Over on YouTube Adam Alicajic 9A4QV (creator of the popular LNA4ALL) has uploaded a video showing a comparison of reception of Thuraya satellites with a LHCP (left hand circular polarization) and RHCP (right hand circular polarization) patch antennas. To receive Thuraya satellites, a LHCP antenna should be used, and Adam’s results show that using an antenna with the wrong polarization (RHCP) produces a signal that is as theoretically expected almost 20dB lower. Shortly after initially posting this Adam wrote in to comment on the following:
Thuraya LHCP original patch antenna have 2 patches stacked inside the panel antenna and the hand made RHCP patch antenna is made only of 1 patch. Theoretically, this should give the 3dB more gain for the Thuraya antenna.
The difference in the received signal due to polarization should be (theoretically) 20dB, thats RHCP vs. LHCP and I experience some 18dB of difference which is good result. Why not 20dB? First of all it is impossible to get 3dB more gain stacking the antennas, this is just the theory, more likely 2db in the practice.
To receive the signals Adam uses the patch antennas, which are connected to the MIX4ALL (a downconverter that he is currently developing), which is then connected to a RTL-SDR dongle.
In the first video Adam shows the difference the wrong polarization makes, and in the second he shows some information about the Thuraya LCHP antenna he uses.
Receiving Thuraya sat - LHCP and RHCP comparison using MIX4ALL
The SDRplay RSP is a $149 USD software defined radio that many consider as a next step upgrade from the RTL-SDR. See our recent review for a comparison between the Airspy, SDRplay RSP and HackRF.
One problem with the SDRplay RSP is that it comes in an unshielded plastic enclosure. This means that strong interfering signals can pass through the enclosure and cause interference, making any filtering done on the antenna less effective. Recently Tom Naumovski wrote in to us to let us know that he has been experimenting with a simple fix that involves shielding his RSP with adhesive copper tape. (Tom carefully notes that doing this may void the warranty). Tom simply wraps the plastic enclosure with conductive copper tape, making sure that electrical contact is made between the copper shielding and RSP ground (e.g. making sure the RSP USB and SMA ports make electrical contact with the copper tape)
Copper tape shielding for the RSP.
After shielding the RSP, Tom tested the shielding effectiveness by using his shielded RSP with no antenna connected to try and pick up an interfering tone transmitted by his HackRF SDR. He collected the results in a pdf file. The results clearly show that the shielded RSP does not pick up, or significantly reduces the power of the HackRF's interfering tone.
If you want to try this yourself, Tom writes that copper slug barrier tape found on eBay is the tape he used. Tom also points out the discussion on the Facebook SDRplay group thread he posted where other users have been using aluminium tape or alternative copper tape products.
Akos from the rtlsdr4everyone blog has come up with a new post that aims to help people avoid getting ripped off when trying to buy an RTL-SDR dongle. He shows that there are several sellers on eBay who sell branded products (like Nooelec and our own RTL-SDR Blog brand) for higher prices and higher shipping costs than the official manufacturer. He also notes that there are several sellers falsely advertising E4000 dongles, selling custom units that are too expensive and sellers that stuff in popular keywords to wrongly get to the top of rankings with an inflated price.
We’d like to add the following to Akos’ post: We believe these sellers offering our and other brands products at higher prices on marketplaces like eBay are simple market arbitrage bots that scrape items listed on Amazon and then list them on eBay for a higher price. They write that they can ship overseas, but they are simply using an address forwarder (like shipito, viabox or the eBay global shipping program) to forward the goods from the USA to overseas. Note that we ship overseas via our Chinese warehouse for free, so there is no need to use an address forwarder and pay high shipping costs.
We’d also like to note that we now have three companies who legitimately resell our dongle only units locally in the UK, Japan and in India. They may charge higher prices as they must contend with import costs and business taxes, but the advantage is fast local shipping and local support.
A few weeks ago Matthew Miller showed us how it was possible to run DSD+ in OSX using a program called Wineskin. Now he’s uploaded a new video that shows how to get SDR# working in OSX El Capitan with Mono. SDR# is designed to be used in Windows, but since it is written in C# under the .NET framework, it should be possible to run it on OSX with the open source Mono .NET implementation. The overall installation is not as straight forward as simply downloading a zip file like it is on Windows, but the tutorial Matthew provides is clear and easy to follow.
The steps involve downloading SDR#, downloading Mono, installing MacPorts, installing PortAudi, installing the RTL-SDR libraries and then setting up some required symbolic links. Finally he shows that to access the RTL-SDR you must first run RTL-TCP and then connect to that using the RTL-SDR (TCP) option in SDR#.
In the post Akos gives an overview of the features of each dongle, and runs tests on things like frequency drift and broadcast FM interference. He also runs SNR tests on Airband, low UHF, high UHF signals and shortwave frequencies. His tests show that the dongles with the R820T2 chip outperform the dongles with the R820T chip by about 4-5 dBs in SNR, and that the overall best dongle is our RTL-SDR Blog dongle.
Over on YouTube user Adam Alicajic (creator of the popular LNA4ALL low noise amplifier) has uploaded a video showing the performance of a home made wideband helix antenna that he has created for receiving signals such as ones from L-Band Inmarsat satellites. See our tutorial for more information on receiving Inmarsat signals.
Adams helix antenna is built out of an old used can and is based on a 1.1 turn design. In the first of three videos he shows that the SWR of the antenna is all well below 2.0 from 1.5 GHz to 3 GHz. In the second video Adam shows the performance of the helix antenna on actual L-band signals being received with an RTL-SDR dongle. In the final video Adam compares the helix again a patch antenna and finds that the two receive with very similar performance.
SimpliSafe is a home security system that relies on wireless radio communications between its various sensors and control panels. They claim that their system is installed in over 300,000 homes in North America. Unfortunately for SimpliSafe, earlier this week Dr. Andrew Zonenberg of IOActive Labs published an article showing how easy it is for an attacker to remotely disable their system. By using a logic analyser he was able to fairly easily reverse engineer enough of the protocol to discover which packets were the “PIN entered” packets. He then created a small electronic device out of a microcontroller that would passively listen for the PIN entered packet, save the packet into RAM, and then replay it on demand, disarming the alarm.
A few days later Micheal Ossmann (wireless security researcher and creator of the HackRF SDR and YardStick One) decided to have a go at this himself, using a YARD Stick One and a HackRF SDR. First he used the HackRF to record some packets to analyze the transmission. From the analysis he determined that the protocol was an Amplitude Shift Keying (ASK) encoded signal. With this and some other information he got from the recorded signal, he could then use his Yardstick One to instantly decode the raw symbols transmitted by the keypad and perform a replay attack if he wanted to.
Next, instead of doing a capture and replay attack like Andrew did, Micheal decided to take it further and actually decode the packets. This took him a few hours but it turned out to not be too difficult. Now he is able to recover the actual PIN number entered by a home owner from a distance without having to do any transmitting. With the right antenna someone could be gathering 100’s of PINs over a distance of many miles. Also, an expensive radio is not required, Micheal notes that the gathering of PIN numbers could just as easily be done on a cheap $10-$20 RTL-SDR dongle.
Micheal notes that the SimpliSafe alarm seems to lack even the most basic cryptographic protection, and that this is a problem that is seen all too often in wireless alarm systems. Rightly so, Micheal and Andrew are not publishing their code, although it seems that anyone with some basic knowledge could repeat their results.
The people behind this SDR are currently marketing SoDeRa as “the Arduino of the Telecom and Radio Engineer”. It appears to be designed mainly to implement IoT and other radio communications protocols, but it also sounds like it could find excellent use in the hobby and amateur market as well as have benefits for the average person. Interestingly, the developers also plan to implement an app store which would allow you to essentially download a radio and instantly configure the SoDeRa SDR for any desired protocol or application. They write:
This is the first time that a revolutionary device for which we are organising a joint crowd-funding campaign with Lime Microsystems is made public. The #SoDeRa is the cheapest software defined radio you can buy. The #SoDeRa will have an app store and will be able to provide any type of (bi-directional) radio communication going from LTE, Lora, WiFi, GPS, Bluetooth, radar, radio-controlled toys/robots/drone, digital radio, digital TV to even MRI scanners, satellite and air traffic communications by just installing an app. The #SoDeRa is the Arduino of the Telecom and Radio Engineer.
The SoDeRa is powerful enough to be a full MiMo LTE base station with long range coverage, provided you add the right antenna. You can via apps put other wireless communication protocols like LoRaWAN, Bluetooth, Zigbee, Z-Wave, GPS, Galileo, Airspace protocols, radar, MRI scanning RF, TV/Radio, any toy/robot/drone control, White Space, etc. But most importantly because of its price and ease of adding more protocols, the SoDeRa will enable anybody to define competing wireless communication protocols and put them into Github. Developers don’t like closed standards like LTE or complex standards like Bluetooth & Zigbee. The future will allow developers to compete against corporations and standardization bodies if they think current standards can be improved upon. The Internet has shown that this dynamic brought us easier standards through adoption like JSON and Yaml vs XML and EDI. Wireless, RF and telecom engineers never had an Arduino like the electronics engineers. The SoDeRa will plug this hole.
Development on SoDeRa is working towards a trend in radio systems where all radio devices are software defined, allowing for futuristic features like advanced spectrum control and the ability to change protocols on the fly. They write:
Including #SoDeRa in any type of smart device will greatly reduce the cost of deploying a mobile base station network because by open sourcing the hardware design it will become commodity. By including software defined radio in lots of devices, often with a completely different purpose, will allow these devices to become a smart cell via installing an extra app. In the future, support for software defined radio will likely be embedded directly in Intel and ARM chips. The foundational steps are already happening. This will likely reshape the telecom industry. Not only from a cost perspective but also from a perspective of who runs the network. Telecom operators that don’t deliver value will see their monopoly positions being put in danger. As soon as spectrum can be licensed on a per hour basis, just like any other resource in the cloud, any type of ad-hoc network can be setup. The question is not if but when. Open sourcing and crowdfunding will make that “when” be sooner than later. Smart operators that align with the innovators will win because they will get the app revenue, enormous cost reductions, sell surplus spectrum by the hour and lots of innovation. Other operators that don’t move or try to stop it will be disrupted. What do you want to be?
At first glance SoDeRa sounds like it will be an expensive device, but on their official website they are currently running a survey asking people what they would be willing to pay, and the lowest price given is $50 – $99. This makes it seem likely that in the future with enough volume SoDeRa could be sold at very low cost and become very popular.
I am willing to pay for 1 unit
$50 – $99 (lead time 9 months)
$100 – $199 (lead time 6 months)
$200 – $299 (lead time 3 months)
$300 – $399 (lead time 2 months)
$400 – $500 (lead time 1 month)
It sounds like the team behind SoDeRa are gearing up for a crowd funding campaign so we will be keeping an eye on this SDR.
Thanks to RTL-SDR.com reader Serdar (TA3AS) for submitting news about SoDeRa to us.
