Over on his YouTube channel Crazy Danish Hacker has posted a new video that shows how to pick up amateur radio voice signals from the International Space Station (ISS).
Often astronauts on the ISS will schedule times to chat with schools via amateur radio frequencies. This provides an opportunity to learn about radio whilst at the same time allowing kids to talk directly to an astronaut.
If you live in an area that can 'see' the ISS at the same time as the school then you can easily pick up the downlink (astronaut to ground) portion of the conversation while the ISS passes over. The downlink signal is fairly strong, so only a simple antenna is required. In his video Crazy Danish Hacker uses a telescopic whip attached directly to his RTL-SDR which is placed outside with a view of the sky.
International Space Station - Software Defined Radio Series #29
Most police departments is the USA have now upgraded or are in the process of upgrading their radio systems to P25 Phase 2 digital radio. The frequencies can easily be received with an RTL-SDR, but a decoder is required to be able to actually listen to the voice. Software like SDRTrunk and DSDPlus can decode P25 Phase 1, but at the moment the only software that is capable of decoding P25 Phase 1 AND 2 is a program called OP25. However, OP25 has a reputation of being fairly difficult to set up as it does not have a simple to use GUI, and requires Linux.
Over on John's Tech Blog, John has uploaded a very helpful step by step tutorial that should help with those trying to get OP25 to work. The tutorial assumes that you have Ubuntu 18.04 already installed, and then starts from downloading and installing OP25. The next steps involve setting up OP25 for the particular system in your area, which mostly involves just editing a spreadsheet to input frequency data from radioreference.com. John also mentions that he's been able to get OP25 running perfectly on a Raspberry Pi 3 B+ as well, with less than 40% CPU usage.
OP25 Running
In the video below John reviews some of the steps, and shows OP25 running and decoding voice.
Over on our forums one user luc4sss has been discussing a method for using RTL-SDR's and perhaps other SDR dongles remotely which does not rely on rtl_tcp, SpyServer or other SDR specific server software. Using an SDR remotely is advantageous because it can allow you to position the SDR closer to the antenna, which results in less signal loss from long runs of lossy coax cable.
Instead of rtl_tcp, luc4sss uses a program called VirtualHere, which is a server that can work with any USB device. It essentially allows you to use USB devices over a network with the remote device acting as if it was plugged directly into your remotely operated PC. The server can run on single board Linux computers like the Raspberry Pi and luc4sss has been using an $8 Orange Pi Zero 256 MB as his server.
With the VirtualHere software and RTL-SDR running on his Orange Pi Zero, he's able to connect to a remote RTL-SDR over his network. He writes that data usage is about 5 - 6 MB/s so a wired Ethernet connection or high quality WiFi connection would be required. In comparison rtl_tcp should use about the same amount of data, but server software with some compression and data saving techniques implemented like SpyServer use much less data and is efficient enough to be used over the internet.
We can see the VirtualHere software being very useful for use with RTL-SDR compatible programs that don't have rtl_tcp support, which is most of them. It should also be useful for other SDRs that don't have streaming server software available.
VirtalHere is not free as a license costs $49. But it does have a 10-day trial period which supports 1 device being shared at a time.
VirtualHere USB Network Server
Luc4sss has also uploaded a video on YouTube that shows him running the VirtualHere server and client, and connecting to the remote RTL-SDR with GQRX and dump1090. He also shows the data usage which is about 6 MB/s when running the RTL-SDR at 2.8 MSPS. Operation appears to be problem free and with almost entirely no latency as well.
RTL-SDR over Ethernet with VirtualHere Client/Server
Over on his YouTube channel Tech Minds has recently uploaded a video that demonstrates and shows how to use the rtl_433 software with an RTL-SDR to decode 433 MHz ISM band low power devices. Typically these devices include things like home wireless temperature and weather sensors, tire pressure sensors, remote controls, and other various sensors.
In the video he sets up an RTL-SDR and magmount antenna by his window and is able to receive data from several of his neighbors weather stations, and some car key remotes. He shows how to run the software on both Linux and on Windows.
How To Decode 433Mhz Low Power Devices Using RTL433 And A RTL-SDR Receiver
Over on our store we've just released two new products for sale. The first is a metal case upgrade kit for the SDRplay RSP1A. It is similar to the previous enclosure that we sold for the RSP1, but no longer comes with an included BCFM filter since the RSP1A has this filter built in as a software switchable option.
Instead we've included a portable 7 meter (23 feet) long wire antenna spool (Tecsun AN-03L) with SMA adapter, and an 11 cm to 48 cm adjustable SMA telescopic antenna. The 7 meter antenna is great for HF SWLing, and neatly rolls up into the spool for travelling. The telescopic antenna is a portable VHF/UHF antenna that can plug directly into the SMA port of the RSP1A. Both antennas fit neatly into the supplied semi-hardshell carry case. The set costs US$29.95 including shipping and is available on our store, and will be on US Amazon in a couple of weeks.
The second product is the portable antenna set just by itself. The set includes the 7m Tecsun AN-03L antenna spool, the mono plug to SMA adapter and the 11 cm to 48 cm telescopic antenna. It can be used on any SDR with SMA ports. The set costs US$11.95 and is also available on our store. It will also be on Amazon in a couple of weeks.
Over on his YouTube channel Crazy Danish Hacker has posted a new video that shows how to pick up amateur radio voice signals from the International Space Station (ISS).
Often astronauts on the ISS will schedule times to chat with schools via amateur radio frequencies. This provides an opportunity to learn about radio whilst at the same time allowing kids to talk directly to an astronaut.
If you live in an area that can 'see' the ISS at the same time as the school then you can easily pick up the downlink (astronaut to ground) portion of the conversation while the ISS passes over. The downlink signal is fairly strong, so only a simple antenna is required. In his video Crazy Danish Hacker uses a telescopic whip attached directly to his RTL-SDR which is placed outside with a view of the sky.
International Space Station - Software Defined Radio Series #29
Most police departments is the USA have now upgraded or are in the process of upgrading their radio systems to P25 Phase 2 digital radio. The frequencies can easily be received with an RTL-SDR, but a decoder is required to be able to actually listen to the voice. Software like SDRTrunk and DSDPlus can decode P25 Phase 1, but at the moment the only software that is capable of decoding P25 Phase 1 AND 2 is a program called OP25. However, OP25 has a reputation of being fairly difficult to set up as it does not have a simple to use GUI, and requires Linux.
Over on John's Tech Blog, John has uploaded a very helpful step by step tutorial that should help with those trying to get OP25 to work. The tutorial assumes that you have Ubuntu 18.04 already installed, and then starts from downloading and installing OP25. The next steps involve setting up OP25 for the particular system in your area, which mostly involves just editing a spreadsheet to input frequency data from radioreference.com. John also mentions that he's been able to get OP25 running perfectly on a Raspberry Pi 3 B+ as well, with less than 40% CPU usage.
OP25 Running
In the video below John reviews some of the steps, and shows OP25 running and decoding voice.
Over on our forums one user luc4sss has been discussing a method for using RTL-SDR's and perhaps other SDR dongles remotely which does not rely on rtl_tcp, SpyServer or other SDR specific server software. Using an SDR remotely is advantageous because it can allow you to position the SDR closer to the antenna, which results in less signal loss from long runs of lossy coax cable.
Instead of rtl_tcp, luc4sss uses a program called VirtualHere, which is a server that can work with any USB device. It essentially allows you to use USB devices over a network with the remote device acting as if it was plugged directly into your remotely operated PC. The server can run on single board Linux computers like the Raspberry Pi and luc4sss has been using an $8 Orange Pi Zero 256 MB as his server.
With the VirtualHere software and RTL-SDR running on his Orange Pi Zero, he's able to connect to a remote RTL-SDR over his network. He writes that data usage is about 5 - 6 MB/s so a wired Ethernet connection or high quality WiFi connection would be required. In comparison rtl_tcp should use about the same amount of data, but server software with some compression and data saving techniques implemented like SpyServer use much less data and is efficient enough to be used over the internet.
We can see the VirtualHere software being very useful for use with RTL-SDR compatible programs that don't have rtl_tcp support, which is most of them. It should also be useful for other SDRs that don't have streaming server software available.
VirtalHere is not free as a license costs $49. But it does have a 10-day trial period which supports 1 device being shared at a time.
VirtualHere USB Network Server
Luc4sss has also uploaded a video on YouTube that shows him running the VirtualHere server and client, and connecting to the remote RTL-SDR with GQRX and dump1090. He also shows the data usage which is about 6 MB/s when running the RTL-SDR at 2.8 MSPS. Operation appears to be problem free and with almost entirely no latency as well.
RTL-SDR over Ethernet with VirtualHere Client/Server
Over on his YouTube channel Tech Minds has recently uploaded a video that demonstrates and shows how to use the rtl_433 software with an RTL-SDR to decode 433 MHz ISM band low power devices. Typically these devices include things like home wireless temperature and weather sensors, tire pressure sensors, remote controls, and other various sensors.
In the video he sets up an RTL-SDR and magmount antenna by his window and is able to receive data from several of his neighbors weather stations, and some car key remotes. He shows how to run the software on both Linux and on Windows.
How To Decode 433Mhz Low Power Devices Using RTL433 And A RTL-SDR Receiver
Over on our store we've just released two new products for sale. The first is a metal case upgrade kit for the SDRplay RSP1A. It is similar to the previous enclosure that we sold for the RSP1, but no longer comes with an included BCFM filter since the RSP1A has this filter built in as a software switchable option.
Instead we've included a portable 7 meter (23 feet) long wire antenna spool (Tecsun AN-03L) with SMA adapter, and an 11 cm to 48 cm adjustable SMA telescopic antenna. The 7 meter antenna is great for HF SWLing, and neatly rolls up into the spool for travelling. The telescopic antenna is a portable VHF/UHF antenna that can plug directly into the SMA port of the RSP1A. Both antennas fit neatly into the supplied semi-hardshell carry case. The set costs US$29.95 including shipping and is available on our store, and will be on US Amazon in a couple of weeks.
The second product is the portable antenna set just by itself. The set includes the 7m Tecsun AN-03L antenna spool, the mono plug to SMA adapter and the 11 cm to 48 cm telescopic antenna. It can be used on any SDR with SMA ports. The set costs US$11.95 and is also available on our store. It will also be on Amazon in a couple of weeks.
Recently we've found that there are now cloned units of SDRplay RSP1 and Airspy R2 units appearing on Aliexpress and eBay. (We won't link them here to avoid improving the Google ranking of the clone listings). This post is just a warning and reminder that these are not official products of SDRplay or Airspy, and as such you would not receive any support if something went wrong with them. The performance and long term software support of the clones also isn't known. Buying clones also damages the original developers abilities to bring out exciting new products like we've seen so far constantly with Airspy and SDRplay.
SDRplay
We've been in contact with SDRplay for a statement and they believe that the unit is a clone of the older and now discontinued RSP1, and not the RSP1A, despite the listings advertising RSP1A features such as additional filtering. SDRplay note from the pictures of the circuit board that the cloned unit's circuit board looks like an RSP1, and that the listing description is probably just blindly copied directly from the official RSP1A description.
Currently given that the price of the cloned RSP1 is $139, which is higher than the $109 cost of an original and newer model RSP1A, we don't see many taking up the offer.
Airspy
The Airspy R2 has also recently been cloned and now appears on Aliexpress with the lowest price being US$139 without any metal enclosure. Given that the price of an original Airspy R2 with metal enclosure is US$169, we again don't see many taking up the offer of the clone with such a small price difference.
HackRF
The HackRF is a different story in respect to clones. The HackRF design and circuits are open source, so unlike the closed source designs of the SDRplay and Airspy, in a way HackRF clones are actually encouraged and are legal. For some time now it's been possible to find cloned HackRF's on Aliexpress for only US$120 at the lowest, and from $150 - $200 including antennas and TCXO upgrades. This is quite a saving on the $299+ cost of the original HackRF. Reports from buyers indicate that the HackRF clones are actually decent and work well. The advantage of buying the original version is that you support Michael Ossmann, the creator of the HackRF, and may potentially get a better performing unit.
We've also seen clones of the HackRF Portapack on Aliexpress, which is an add-on for the HackRF that allows you to go portable. The clones go for $139 vs $220 for the original. No word yet on the quality.
RTL-SDR V3
We also note that recently there have been several green color RTL-SDRs released on the market with some being advertised as "RTL-SDR Blog V3" units. These are not our units, and are not even actual clones of the V3. These green units appear to just be standard RTL-SDRs without any real improvements apart from a TCXO. Some listings even advertise the V3's bias tee and HF features, but they are not implemented. Real V3 units come in a silver enclosure branded with RTL-SDR.COM.
Final Words
If you know how China works, you'll understand that it's highly unlikely that there is any legal recourse for SDRplay and Airspy to remove these products from sale. Once a product is popular it is almost a given that it will be cloned. It's possible that the clones might be able to be gimped via blacklisting official software, but that the companies would implement this is a stretch, and would probably be easy to get around. In the end while not ethical in a business fairness sense, these clones may be good for the consumer as they force the original designers to lower their prices and improve added value services.
If readers are interested in a comparison between the clones and original units, please let us know as we may consider an article on it.
A radiosonde is a small weather sensor package that is typically attached to a weather balloon. As it rises into the atmosphere it measures parameters such as temperature, humidity, pressure, GPS location etc, and transmits this data back down to a receiver base station using a radio signal. The RS41 is one of the newer radiosonde modules sold by radiosonde manufacturer Vaisala, and is currently one of the most popular radiosondes in use by meteorological agencies. The signal is typically found at around 400 MHz and can be received with an RTL-SDR and an antenna tuned for 400 MHz. We have a general tutorial on radiosonde decoding available here.
There are several software packages that can decode RS41 data, such as the multi-radiosonde decoder Windows program called SondeMonitor (25 euros), or the free Linux command line software called RS. Recently a new free Windows GUI based RS41 decoder has been released by IW1GIS. The software can display on Google maps the current location and previous path of the radiosonde, as well as it's weather data telemetry.
Main features are:
Directly decoding of GFSK signal received by the FM radio receiver (the use of a Software Defined Radio is recommended).
Capability to connect and command SDRSharp software by mean of Net Remote Control plugin.
Advanced frequencies scan and decode: RS41 Tracker is able to look for RS41 radiosonde signal in a given list of frequencies, starting the radiosonde decoding when a valid signal is detected.
Real time showing radiosonde position on google map (internet connection is required)
Map auto centered on radiosonde position
Map type selectable by user (road, satellite, hybrid, terrain).
Burst killer detailed information and launch time estimation.
Radiosonde RAW data save
Post processing of RS41 RAW data file
Tracking information (elevation, bearing, slant range)
Over on our forums user thewraith2008 has just released news about his new software called TETRA Trunk Tracker. The software works in conjunction with the TETRA demodulator plugin for SDR#. It works by using two dongles, one to monitor a TETRA trunking channel, and the other to decode voice audio, although a single receiver mode is also available which works with a reduced and fixed bandwidth.
TETRA Trunk Tracker
The post reads:
TETRA Trunk Tracker will follow calls on a TETRA network.
TETRA Trunk Tracker reads DATA that is output from the SDR# plug-in TETRA Demodulator (by TSSDR) via the 'Network Info' calls log window.
It interprets this DATA to determine when a call is set-up, then instructs SDR# (VC) to move to the carrier (frequency) that the call will be on.
It will also watch out for other PDUs to determine when a SSI starts or completes transmissions and when calls are complete (Released).
Features:
A basic call recording (All or Selective call recording).
Display current call details with list of seen SSIs for that call. (SSI populate as they TX).
GSSI holding - will only allow calls with selected GSSI to be heard.
Call lockout based on GSSI. Can be unchecked in list to lockout GSSI.
Call Priority. (Only normal version)
GSSI weighted 0-9, 9 is highest. If on active call and other call event occurs, if new call has higher
priority then will switch to it.
Collect/Save all seen GSSIs with Labels and Priority, By Network.
Collect/Save seen SSIs with Labels and Last seen Date/Time, By Network.
Set a call time-out. Returns to idle state if call does not see a release PDU after X time in seconds.
Log call events to screen and file, if enabled.
Log raw CC and VC PDU messages as seen by the 'TETRA Demodulator' plug-in, if enabled.
Log GSSI daily call activity. (Simple version does not play calls when this is selected)
Set base frequency via UI.
Set CC park carrier # via UI.
Set VC park carrier # via UI.
Suppress some PDUs. (unchecked is mainly for testing only)
Suppress lockout messages.
Sort SSI and GSSIs/Lockouts (by GSSI). This only occurs on start-up.
Country Code label, defined via file (shown as menu item)
Network label, defined via file (shown in tool tip where MNC,LA is in 'Call Details' panel)
Location Area label, defined via file (shown in tool tip where MNC,LA is in 'Call Details' panel) Only shown when Network label used.
Ignores Encrypted PDUs (with no reference to them)
Set a seen GSSI priority via UI.
Update a seen GSSI/SSI label via UI.
Call active indicator.
Restore SDR# windows to a defined position.
If the TETRA Demodulator does not work for you this program will do nothing to change that.
This is the third release of this program. (TETRA Trunk Tracker v0.99.6) And 2nd release for (TETRA Trunk Tracker v0.99.6s - Simple)
Two versions are available:
Normal (Uses 2 SDR# and 2 Dongles) with TETRA Demodulator and Net Remote plug-ins
Simple (Uses 1 SDR# and 1 Dongles with some features not available) with TETRA Demodulator and Net Remote plug-ins
Backup your "Tetra-trunk-tracker.dat" settings file. Then delete "Tetra-trunk-tracker.dat" as it has changed and old one will cause error on load.
Some work as gone into trying to make TETRA Trunk Tracker easier to run once the initial setup has been done.
A MCC (Country Code) label file is included for your convenience "TETRA_mcc.txt".
It has only been tested on Windows 7 - Professional SP1 (32 bit), English
You MUST have a PC that is capable of running SDR# x 2 with the TETRA plug-in. (Not overloaded CPU usage.)
It is in alpha stage. This means is may contain errors that may cause issues with the other programs it works with. i.e. crashing them or itself.
The TETRA plug-in currently been developed by TSSDR is also in early development. Because of this any changes made in plug-in releases most likely will break this program.
I have created it to suit my needs. And it currently works for me with the TETRA network I monitor.
I make no claim that it will work for other networks.
Please read the provided files for set-up and usage:
TTT_set-up_manual.pdf
TTT_Features_and_Usage.pdf
I have tried to be as thorough as possible with the documentation to explain usage and features. I believe any questions can be answered by reading these files. These files most likely are not complete and contain errors and are not laid out as good as they could be.
It only works with the provided TETRA plug-in supplied in zip. (2018-June-06). This version uses a custom compiled version of 'Net Remote' supplied in zip
It is only meant to be a temporary solution until something better comes along.
