Outernet’s Old Antenna Stock for Sale: L-Band Active and Filtered Ceramic Patch Antennas

In the past the Outernet project operated on L-band frequencies, and for the service they manufactured a number of active L-band active ceramic patch antennas for use with RTL-SDR dongles. Outernet has since moved on to faster Ku-band delivery, and hence their old L-band antennas can no longer be used for their service.  There are a few of these patch antennas left over in Outernet's stock and they are currently selling them on eBay for US $29 + shipping (link expired).

Although no longer useful for Outernet, these antennas are still very useful for receiving other L-band services such as STD-C SafetyNET and AERO. SafetyNET is a text broadcast intended for sailors at sea, but contains many interesting and potentially useful messages for others too. Often they transmit data like military sea live firing warnings, reports of marine pirate activity, search and rescue reports, scientific vessel reports as well as weather reports. AERO is the satellite version of ACARS, and is used by aircraft to communicate with text messages to and from ground stations. L-Band AERO signals only contain information from the ground station up to the aircraft. For air to ground you'll need a C-band receiver set up. AERO is the satellite communications protocol that was so heavily centered on during the MH370 flight disappearance investigation.

In the past we've reviewed the Outernet L-band ceramic patch and found it to work very well. Certainly STD-C and AERO signals are easy to receive with the antenna if you point it at the satellite. The antenna requires bias tee power and can easily be used in combination with the bias tee on our RTL-SDR V3 dongles. The onboard filter helps reduce problems from interfering signals, but restricts reception to 1525 - 1559 MHz, so Iridium signals cannot be received with this antenna.

The L-Band Active Ceramic Patch Antenna.
The L-Band Active and Filtered Ceramic Patch Antenna.

Hacker Warehouse Demonstrates Pager Decoding with an RTL-SDR

Over on YouTube the web show Hacker Warehouse have created a video explaining wireless pagers and how RTL-SDRs can be used to sniff them. In the video host Troy Brown starts by explaining what pagers are and how they work, and then he shows how to decode them with SDR# and PDW. We have a tutorial on this project available here too.

Later in the video he shows some examples of pager messages that he's received. He shows censored messages such as hospital patient data being transmitted in plain text, sports scores, a memo from a .gov address claiming allegations of abuse from a client, office gossip about a hookup, a message about a drunk man with a knife, a message from a Windows server with IP address and URL, a message from a computer database, and messages from banks.

In the past we've also seen an art installation in New York which used SDR to highlight the blatant breach of privacy that these pager messages can contain.

Decoding Pager Data with RTLSDR - Tradecraft

Warning: Stolen SDRplay RSP-1A’s on eBay will not Function Properly

SDRplay have recently released a PSA noting that a consignment of RSP-1A's was stolen from their manufacturing partner. This is important as SDRplay have decided to blacklist the serial numbers from this stolen consignment, and so the stolen units will not work at all, or may only work with a small number of programs. You may then be stuck trying to obtain a refund from the thief, although we believe that SDRplay would most likely help get you a legit device if you purchased a stolen one unknowingly. They write:

It has come to our attention that a consignment of RSPs that was recently stolen from our manufacturing partner have appeared for sale on eBay.

If you have any of the following devices and have purchased them from a non-approved reseller of SDRplay products, please contact [email protected] and also contact the seller requesting a refund as the devices appear to have come from a stolen consignment of goods.

Please be aware that we have now black-listed the above serial numbers [see the original forum post for black list serials] and these devices will not work at all or will only work with a very restricted range of software. Anyone with any of these devices will not receive any form of support or technical assistance from SDRplay.

We are aware that the following eBay sellers have been selling devices from the stolen consignment:

https://www.ebay.co.uk/usr/greenfields1001 (formerly listed as mansnothot01)
https://www.ebay.co.uk/usr/connie68purple

Whilst we recognise that the above resellers may well have purchased the devices in good faith and in complete innocence, they have thus far failed to cooperate with us by explaining where they obtained the devices from. We will therefore be forwarding on their details to the Police so that they can investigate further.

We strongly recommend that people only purchase new devices from an authorised SDRplay distributor or reseller. A full list of authorised sellers is available from our website at:

https://www.sdrplay.com/distis.php

Thank you

Admin – SDRplay Ltd

It is a good time to also remind that there are many scam sellers on eBay. There are often fake listings for RTL-SDR dongles too, with scammers selling our RTL-SDR V3 for $10. These are simply fake listings and not stolen products. Those sellers rely on baiting people into purchasing at the lower price, and then they simply take the money and run. Normally PayPal or eBay will eventually refund you, but the dispute process could take several months. The real eBay account for our RTL-SDR products is "rtl-sdr-blog". 

Update: SDRplay released a second statement just now mentioning why the blacklist was undertaken.

Further to our previous post on this matter, what people will not yet be aware of is that we also had a consignment of the new product that is due to be announced tomorrow stolen. We have had three separate consignments stolen and devices from all three have turned up on the same ebay account and so this suggests that a single person is responsible for all three thefts.

The decision to blacklist devices was taken to target the as of yet unsold devices to render them worthless and to make it pointless for the thieves to attempt to sell them. Of the consignment of RSP1As and RSP2pros, we have reason to believe that the majority remain unsold and so we took this action to render them worthless and deter the thieves from attempting to sell them.

By making this public in the way we did, we are giving the following messages:

1. We have end to end traceability of our products from the point of manufacture to the point that they reach our seller. If any are stolen, we will know and we will know the serial numbers of the devices taken.

2. Via the serial numbers we can render these devices worthless and so there is no point in attempting to sell them. The unwitting purchaser will become aware that they have received a stolen device and will want their money back.

3. Because we can make these devices worthless, there is no point in stealing any more of our products.

We made public the serial numbers of the RSP1As and RSP2Pros public and very clearly asked anyone who may have purchased one of these devices (believing them to be genuine) to contact us. Those that do and assist us in tracking down the thieves will be treated VERY sympathetically.

We will NOT penalise innocent people so that assumption that this is our intent is frankly WRONG!!

Our objective here is to gather as much information as possible so that it can be forwarded to the relevant law enforcement agencies to assist them in tracking down the culprits.

Some of the comments that we have seen on this subject by ill-informed people are massively wide of the mark. We have a responsibility to gather as much information as possible and forward it to the relevant authorities. We have also suffered a considerable financial loss, not just in terms of the cost of the goods, but also in terms of the lost sale opportunities. Some of the comments that we have seen regarding insurance cover are equally ill informed. For insurance claims to be taken seriously, you have an obligation to report the thefts and take all possible steps to assist in the recovery of the stolen goods that that is precisely what we are doing.

Finally, we have NEVER said that we will "brick" the devices. That is an incorrect assumption that has been made. Blacklisting and 'bricking' are two quite different things.

Building A Low Cost GOES Weather Satellite Receiver with an RTL-SDR

Over on Twitter and his github.io page, Pieter Noordhuis (@pnoordhuis) has shared details about his low cost RTL-SDR based GOES satellite receiving setup. GOES 15/16/17 are geosynchronous weather satellites that beam back high resolution weather images and data. In particular they send beautiful high resolution 'full disk' images which show one side of the entire earth. As the satellites are in geosynchronous orbit, they are quite a bit further away from the earth. So compared to the more easily receivable low earth orbit satellites such as the NOAA APT and Meteor M2 LRPT satellites, a dish antenna, good LNA and possibly a filter is required to receive them. However fortunately, as they are in a geosynchronous orbit, the satellite is in the same position in the sky all the time, so no tracking hardware is required.

In the past we've seen people receive these images with higher end SDRs like the Airspy and SDRplay. However, Pieter has shown that it is possible to receive these images on a budget. He uses an RTL-SDR, a 1.9 GHz grid dish antenna from L-Com, a Raspberry Pi 2, the NooElec 'SAWBird' LNA, and an additional SPF5189Z based LNA. The SAWBird is a yet to be released product from NooElec. It is similar to their 1.5 GHz Inmarsat LNA, but with a different SAW filter designed for 1.7 GHz GOES satellites. The total cost of all required parts should be less than US $200 (excluding any shipping costs).

Pieter also notes that he uses the stock 1.9 GHz feed on the L-com antenna, and that it appears to work fine for the 1.7 GHz GOES satellite frequency. With this dish he is able to receive all three GOES satellites at his location with the lowest being at 25 degrees elevation. If the elevation is lower at your location he mentions that a larger dish may be required. It may be possible to extend the 1.9 GHz L-Band dish for better reception with panels from a second cheaper 2.4 GHz grid dish, and this is what @scott23192 did in his setup.

For software Pieter uses the open source goestools software that Pieter himself developed. The software is capable of running on the Raspberry Pi 2 and demodulating and decoding the signal, and then fully assembling the decoded signal into files and images.

Pieters GOES RTL-SDR Receiving Setup
Pieters Low Cost GOES RTL-SDR Receiving Setup

Detecting GPS Jammers In Augmented Reality

The NT1065 is an all-in-one 4-channel global navigation satellite system (GNSS) receiver chip. It is highly versatile and can receive and decode multiple navigation satellites such as GPS, GLONASS, Galileo, BeiDou, IRNSS and QZSS. Being able to receive so many satellites, it is capable of centimeter level positioning.

The team at Amungo Navigation have taken this chip and have created a product called the NUT4NT+ which is essentially a development board for the NT1065, and all the software for signal processing with it is provided as open source software. In the near future they are planning to begin fundraising for the product over on the crowd funding site CrowdSupply.

One very interesting application that they have been developing with a device similar to the NUT5NT+ is a GPS Jammer/Spoofer detector system which they call the Amungo XNZR. This is a combined 4-channel GNSS receiver and 4-antenna GNSS antenna system built into a small package that fits onto the back of an Android tablet. When connected to the software it uses augmented reality (AR) to show you exactly where GPS jammers are in the vicinity by using coherent signal processing. If you're not familiar with AR, this is the technique of overlaying digital data/images on top of a live real world camera view.

Detecting a Kremlin GPS Spoofer in Augmented Reality
Detecting a Kremlin GPS Spoofer in Augmented Reality

In the video below they take their XNZR detector to Varvarka Street in Moscow Russia and determine the location of a GPS spoofer in the vicinity. 

More information about their product can be found on their homepage, and on various interesting forum posts by someone from the company that detail some of their experiments. Note that the forum posts are in Russian, but Google Translate can be used to translate the text.

XNZR is searching for Moscow GPS Spoofing Anomaly

Video Comparing the RSP-1A Against the Airspy HF+, and Testing out the Airspy HF+ R3 Mod

Over on YouTube icholakov has uploaded two new comparison videos. The first compares the Airspy HF+ against an RSP-1A on HF signals with a W6LVP receive loop antenna in a noisy suburban backyard in Florida.

Results appear to be quite similar for most signals, although we noted better performance from the HF+ on some particular weak signals surrounded by strong AM stations in the test such as the 810 kHz signal at 3:37, but lower noise on some signals received by the RSP-1A such as at 9:32. The tests were performed with a stock HF+ without any firmware updates applied so it's possible that the updates could improve results further.

In the second video icholakov performs the R3 mod on his Airspy HF+ and compares the results before and after. It appears that shorting R3 improves reception on MW slightly, and has little effect at higher frequencies. We also note that the R3 mod is mostly designed to mostly improve VLF/LF reception which is not tested in the video.

W6LVP receiving loop: Airspy HF+ vs. SDRPlay RSP-1A

Airspy HF+ R3 Modification test

Demonstrating Two Channel Coherent Spatial Filtering In a GNU Radio Simulation

Over on YouTube VE6EY has uploaded a video that demonstrates spatial filtering (aka beamforming) working in a GNU Radio simulation. This is a technique that can be used with a 2-channel coherent SDR with to nullify local interference. One SDR is connected to an antenna for receiving the distant signal, and the second is connected to a noise probe that is designed to receive only the local noise source.

The demonstration is not performed with real SDRs, but with prerecorded signals, although it still shows the effectiveness of the technique. In the video VE6EY shows switch mode and powerline noise being nulled out from some AM music, and explains through a demo why phase coherence is required.

V36EY gives further information and a link to download the demo over on his blog post.

SDR Spatial Filtering Demo

A Review of the miniVNA Pro Vector Network Analyzer

Over on YouTube Kevin Loughin has reviewed the miniVNA Pro Vector Network Analyzer (VNA). A VNA is a tool that can be used to measure antenna or coax parameters such as SWR, impedance, loss as well as characterize filters. It is a very useful tool to have if you are building antennas, filters or RF circuits. The RTL-SDR with a noise source can somewhat be used as a network analyzer, but a fully functional VNA will be a lot more accurate and easier to use. The miniVNA costs US$490 and is significantly cheaper compared to desktop based VNAs.

In the video Kevin explains what a VNA is and that the miniVNA Pro is, shows how to calibrate the unit, shows some measurements on his roof mounted dipole, measures a home made filter, and then demonstrates portable operation of the device on an Android phone. The miniVNA Pro has a built in battery so it can be used portably in the field together with an Android phone and bluetooth.

We ourselves have the miniVNA tiny which operates in frequency from 1 MHz all the way up to 3 GHz, whereas the miniVNA Pro operates from 0.1 MHz to 200 MHz. However the tiny does not have portable operation. The miniVNA tiny is excellent for building things like ADS-B and Inmarsat antennas.

The miniVNA Pro and Tiny can both be found for sale on Ham Radio Outlet.

Ham Radio - A look at the miniVNA PRO Vector Network Analyzer