal we can apply a thermal interface material between the PCB bottom and case wall. The interface material we’ve chosen is a 3mm thermal pad. This is a soft silicon pad with high thermal conductivity. This appears to provide adequate cooling to ensure the dongles run properly at above 1.5 GHz.
Thermal pad on the bottom of the PCB for improved heat dissipation.
The metal case and side ground tracks should reduce the amount of interference received by the dongle through sources other than the antenna. The passive cooling should also be enough to ensure that the dongles run properly at above 1.5 GHz, though we still would recommend running them in a cool shady place, rather than out in the direct sun if monitoring L-band signals. If you find that the conductivity between the PCB and case is not good enough, then you can try thickening the side ground tracks on the PCB with a layer of solder – we will be trying to increase the thickness by default in subsequent batches.
Soon we will also have the metal cases for sale by themselves for those who want to upgrade from a previous batch (EDIT: Now on sale!). Though please note that although the older SMA PCBs fit in this case, the previous batches PCB’s are a little smaller than what this case takes so it may fit a little loosely. The old PCB’s also don’t have the side ground tracks for improved conductivity, but even with no ground conductivity it is still possible for the case to work as a Faraday cage. These cases will be available on the store page in a few days at a very low cost and they will only be available only from the Chinese warehouse.
Once again we hope people will enjoy these changes, and feel free to let us know what you think and what you might like to see in the future.
The JAERO decoder for AERO signals on Inmarsat satellites has recently been updated to version 1.03. This new version supports the decoding of 10.5k Aero-H and Aero-H+ signals. The author of JAERO Jonti writes that on these channels he’s seeing significantly more traffic than on the narrowband signals and that he was suprised to see that other non-aircraft messages such news was broadcast on this 10.5k signal. Jonti writes about his experience in developing the 10.5k decoder and his experience with receiving the messages in this post.
Jonti discovered that news updates are also broadcast on 10.5k AERO.What the 10.5k signals look like compared to the 600 signals.
If you like Jonti’s apps, then please remember to donate a small amount to him so that he can continue to work on them more. His PayPal donate button can be at the bottom of his main page.
