We have recently received samples and tested the new R860 tuner chip from Rafael Micro. However, to be clear there is no change in terms of silicon or performance between the R820T2 and the R860. It is just a change in name signifying a minor change in the manufacturing chain which has allowed production of this chip to continue. In the future all R820T2 RTL-SDRs will transition to the R860 and we are just noting this now so that customers are not surprised if they see R860 markings on future dongles. We warn that some sellers of RTL-SDRs may attempt to market the R860 as an improvement, but we want to make clear that they are indeed identical to the R820T2.
Thank you to Rafael for continuing to support the SDR community, and thanks to all our customers!
We note that Airspy will also be using the R860 in their products as per their latest tweet.
Yes, confirmed. The R860 tuners were tested in the #Airspy SDRs with identical performance. This is still very good news compared to the situation when Rafael Micro obsoleted the R820 series. The transition should be smooth this time.
Sarah from the SignalsEverywhere YouTube channel is back and this time showing off a new program she has created called "Pi25" or "OP25 Mobile Control Head". The program is a Python GUI for OP25 which runs on almost any platform including Android and Windows. OP25 is an advanced open source digital voice P25 Phase 2 capable decoder which can be used with an RTL-SDR and run on a Raspberry Pi.
Sarah's GUI software allows information from the OP25 software to be displayed on a nice large Android tablet screen, as well as having scanner forward/back buttons, and talkgroup skip and hold controls. This is very useful for in-car control on a mobile setup.
Sarah notes that she is also considering running a Kickstarter for a physical hardware OP25 head unit controller so please let her know in the YouTube video comments if you are interested.
P25 Police Scanner Control Head OP25 SDR Raspberry Pi or Android GUI Front-End
In his latest episode of his SDR Guide series Rob from Frugal Radio provides a walkthrough on using DSDPlus Fastlane to decode trunked P25 with just one RTL-SDR V3 dongle. In the video he explains each of the various DSDPlus windows, and demonstrates decoding of a Simulcast system in his area.
DSDPlus is a program capable of decoding various digital audio protocols such as DMR and P25. The "Fastlane" version is a $25 paid upgrade which allows you to download the latest version that contains more features.
2021 SDR Guide Episode 9 : $25 DSDPlus P25 LSM trunking walkthrough using 1 x $25 RTL-SDRv3
Over on YouTube "Gadget Talk" has uploaded a useful video showing how he set up an RTL-SDR V3 based panadapter system to use with his traditional amateur radio. The setup involves utilizing an antenna switcher which allows him to transmit with the RTL-SDR connected to the same antenna. The switch grounds the SDR during transmission, ensuring that the RTL-SDR is not overloaded with the transmit signal.
In the video he also shows how to set up the HDSDR receiver software and the HRD Rig Control software for controlling the hardware radio through the software and vice versa.
Over on his YouTube channel TechMinds has uploaded a new video showing how to decode signals from Orbcomm satellites. Orbcomm run a global network of low earth orbit satellites that perform services such as Internet of Things (IoT), Machine 2 Machine (M2M) communications, asset tracking, utilities telemetry, government communications and much more. The signals can be received at around 137 MHz.
In the video he explains how the private client data is encrypted, however it is possible to at least see the encrypted data coming down, and decode some of the data management information such as the transmitted uplink frequencies using a program called Orbcomm Plotter. Ultimately, the data available is quite boring to monitor, however decoding these satellites is still an interesting exercise.
Decoding Orbcomm Satellite Transmissions Using Software Defined Radio
Paolo Romani IZ1MLL has recently created a SDR# users guide document which comprehensively explains all the features and settings available in the program. SDR# (aka SDRSharp) from Airpsy.com is designed for Airspy SDRs, however it is one of the most popular SDR receiver programs used with RTL-SDRs as well.
Paolo's guide appears to build on our own guide at www.rtl-sdr.com/sdrsharp, providing new information and updates since many changes and new features have been released in SDR# since we wrote that guide a few years ago.
The guide can be found on the airspy.com/download page and is available in English, Italian and Spanish.
Cheaper RTL-SDR and SDRs use a low quality crystal oscillator which usually has a large offset from the ideal frequency. Furthermore, that frequency offset will change as the dongle warms up or as the ambient temperature changes. The end result is that any signals received will not be at the correct frequency, and they will drift as the temperature changes. Higher end SDRs and improved RTL-SDRs like our RTL-SDR Blog V3 use a temperature compensated oscillator (TCXO) which has a very small frequency offset and very little temperature drift.
CalibrateSDR can be used with almost any SDR to determine the frequency offset. Andreas notes that CalibrateSDR uses the synchronization channel symbols from DAB+ digital audio stations to determine the offset. His post contains a great explanation of how this works. If you don't have DAB+ in your area, an alternative is Kalibrate-RTL which uses GSM cellphone signals to calibrate.
His results were as expected, showing that the generic RTL-SDRs have large frequency offsets, and his RTL-SDR Blog V3 and LimeSDR have much better precision.
Back in 2017 we posted about Adam 9A4QV's simple V-Dipole antenna design which works very well for receiving NOAA and Meteor weather satellites at 137 MHz. This type of antenna is a lot easier to build compared to a QFH or turnstile, and it results in good performance if built and set up correctly. Over the years he notes that he's received a number of questions asking to clarify the design and so he's uploaded a YouTube video which explains the built and dimensions of the antenna clearly.