SDRPlay RSP2 Release Announcement and Review

Today SDRplay have just released their newest software defined radio – the Radio Spectrum Processor 2 (RSP2) which is the successor of the RSP1. The RSP2 costs $169.95 USD, and the older RSP1 is still for sale at $129.95 USD. There is also the “RSP2pro” model which is an RSP2 in a metal enclosure, and this sells for $192.95 USD.

The RSP2 has nearly the same base specifications as the RSP1 (12 bit ADC, 10 MHz bandwidth, 10 kHz – 2 GHz range), but now comes with additional features and enhancements such as a software switchable BCFM and BCAM notch filter, TCXO, multiple antenna ports, HF optimized Hi-Z antenna port, clock in and out ports, better shielding and can also now tune down to 1 kHz.

It is available for purchase at sdrplay.com/rsp2 (Worldwide), HamRadioOutlet.com (USA) and ML&S (UK).

The announcement reads:

SDRplay Limited has today announced the launch of a second Software Defined Radio product – the RSP2.

Building on the popularity of our first product, the RSP1, we have now launched the RSP2. The RSP2 delivers a significant number of additional features which result in a higher spec for specialist amateur radio users as well as benefits for additional scientific, educational and industrial SDR applications.

Here are the main additional features of the RSP2:

  • 10 built in front-end pre-selection filters, with substantially enhanced selectivity
  • Frequency coverage extended down to 1 KHz
  • Software selectable variable gain Low Noise Preamplifier
  • 2 x SMA Software Selectable 50Ω RF ports (1.5 MHz – 2 GHz)
  • 1 x High Impedance RF port (1 kHz – 30 MHz)
  • Built in software selectable MW /FM notch filters
  • Highly stable 0.5PPM TCXO trimmable to 0.01PPM
  • 24MHz Reference clock input / output connections
  • 4.7V Bias-T option (on one of the software selectable antenna inputs)
  • RF screening within a strong plastic case for the standard RSP2
  • A Rugged metal box version – the ‘RSP2pro’

When used together SDRplay’s own SDRuno software, the RSP2 becomes a high performance SDR platform. The benefits of using the RSP2 with SDRuno include:

  • Highly integrated native support for the RSP2 professional grade software based upon class leading ‘Studio 1’, free of charge
  • Calibrated S-Meter including support for IARU S-Meter Standard
  • Calibrated RF Power Meter with in excess of 100 dB of usable range
  • Best in class audio quality

Currently the RSP2 requires the use of SDRuno software, but in the coming weeks we plan to provide support for HDSDR, Gnu Radio, CubicSDR and we are working with Simon Brown to get support within SDR Console.

We believe that the RSP1 will continue to prove very popular as the lowest cost 12-bit SDR for general applications such as Short Wave Listening or for use as a panadapter and we pleased that we can now offer more choice to the growing community of RSP users.

The RSP2 is expected to retail at approximately £130 (excluding taxes) or $169 (excluding taxes)

For more information visit our website on www.sdrplay.com

The new RSP2
The new RSP2

The table below shows a comparison of the RSP1, RSP2 and RSP2pro. A datasheet can be found on SDRplay’s new RSP2 webpage.

Differences between the RSP1, RSP2 and RSP2pro.
Differences between the RSP1, RSP2 and RSP2pro.

Introducing the SDRplay RSP2 (AV013)

SDRplay RSP2 Review

Two other reviews have already come out, one from swling.com and one from NN4F.com.

Thanks to the generosity of the SDRplay team we were fortunate enough to receive an early pre-production review model of the standard (not pro) RSP2 unit. The unit arrived a few days ago, and here we give it an initial review. In a previous review we did a comparison of the Airspy SDR, SDRplay RSP1 and HackRF. We found that the RSP1 and Airspy had similar overall performance, but that the Airspy would be better for those people who needed high dynamic range performance in strong signal environments, and that the SDRplay RSP1 would be best for people who wanted a low cost all-in-one unit with performance better than an RTL-SDR. 

The Inside

We decided to take a look inside and see how much the PCB has changed from the RSP1 to the RSP2. Judging from the two photos we can see that there is quite a significant increase in the number of components used. What was once a sparse PCB is now populated much more heavily with additional filter banks and several new switches. However, the core design of the RSP2 remains similar to the RSP1. The RSP2 uses the same Mirics MSi001 tuner chip and MSi2500 ADC chips.

The standard plastic enclosure is also now spray painted on the inside with conductive metal paint which helps by acting as a Faraday cage. This prevents interference from getting through and should be almost as good as a metal enclosure.

The conductive paint seems to be working well, as in our tests the RSP2 does not receive any signals with the antenna disconnected, whereas the RSP1 does weakly receive some very strong pager signals.

RSP1 & RSP2 PCBs
RSP1 & RSP2 PCBs
Conductive paint on the plastic case inside.
Conductive paint on the plastic case inside.

Continue reading for the rest of our review

Continue reading →

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The 2016 /r/rtlsdr Reddit Giveaway

The mods of the /r/RTL-SDR community on the Reddit discussion platform are currently hosting an RTL-SDR themed giveaway. The prizes up for grabs include units which have been donated from ThumbNet (Nongles.com) and us at RTL-SDR.com. The prizes also include several donated home brew projects including filters and downconverters. See the table at the end of this post for the full prize list.

To enter all you need to do is write a comment on the competition thread at reddit.com/r/rtlsdr and mention what you like about SDR and what you hope to do with a prize if you win. While you’re at it we strongly suggest subscribing to /r/rtlsdr if you haven’t already as that is one of the the largest and most active communities of rtlsdr users on the web.

The competition closes on December 3rd and only one entry per household is allowed.

Place Prizes Description
1st-2nd 2 ThumbNet – Nongles.com N3 SDR RECEIVER
3rd-5th 3 RTL-SDR Blog V3 Dongle + Antenna Kit
6th-7th 2 $25 ThumbNet – Nongles.com Gift Certificate
8th-11th 4 RTL-SDR.com Blog V3 Dongle Only
12th 1 PA0RDT Mini-Whip Antenna
13th-14th 2 RTL-SDR.com Blog Broadcast FM Filter
15th-16th 2 Up to ~4.5GHz Microwave Downconverter
17th 1 70cm HamSat / 433 Combline BPF
18th-20th 3 Choice of Custom Made 5 Pole HF BPF/LPF/HPF
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Two Videos That Show How To Set Up An Outernet Receiver

Outernet is a relatively new satellite based file delivery service which can be received with an RTL-SDR dongle. They continuously send out useful data like weather reports, news, APRS data as well as files like Wikipeda pages, images, videos and books. Previously we posted a tutorial that shows how to set up an Outernet receiver here.

If you instead prefer video tutorials, then two YouTube channels have uploaded Outernet set up tutorials. The first tutorial is by MKme Lab. In this video they set up Outernet using a Raspberry Pi and a Lipo battery for portable operation. Once setup he shows the Outernet browser and weather app in action.

DIY Raspberry Pi Outernet Satellite Receiver Assembly & Testing | #EduCase Project Build

The second video is by John’s DIY Playground and is similar, but goes a bit deeper into setting up the software on the Raspberry Pi and shows how to point the patch antenna towards the satellite.

Outernet satellite receiver using Raspberry Pi

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An RTL-SDR Receiver App Written in Swift for MacOS

Over on YouTube user GetOffMyHack has uploaded a video that shows his development of a Mac based general purpose tuning app for the RTL-SDR, which was written in the Swift programming language. Swift is a programming language which is designed for creating apps for a wide range of smart Apple devices.

GetOffMyHack’s program currently has a spectrum and waterfall view, can tune to any frequency, demodulate NFM and AM, and it also has a built in CTCSS decoder. At the moment the software and code is unreleased, but he writes that in the future the code will be released and made open source once he reaches the next version in the development cycle. Keep an eye on his YouTube channel for any updates.

MacOS Desktop RTLSDR Application written in Swift

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A Portable RTL-SDR Project

Frequent RTL-SDR.com reader Rodolfo recently wrote in to us wanting to share a portable RTL-SDR set up that he has produced. From the supplied photo the portable unit looks very robust and really well built. We hope that it will give inspiration to others wanting to make portable units as well. Rodolfo wrote:

Last year, a friend of mine in the telecommunication services industry, was talking to me regarding some kind of sporadic interferences he was getting in their devices, and asked if I can do something about it. I spend some days trying to figure a way to help him, as it was (and is) a good friend of mine. I seat in my library at home, and start to scratch some designs, based in rtl-sdr.com article published in 6 October 2014: “RASPBERRY PI RTL-SDR SPECTRUM ANALYSER SCANNER”. Some weeks later, I get the designs and get a good cup of coffee with him. After the second cup,  and I get a “go” sign, and so it born a portable spectrum capture that I called “sapinho”, as my youngest son nickname. Just “for the record”, “sapinho” in Portuguese means a little frog – you can jump from place to place to scan the RF band.

So, the device is very simple, the great problem was  finding the most small configuration possible, to meet the portable specifications:

  • Raspberry pi ver. B;
  • NooElec RTL Receiver;
  • “FreqShow” python software.
  • A pair of LM2596 DC-DC;
  • 3.5 ‘’ TFT LCD Touch Screen for Raspberry Pi;
  • 6VDc battery;
  • Cable;
  • Expandable antenna;
  • Enthusiasm.

Trying to get the most of it, I put a wifi dongle, so that he can connect to a nearby hotspot, or get a “had oc” connection for remote control. There is a plug for charging the batteries, and two red leds (one for the charging , and the other for operation status).  All of it was install in a 100 x 300 x 100 (mm) portable aluminum box.

Portable RTL-SDR Unit
Portable RTL-SDR Unit
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New Low Power RTL-SDR’s for Stratux ADS-B Receivers

Stratux is an RTL-SDR based project that gives small plane pilots access to ADS-B data, without having to purchase an expensive commercial ADS-B installation. It consists of software that runs on a Raspberry Pi, and two RTL-SDR dongles to receive both 1090 MHZ ADS-B, and 978 MHz UAT. The decoded data is then streamed via WiFi to a tablet running navigation aide software with charts for pilots.

Typically Stratux kits come with two standard ‘Nano’ styled RTL-SDR dongles. However, users of the Stratux system have been reporting problems with overheating, and with the Pi struggling with the high current demands of a typical setup which includes two RTL-SDR dongles, active WiFi broadcasting, a GPS unit and an optional cooling fan. A typical RTL-SDR dongle draws 280 mA, so two dongles are already pulling 560 mA.

Chris, creator of the Stratux software and seller of Stratux kits has just released a new low power RTL-SDR dongle (kit with antennas). The cost is $35 USD for two dongles (one for 1090 MHz and one for 978 MHz). The dongle obtains its low power feature by using a switching regulator instead of a linear regulator as the main 3.3V power regulator on the PCB. Normally you would not want to use switching regulator for the main regulator in an RF device because they are very noisy in terms of RF interference generated. However switching regulators are much more efficient compared to linear regulators, and thus save a lot of current wastage. Other dongle manufacturers like ThumbNet have actually gone the other way, removing the secondary 1.2V switching regulator from the standard dongle design, and using a linear regulator instead. The ThumbNets end up with lower noise, but draw 400 mA of current. 

With the switching regulator the new Stratux dongles only draw about 185 mA, a saving of almost 100 mA. They also generate 0.5W less heat. Users of the Stratux system have so far been impressed with them and have not noticed any appreciable difference in ADS-B performance. We think that these low power dongles might also be of interest to people using them on mobile phones or battery/solar powered remote installations.

The new Stratux low power RTL-SDR dongles.
The new Stratux low power RTL-SDR dongles.

During testing, Chris found that there was no significant noise floor increase visible on the 978 MHz  & 1090 MHz frequencies. Most of the switching noise increase appears to be on the lower frequencies, but those frequencies are not relevant for the Stratux use case anyway.

Chris was kind enough to send us some samples of the new low power dongles. First we ran a noise floor scan with rtl_power to determine the effect of the switching regulator. The results show that the spurs and noise floor readings have definitely increased by a significant amount, with an especially large noise floor rise below 400 MHz. In SDR# wandering switching noise spurs are also visible throughout the spectrum, but they tend to weaken in strength once an antenna is connected.

Stratux vs Standard Dongle vs V3 Dongle Noise Floor Scan
Stratux vs Standard Dongle vs V3 Dongle Noise Floor Scan

Fortunately, ADS-B is very tolerant to spurs and is generally not affected by this type of noise. We’ve only given the Stratux a quick test on ADS-B so far, but when compared against another ‘nano’ styled dongle the Stratux performed nearly identically (in fact even a little better) in terms of messages received. The two dongles were connected to the same antenna via a splitter and we logged the number of messages received in 10 minutes.

Quick ADS-B Reception Test
Quick ADS-B Reception Test

In conclusion the Stratux RTL-SDR set out to solve the mobile power issues suffered by people using the Stratux system. It has achieved that with an over 100mA saving in current use. The new Stratux dongle is much noisier, but the noise does not appear to significantly affect ADS-B reception as seen by our results and from the reports from Stratux users who beta tested this dongle.

Chris has also created a post on Reddit /r/stratux which talks a bit more about the new dongle.

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Real Time RTL-SDR Passive Radar with Clutter Supression and Target Acquisition

Marcus Herber is a 4th year electrical engineering student at the University of Queensland, Australia. For his final year thesis he set out to build a real time RTL-SDR based passive radar with clutter suppression and automatic target acquisition. On YouTube he’s uploaded a video that gives a quick overview and demonstration of his project. The description reads:

For my final year electrical engineering thesis, I developed a real-time passive radar system with clutter suppression and target acquisition. This was mainly able to be achieved through the use of GPU computing, with CUDA. With any slight improvement of the following hardware (especially the GPU), the system would be able to perform much faster, and increase the number of frames per second. Choosing a slightly better GPU would also allow for a better SDR, with a faster sampling rate.

All the signal processing and the algorithm was done in Python 3, with the Anaconda distribution.

Hardware used:
-RTL-SDR Dongle
-GTX 950 Graphics card
-DAB+/DVB-T LPDA Antenna
-Intel Core i7 6700 Quad Core 3.4GHz CPU
-16GB RAM

Passive radar works by looking for signals being reflected off objects such as aircraft. Strong signals from broadcast towers can easily be reflected off an aircraft towards a directional antenna, then correlated with the broadcast signal received from another antenna. Then with some clever processing the relative speed and distance of the object can be determined.

Real-time RTL-SDR Passive Radar w/ Clutter Suppression + Target Acquisition

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Building a DIY 137 MHz Band Pass Filter

Over on YouTube Adam 9A4QV has uploaded a video showing how to build a DIY bandpass filter for 137 MHz. This can help improve the reception of NOAA and Meteor M weather satellites, by blocking strong out of band signals. Adams design is a 132 MHz – 142 MHz Butterworth bandpass filter which gives about 35 dB attenuation outside of the pass band. He’s also posted a write up documenting the filter design on his website.

Lucas Teske recently went ahead and built the 137 MHz filter suggested by Adam. Lucas didn’t have the correct capacitor values so he ended up cascading several in series. His results showed that the filter did improve his reception significantly.

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