In his most recent work Job has managed to detect the W3 star forming region at the Hydroxyl (OH) frequency of 1665.405 MHz.
W3 is an enormous stellar nursery about 6200 light-years away in the Perseus Arm, one of the Milky Way galaxy's main spiral arms, that hosts both low- and high-mass star formation. - Source
Hydroxyl (OH) can be observed both in emission and absorption. Emission frequently manifests itself as maser emission which is of specific interest. Energy Levels of OH Diatomic molecules like OH have numerous energy levels as they not only have electronically excited levels, but they can also vibrate and rotate. Both rotation and vibration are quantized and give rise to the large number of levels. Because of the wealth of energy levels, OH can be observed at various wavelength in the optical, infrared and radio regime. - Source
Over on the RTL-SDR Facebook group (not affiliated with this blog), Job has described his experiment in more detail (link requires a Facebook account and membership). He writes:
As you may know or not...., I have been busy the last few weeks trying to detect maser W3(OH) with my 1.5-1.9 dish. The W3 complex lies in a darkened part of the Perseus galactic arm, at a distance of ∼2.2 kpc, and is one of the most intensively studied star-forming regions in the Milky Way Galaxy. Quite a challenge! It looks like I have a hit now after all.
Adjusting the Feed, calibrating the position of the dish and a lot of trial and error and a lot of patience seem to be leading to a result after all.... For now, I will keep this as my W3(OH) registration at 1665.405 MHz. Taking into account the Vlsr of currently 17 km/s (speed of earth and rotation around the sun), the final result comes close to the correct measurement. 1665.789 MHz = -32.22 km/s. Vlsr according to my calculations in terms of location and time is 17 km/s. -32-17=49 km/s. I think and hope that -49 km/s is the correct velocity of W3(OH) also considering the reasonably clear peak in the measured values in the graph.
These W3(OH) results were done with a special 1665 bandpass filter and 2 mini circuits lna/s. I will keep measuring for a while in the coming days, but soon I will switch back to another Feed over, namely the now under construction 611 MHz Feed with associated bandpass filter to once again 'capture' pulsar B0329+54. My ultimate goal with this dish!
I was very close last six months, but after extensive research with fellow radio amateurs we unfortunately could not confirm with 100% (!) certainty that the pulsar was detected at 1420 MHz with the 1.9 dish.
Also that research continues with longer exposure times and now research at 611 MHz, there is still some soldering and drilling and sawing to be done..... But first things first. Glad with this result anyway. Takes a lot of perseverance and patience.
Job's Radio Telescope detects Maser W3(OH).Job's Radio Telescope detects Maser W3(OH).
Over on YouTube Matt from the Tech Minds YouTube channel has put up a video demonstrating an open source program released on GitHub called "RTL SDR Scanner", or "rtl-sdr-scanner-cpp". This program is compatible with RTL-SDR and HackRF software defined radios, and allows users to record multiple analogue FM audio channels within the active bandwidth simultaneously.
To get a wider bandwidth, you can use a HackRF as your SDR, or you can also use multiple RTL-SDR dongles, or a device like the KrakenSDR which has multiple RTL-SDRs built into it. Alternatively, you can also have the software scan a much larger swath of bandwidth, however this could result in some transmissions being missed.
The audio is recorded as a wav file, and can be accessed through a web UI. We note that currently only FM recordings are supported but AM may be supported in the future.
RTL SDR Scanner - FULL Bandwidth Recording With WEB UI
In January we posted about the AntRunner, which is a $325 (incl. shipping) satellite antenna rotator shipped from China. Recently we've come across another low cost satellite rotator from Australia called the "SARCTRAC Mk3b" which was developed as part of a school amateur radio educational program. This rotator fully assembled comes in at AU$400 + AU$50 worldwide shipping (US$290 + US$40 = US$330), making it's price comparable with the AntRunner. SARCTRAC can be purchased from the sarcnet products page. Currently only the fully built unit is available, but in the future they plan to offer a cheaper kit option.
We're yet to test the SARCTRAC Mk3b, but based on an overall review of it's advertising, it appears that the SARCTRAC has some superior specifications and a superior design when compared to the AntRunner.
Unlike the AntRunner, SARCTRAC comes with all its components enclosed in a waterproof IP65 rated enclosure. Its design also makes use of a 3D position sensor with magnetometer, allowing the unit to know its orientation at all times, meaning that it should be able to automatically position itself from startup. The design also makes use of DC motors with a built in worm gear drive, so the the motors back driving is not possible.
The system is controlled via a built in Raspberry Pi 3B+ and can communicate with the controlling PC via WiFi. Raspberry Pi's have stable WiFi connections, so we shouldn't see the connection problems that we had with the ESP32 based AntRunner.
Just like the AntRunner, SARCTRAC is only a lightweight rotator with torque specs of 50kg.cm static and 25kg.cm dynamic. So it should be able to handle counterbalanced Yagi beams, and lightweight dish antennas.
The SARCTRAC Mk3b. An Australian designed and made light duty antenna rotator.
SARCTRAC Mk3 Satellite Antenna Rotator Controller and TRACker
Earlier in the month we posted about how rtl_433 has been ported to ESP32 devices that are combined with CC1101 or SC127X transceiver chips, such as the low cost LILYGO LoRa 32 boards available on Aliexpress.
Over on YouTube Matt from the Tech Minds channel has uploaded a video showing how to set up rtl_433 on an ESP32 device, and how to set it up with a home automation service like Home Assistant, Node Red or OpenHAB via an MQTT broker.
AirNav Systems are behind the RadarBox ADS-B tracking aggregator, one of several companies that use data obtained by volunteers running RTL-SDR dongles to collect ADS-B flight data from all over the world.
Recently they've launched a new project called ShipXplorer.com which is a marine AIS aggregation service. Like RadarBox, ShipXplorer relies on volunteers running receiver stations all around the world. AIS is an acronym for 'Automatic Identification System', and in a similar way to ADS-B on aircraft, AIS allows the real time tracking of marine vessel positions.
To help enthusiasts with AIS reception, AirNav have also launched an AIS optimized RTL-SDR dongle. At the moment we're not exactly sure how this dongle works, as it advertises NMEA output with no add-on programs required. So this may imply it has some onboard processing. But reviews imply that it is just an RTL-SDR dongle with TCXO. We are currently inquiring with AirNav Systems. UPDATE: We have clarified with AirNav and confirmed that the dongle is an RTL-SDR dongle with AIS modifications (LNA & TCXO). There is no onboard processing and the advertising text was an error.
AirNav Systems write:
Some great news on a new product we've been developing for the last year and that's just been released.
As you know our company has been in the industry for over 20 years, offering innovative and unique flight (RadarBox) tracking solutions. We supply multi-million USD companies with reliable/accurate worldwide real-time flight information and the RadarBox.com portal has now over 1.3 million accounts registered.
I'm reaching out to you to introduce you to AirNav System's ship tracker, ShipXplorer.com, which we launched a few months ago
About ShipXplorer.com:
ShipXplorer is a vessel tracking website that tracks global vessel movements in real time. ShipXplorer was developed to cater to the increasing navigational and tracking challenges faced by the maritime industry. In addition to offering professional maritime tracking solutions, the platform is also available for public use, with features and services specially developed for the burgeoning maritime enthusiast and vessel spotting community.
In addition to our recently launched ship tracking portal, we have a variety of AIS hardware, such as dongles and AIS antennas.
ShipXplorer AIS Dongle:
This high-performance dual channel AIS USB Receiver decodes AIS transmissions and enables the reception of AIS messages and data directly onto devices such as a Raspberry Pi or Laptop.
ShipXplorer AIS Optimized RTL-SDR Dongle
ShipXplorer AIS Antenna: ShipXplorer's omnidirectional AIS Antenna is optimized for long-range, dual channel (Channel A and B) 162 MHz VHF reception. It also ships with a 30 ft cable (SMA connector). Meant for outdoor use, this antenna is built with a fiberglass & aluminum alloy and can weather prolonged exposure to the elements.
ShipXplorer AIS Antenna
ShipXplorer Sea Range AIS Receiver:
SeaRange is ShipXplorer's newest 162 MHz, dual channel, AIS receiver. This brand-new model includes an added filter and an inbuilt amplifier designed to optimize AIS reception on both 162.025 MHz & 161.975 MHz frequencies.
And we are currently working on expanding our AIS coverage globally.
Researchers have discovered a way to transmit information wirelessly without power, simply by opening an closing a switch that connects a resistor to an antenna. This effect does not violate any physics - it works because the random thermal noise signature of the transmitter changes when the resistor is connected or disconnected.
The researchers used an RTL-SDR with high gain horn antenna and low noise amplifiers to measure changes in the thermal noise signature of the transmitter.
They also compare their idea to backscatter devices, which are another form of passive RF communications that make use of ambient radio signals such as from TV transmitters. They note that their thermal noise approach has a lower data rate and range compared to backscatter, but their next goal is to try and improve this.
Back in May 2016 we posted about Dejan Ornig, a then 26 year old student at the University of Maribor's Faculty of Criminal Justice, Slovenia who was almost imprisoned for using an RTL-SDR and finding a security flaw in Police TETRA communications. Dejan's story was one of the first of several stories we presented over the years involving a person getting into legal or political trouble from the use of SDRs like the RTL-SDR in more authoritarian countries.
TETRA is a RF digital voice and text communications protocol often used by authorities in European and other countries due to its ability to be secured via encryption. By using an RTL-SDR and an open source TETRA decoder, Dejan discovered that despite official documents specifying that all Police TETRA terminals must be authenticated (we assume this refers to encryption), none actually were.
Dejan went ahead and ethically reported his findings to the Slovenian authorities, working together with Police officers to disclose all his findings. However, in the end no action was taken, and Dejan took his findings to the press. It was then that Dejan was prosecuted by Slovenian Police, his house raided, and he discovered that Police had been collecting evidence against him for more than a year.
To complicate matters further it appears that Dejan also worked as an intelligence informant for the Police and was illegally instructed and helped by two Police detectives to hack into e-mails, Facebook profiles and other online communications of people deemed suspicious.
After seven years of court hearings, his case on the TETRA hack ended in 2022 with Dejan subjected to a seven month suspended prison sentence . Although suspension means that Dejan will not physically reside in jail, his record still records him as a criminal.
The criminal trial and conviction has led to Dejan having problems securing a job and moving forward with his life. He is currently asking for donations online in order to help get his life back on track. Dejan's full story can be read at the funding site. Alternatively you can donate via PayPal.
NOTE: As donation requests can often be scams, we have independently verified that it is indeed Dejan Ornig who submitted this story to us, and that the donation site and PayPal link is legitimate.
NOTE 2: In the past we have had issues moderating comments with stories involving transgender and female contributors. Dejan's story contains info about his sexual orientation and we will not accept derogatory comments on this site regarding this. If desired, please discuss the technical and legal nature of Dejan's situation, any other comments will be removed.
Today news has come out that ADS-B Exchange (ADSBx) founder Dan Streufert has sold ADSBx to a private firm called JETNET for (an estimated) $20 million. Dan was the sole owner of ADSBx, and after the sale he remains employed by JETNET. JETNET is a firm that provides aviation market intelligence to business customers.
UTICA, NY - JETNET, a leading provider of aviation data and market intelligence, announced today that it acquired ADS-B Exchange, one of the world’s largest networks of ADS-B/Mode S/MLAT feeders and providers of real-time and historical flight data. The acquisition is the second of what the company anticipates will be several future acquisitions as JETNET expands its data-driven product offerings for the aviation industry.
Founded in 2016 by Dan Streufert, ADS-B Exchange aggregates approximately 750,000 messages per second worldwide via receivers hosted by aviation enthusiasts around the world. The acquisition of ADS-B Exchange will enable JETNET to expand its flight data solutions with real-time information.
“ADS-B Exchange was founded as the go-to resource for aviation and flight-data enthusiasts,” said Dan Streufert, President and Founder of ADS-B Exchange. “Joining forces with JETNET is the perfect match as we look to meet the business needs of our users while maintaining our enthusiast roots and unfiltered data. With a long history of providing highly valuable data to the aviation industry, JETNET offers the resources we need to accelerate our growth.”
Like JETNET, ADS-B Exchange serves numerous constituents across the aviation industry, including Maintenance, Repair, Overhaul (MRO), airport operations, and aircraft leasing. In addition, its real-time data is used by dozens of commercial customers across numerous end markets, including aerospace & defense, government, research/academic, and financial services.
“We are committed to providing our customers with innovative product offerings which provide the information and intelligence they rely on to make critical business decisions,” said JETNET CEO Derek Swaim. “We’ve long admired ADS-B Exchange and know how strategic the company’s real-time data offerings are to the aviation industry. Dan has done an incredible job building a fast-growing business that customers love. We believe he, and the ADS-B Exchange platform, will bring significant value to our customers.”
About JETNET
As a leading provider of aviation market information, JETNET delivers comprehensive and reliable business aircraft research to its exclusive clientele of aviation professionals worldwide. JETNET is the ultimate source of information and intelligence on the worldwide business, commercial, and helicopter aircraft fleet and marketplace, comprising more than 110,000 airframes. Headquartered in its state-of-the-art facility in Utica, NY, JETNET offers comprehensive, user-friendly aircraft data via real-time internet access or regular updates. JETNET is a portfolio company of Silversmith Capital Partners.
ADSBExchange.com is an open source aggregator of ADS-B aircraft tracking data, contributed by volunteers who are all mostly running RTL-SDR radio dongles and Raspberry Pi based feeders. ADS-B data is transmitted at 1090 MHz and can be used to track aircraft movements.
Outrage over the sale has been expressed on Discord by various ADSBx open source co-developers who objected to the sale and appear to have received no compensation from the deal. The outrage has resulted in some co-developers actively encouraging that volunteer feeders remove their station from the ADSBx network. Several hundred of the over 9000 feeders have already disconnected their feeding stations, and the count is dropping (at the time of this post there were 9234 feeders).
Unlike similar ADS-B aggregators like FlightAware, FlightRadar24 and RadarBox, ADSBx is open source and promises to never censor the ADS-B data of billionaires, political leaders, military, police or other sensitive private aircraft. This has caused discussion over whether this free speech absolutist stance is either less or more moral. At the moment it is unclear if the acquisition will result in any ADSBx censorship policies changing.
Famously the @elonjet account (now @ElonJetNextDay) on Twitter used data from ADSBx. This account was used to automatically tweet out the location of Twitter owner Elon Musk's private jet in real time. The @elonjet account along with the @adsbexchange account was banned from Twitter shortly after Elon Musk's child had an altercation with a stalker. Legal action was threatened against @elonjet and "organizations who supported harm to [Elon Musk's] family" which could imply that ADSBx is in the legal action firing line.
While the sale may be discouraging to some, the project is still entirely open source, so it seems that only the branding and rights to the data collected have been sold. The following is entirely speculation on our behalf, but given that ADSBx was likely not very profitable and struggling to cover operating costs from donations only, and the threat of substantial legal action being taken against it's sole owner, the sale seems like the smart decision for the founder. We hope that the co-developers will receive some fair compensation as well.
ADS-B Exchange has been key to projects like "Dictator Alert" which tracks the real time location of the private jets of known dictators.
The Organized Crime and Corruption Reporting Project (OCCRP) has also made use of ADS-B Exchange data in the past to uncover the role that US civilian aircraft contractors are playing in the East African "kill chain".
Media have also used ADS-B Exchange to track the movements of the military aircraft like Black Hawk Helicopters and CBP Predator drones that were used to monitor crowds during the George Floyd protests.
