Last year KD0CQ discovered that the SUP-2400 is a cheap $5 – $10 DirecTV (US satellite TV) module which can be hand modded into a downconverter for the RTL-SDR. A downconverter allows you to listen to frequencies above the maximum frequency range of the RTL-SDR by converting frequencies down into a range receivable by the RTL-SDR (or of course any other SDR). The modified SUP-2400 allows to you listen up to just over 4 GHz.
The SUP-2400 modification is moderately involved and requires soldering and desoldering SMD pieces, so this product is great for anyone who just wants a cheap and low cost downconverter which is ready to go. And at $25 USD it’s still very good value. Shipping within the USA is $7.75, and internationally it is about $13.50.
NooElec have just released their new NESDR Nano 3 RTL-SDR dongle for $27.95 USD. This is a new iteration in their line of ‘nano’ sized dongles, which are very small and suitable for use on small devices like Raspberry Pi’s and mobile phones. These nano form factor RTL-SDR dongles are also commonly used with the Stratux project which aims to bring lost cost ADS-B and UAT capabilities to small airplane pilots.
The Nano 3 appears to have a standard nano sized RTL-SDR PCB with TCXO inside, but comes with a new fully enclosed metal case with internal thermal coupling pads for cooling. A small external heatsink is also provided for optional use with the dongle. The dongle also uses a standard MCX connector, but the kit comes with an MCX to SMA F adapter. We’re not sure if the cooling from the small metal case will be enough to solve the L-band PLL lock problem, but perhaps when combined with the modified L-band driver tweak it might be enough. Failing that the external heatsink combined with slight airflow from a fan should be enough.
The previous model called the Nano 2, was also redesigned from the generic nano models for better cooling and to be able to use a TCXO. However, some tests by Chris of the Stratux project seem to show that the Nano 2 is quite a bit noisier than the cheaper generic nano dongles, and actually runs about 40 degrees F hotter. Noise is a problem with these small dongles as the noisy digital and switch mode sections are much closer to the RF sensitive parts. Heat is also an issue due to the lack of PCB space for heat dissipation. Hopefully the Nano 3 resolves these issues with the metal case and improved cooling.
There are now several generations and models of these ‘nano’ RTL-SDRs available. All briefly described below:
Two dongles for $40 USD with antennas, or two for $35 USD without antennas. We also wholesaled a few from them and sell them on our store for intl. buyers @ 16.95 USD each incl. shipping.
Redesigned for low power usage and less noise. Uses a switch mode power supply for less power wastage, but designed to be unaffected by any additional switch mode noise. Runs about 60 degrees F cooler than the Nano 2 and 16F cooler than the generic. Does not have an enclosure so is a bit more fragile. Also does not have a TCXO.
Good choice for Stratux or similar projects might struggle with the power requirements of multiple dongles on a Pi3. Doesn’t have a TCXO so mainly useful for frequency insensitive applications like ADS-B.
SDRPlay have just announced that their RSP1 unit has just been reduced in price to $99.95 USD. Their press release reads:
SDRplay are pleased to announce a price reduction for their entry-level SDR receiver, the RSP1 to $99.95 USD making it the most competitive mid-range SDR to include reception down to low frequencies without the need for an upconverter. The RSP1 provides general coverage receiver and panadapter capability from 10 kHz to 2 GHz. As well as providing SDRuno SDR software, support for popular 3rd party packages like HDSDR, SDR-Console and Cubic SDR is provided. Recent availability of an SD Card image makes for easy set up on a Raspberry Pi.
Over time we’ve seen the RSP1 reduce in price originally from $299 USD, to half price at $149 USD in March 2015 and then to $129 USD in September 2016, and now finally down to $99 USD. The newer RSP2 remains at a price of $169.95 USD.
Aerial TV is an Android app that allows you to watch DVB-T TV with an RTL-SDR on a mobile device. We posted about Aerial TV back in April and it was available on the Google Play store back then. Unfortunately Aerial TV has recently been banned from the Google Play store as apparently the app can be used to display copyrighted material from TV. The author writes the following on a Facebook post:
Google Play has suspended Aerial TV due to “[Aerial TV] claims to provide copyrighted contents from TV channels”. According to Google apps that display live TV are of “questionable nature”. I am trying to clarify what they mean. I would like to apologize to all affected users. If you have any concerns, feel free to get in touch with Google directly.
This is quite odd and probably a mistake. But if you are looking for Aerial TV it is now available on the Amazon app store with a current 35% discount. If you bought the app on the Google Play store then to get new updates you will need to uninstall it, contact the developer for a refund, and then purchase it again on the Amazon store. More info about that is available on the Facebook page. Updates about it’s availability will always be provided on the official website at aerialtv.eu.
During this years 2017 Hamvention convention I was invented by TAPR to present three talks about the RTL-SDR. Several people who watched the talks have requested the slides, so they are uploaded here in PDF format.
The HackRF is a $300 USD RX/TX capable software defined radio which has a wide tuning range from almost DC – 6 GHz, and wide bandwidths of up to 20 MHz. It uses an 8-bit ADC so reception quality is not great, but most people buy it for its TX and wide frequency/bandwidth capabilities.
Recently the HackRF received some negative press in the ‘Daily Mail’, a British tabloid newspaper famous for sensationalist articles. In the article the Daily Mail show that the HackRF can be used to break into £100,000 Range Rover car in less than two minutes. The exact method of attack isn’t revealed, but we assume they did some sort of simple replay attack. What they probably did is take the car key far away out of reception range from the car, record a key press using the HackRF, and then replay that key press close to the car with the HackRF’s TX function. Taking the key out of reception range of the car prevents the car from invalidating the rolling code when the key is pressed.
Of course in real life an attacker would need to be more sophisticated as they most likely wouldn’t have access to the keyfob, and in that case they would most likely perform a jam-record-replay attack as we’ve seen with cheap homemade devices like RollJam. The HackRF cannot do this by itself because it is only half-duplex and so cannot TX and RX at the same time.
We should also mention that the HackRF is not the only device that can be used for replay attacks – potentially any radio that can transmit at the keyfob frequency could be used. Even a very cheap Arduino with ISM band RF module can be used for the same purpose.
Thanks to Michael Rahaim a Postdoctoral Researcher at Boston University for letting us know about the New England Workshop for SDR (NEWSDR) which will be held on June 1 & 2 and Tufts University in Medford, MA. They write:
A few of my colleagues and I are organizing the New England Workshop for SDR (NEWSDR) next month and we are currently accepting submissions for poster presentations. The event will be held at Tufts University and is sponsored by MathWorks, Ettus/NI, MediaTek and Analog Devices. It is the 7th time we’ve held the workshop and we typically have attendance of 80-100 people from industry, academia, and government.
This seems to be mostly an academic and industry conference type event, but a few people reading this blog may be interested. Registration is free.
This year as well as the poster presentations there will be a tutorial and introduction to using the PlutoSDR, which is an (as of yet unreleased) TX & RX capable SDR that will be priced at around $149 USD. It looks to be like a way to get started with SDR TXing very cheaply. During the workshops they are also providing tutorials on using USRP SDR devices with MATLAB Simulink, and with FPGAs. In 2016 they also had some interesting presentations including “Wireless Beyond RF: From Underwater to Intra-body Ultrasonic Software Defined Radios” and a tutorial on “Identifying Mystery Waveform Using Simulink and RTL-SDR”
Over on our store we now have a limited amount of “Low Power V2” RTL-SDR dongles available for sale for $16.95 USD incl. free international shipping. These are dongles that were produced for the Stratux project which aims to provide a very low cost ADS-B and UAT receiver for small airplane pilots. These Stratux kits typically consist of a Raspberry Pi, two nano RTL-SDR dongles, a GPS dongle and a Android or iOS tablet. The two RTL-SDR dongles receive both 1090 MHz ADS-B and 978 MHz UAT which are decoded on the Raspberry Pi. The Raspberry Pi then sends the decoded aircraft position and weather data to the tablet via WiFi which is running commercial navigation software.
One issue that Stratux users continually run into, is that the Raspberry Pi is sometimes unable to power two or more RTL-SDR dongles. When running a Pi with two RTL-SDR dongles, a GPS dongle, and cooling fan the total power draw is above 1A which can cause power supply problems and glitching. By using a low power RTL-SDR these problems can be avoided by keeping the total current draw under 1A.
The Low Power V2 Stratux RTL-SDR’s draw about 160-170 mA, whereas standard dongles draw about 260 mA, so that’s a saving of almost 100 mA. On battery power this current saving can mean a few hours more of operation. The Low Power RTL-SDR dongle achieves its lower current consumption by using a switch mode power supply instead of a linear regulator which is commonly used on most other RTL-SDR dongles. The trade off is that switch mode supplies are inherently RF noisy, so increased noise can be seen on the spectrum. Despite the increased noise, most applications like ADS-B are not significantly degraded. We have seen switch mode supplies used on some other RTL2832U dongles sold in the HDTV market as well. For example all the R828D based DVB-T2 dongles that we have seen use switch mode supplies as well, and also draw about 170 mA.
We think that these low power RTL-SDRs could be useful in other non-stratux related applications too. For example, they could be used on mobile Android devices. One of the key problems with Android usage is that RTL-SDR dongles tend to drain the battery quickly. They could also be used on solar and battery powered installations to help achieve longer run times. Or like with Stratux they could be used on a Raspberry Pi running other applications, to ensure that multiple dongles can be attached.
Currently we are selling these dongles for $16.95 USD with free international shipping included. Note that these dongles do not come with an enclosure (just a bare PCB), and they do not have a TCXO. Below is more information about these dongles.
Back in November 2016 we posted a review on the Low Power V1 dongles. Since then Chris (the man behind producing these dongles) has brought out the Low Power V2 models which improves upon V1 significantly. By switching to a 4-layer PCB the dongle is now much quieter in terms of RF noise produced from the switch mode power supply, and it also now runs significantly cooler. The dongle also now uses even less power and is more sensitive compared with V1.
In terms of heat produced and power used, the NESDR Nano 2 is the hottest and most power hungry, followed by the Generic Nano, the Low Power V1 and then the Low Power V2. For comparison the NESDR Nano 2 draws 1.362W of power, the generic nano 1.318W, the Low Power V1 1.003W, and the new Low Power V2 draws only 0.933W.