Category: SDRplay

December 23, 2015

SDRPlay RSP API Updated to Version 1.8.0

The SDRplay team have recently released a major update to their API and drivers. The new version is 1.8.0 and they write that it should remove the DC offset, reduce in band images from strong signals, and lower the noise floor. The SDRplay is a software defined receiver that costs $149 USD. They write:

We are pleased to announce release 1.8.0 of the API for the RSP. This is a major upgrade to the API with new features and an improved gain map which should result in improved performance over a key portion of the gain control range. Currently this API is available for Windows only, but versions for Linux and Mac OS and Android will follow shortly.

The API now incorporates automatic post tuner DC offset correction and I/Q compensation. This will almost completely eliminate the DC centre spike that was previously present in zero IF mode and also correct for amplitude and phase errors in the I/Q signal paths that can lead to in-band images when strong signals are present.

There is a new gain map for the RSP which should help improve the receiver noise floor for gain reduction settings in the range of 59-78 dB. To achieve this, the IF gain control range has been increased from 59 to 78 dB. In addition, the user can now turn the LNA on or off at any point within the IF gain control range. This means that the LNA can remain on for gain reduction settings of up to 78 dB, whereas previously the maximum gain reduction that could be attained whilst the LNA was on was only 59 dB. Being able to leave the LNA on will result in improvements in the receiver noise performance for gain reductions in the range of 59 to 78 dB. The upper 19 dB of the IF gain control range have now been disabled. In practice this part of the gain control range was useless as trying to operate within this region always lead to receiver overload even when signals were very weak.

To fully exploit the features of this new API release, we have also issued release 3.5 of the ExtIO plugin. This plugin will work with HDSDR, SDR sharp (releases 1361 or earlier) and Studio 1. Automatic I/Q compensation and DC offset correction will work with later versions of SDR sharp, but we will need to update the native plugin for users of these later versions to be access the new gain map.

Similarly, users of SDR Console will gain the benefit of automatic DC offset compensation and I/Q correction, but will not yet be able to access the new gain map. We hope that a version of SDR console that unlocks this feature will become available in the near future.

Until a new release of SDR-Console is available, you can copy the API into the SDR-Console installation directory…

from C:\Program Files\MiricsSDR\API\x64\mir_sdr_api.dll to C:\Program Files\SDR-RADIO-PRO.com\mir_sdr_api.dll

The API installer has also contains an extra certificate to be more user friendly for Windows XP, Vista and Windows 7 users.

The new API and ExtIO plugin can be downloaded from our website at:www.sdrplay.com/windows.html

As they write that in band images from strong signals are reduced in this version we decided to do a quick before and after test using our own RSP receiver. We tuned into some TETRA signals that had exhibited images in the past on our RSP (you can see them as the yellow signals in the before image). In the new driver the images are completely gone.

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December 23, 2015

SDRPlay RSP API Updated to Version 1.8.0

We are pleased to announce release 1.8.0 of the API for the RSP. This is a major upgrade to the API with new features and an improved gain map which should result in improved performance over a key portion of the gain control range. Currently this API is available for Windows only, but versions for Linux and Mac OS and Android will follow shortly.

The API now incorporates automatic post tuner DC offset correction and I/Q compensation. This will almost completely eliminate the DC centre spike that was previously present in zero IF mode and also correct for amplitude and phase errors in the I/Q signal paths that can lead to in-band images when strong signals are present.

There is a new gain map for the RSP which should help improve the receiver noise floor for gain reduction settings in the range of 59-78 dB. To achieve this, the IF gain control range has been increased from 59 to 78 dB. In addition, the user can now turn the LNA on or off at any point within the IF gain control range. This means that the LNA can remain on for gain reduction settings of up to 78 dB, whereas previously the maximum gain reduction that could be attained whilst the LNA was on was only 59 dB. Being able to leave the LNA on will result in improvements in the receiver noise performance for gain reductions in the range of 59 to 78 dB. The upper 19 dB of the IF gain control range have now been disabled. In practice this part of the gain control range was useless as trying to operate within this region always lead to receiver overload even when signals were very weak.

To fully exploit the features of this new API release, we have also issued release 3.5 of the ExtIO plugin. This plugin will work with HDSDR, SDR sharp (releases 1361 or earlier) and Studio 1. Automatic I/Q compensation and DC offset correction will work with later versions of SDR sharp, but we will need to update the native plugin for users of these later versions to be access the new gain map.

Similarly, users of SDR Console will gain the benefit of automatic DC offset compensation and I/Q correction, but will not yet be able to access the new gain map. We hope that a version of SDR console that unlocks this feature will become available in the near future.

Until a new release of SDR-Console is available, you can copy the API into the SDR-Console installation directory…

from C:\Program Files\MiricsSDR\API\x64\mir_sdr_api.dll to C:\Program Files\SDR-RADIO-PRO.com\mir_sdr_api.dll

The API installer has also contains an extra certificate to be more user friendly for Windows XP, Vista and Windows 7 users.

The new API and ExtIO plugin can be downloaded from our website at:www.sdrplay.com/windows.html

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November 9, 2015

Watching ATSC TV with an SDRplay SDR and GNU Radio

ATSC is the digital HD TV standard used within the United States and Canada. It is 6 MHz wide so the RTL-SDR with its maximum bandwidth of about 2.8 MHz cannot decode this signal. However, higher end SDR’s such as the SDRplay, Airspy and HackRF have larger bandwidths that can easy cover 6 MHz.

One SDRplay owner was able to figure out a way to decode ATSC by using a decoder written in GNU Radio. With the process the author used we note that other wide band SDR’s such as the Airspy and HackRF should also be capable of achieving the same results.

The process the author used was to first record a RAW IQ WAV file in HDSDR in Windows, making sure that any DC spike correction is applied. The WAV file is then opened in a premade GNU Radio flow graph in Linux and processed into an MPEG file. The process is not real time. The authors article shows a step by step tutorial on how its done.

In an update post to his results the author also notes that to successfully do a recording at the maximum SDRplay bandwidth of 8 MHz a RAM disk or perhaps SSD is required so that samples are not dropped.

An ATSC signal shown in HDSDR received with an SDRplay

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November 1, 2015

SDR-J Now Compatible with the Raspberry Pi 2

The popular software DAB (Digital Audio Broadcast) decoder SDR-J has recently been updated and can now run on the Raspberry Pi 2. In addition the author has also added experimental DRM decoding capabilities to his shortwave receiving software. The author writes about the Raspberry Pi 2:

The Raspberry PI 2 has a processor chip with 4 computing cores. By carefully spreading the computational load of the handling of DAB over these cores it is possible to run the DAB software on the Raspberry PI 2.

In my home situation the – headless – Raspberry PI 2 is located on the attic and remotely controlled through an SSH connection using the home WiFi on my laptop in my “lazy chair”. To accomodate listening remotely, the DAB software on the Raspberry PI 2 sends – if so configured – the generated PCI samples (rate 48000) also to an internet port (port 100240). On the laptop then runs a very simple piece of program reading the stream and sending it to the soundcard

DAB is a digital audio protocol that is used in some countries as a digital alternative to broadcast FM (music stations). SDR-J is a suite of programs that includes the ability to decode DAB, FM, and several shortwave modes such as AM, USB, LSB, PSK, RTTY, WeatherFax, SSTV, BPSK, QPSK, CW, NavTex (Amtor-B), MFSK, Domino, Olivia, Hell, Throb and now DRM. It can directly connect to RTL-SDR receivers as well as other hardware such as the Airspy and SDRplay.

Screenshot of SDR-J running on the Raspberry Pi 2.

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October 20, 2015

Another L-Band Antenna Build and comparing L-Band reception on the RTL-SDR, HackRF and SDRplay

Over on Reddit user killmore231 has made a post showing his comparison of L-Band reception with RTL-SDR, HackRF and SDRplay software defined radios. killmore231 built the L-band patch antenna which Adam 9A4QV showed how to build on his YouTube channel late last month.

When testing the antenna on his RTL-SDR he saw no reception of any L-band signals at all. The RTL-SDR requires an external LNA to properly receive signals at this frequency range, which he did not have. Next he tried it on his HackRF and saw that some signals were weakly visible. When he tried it on his SDRplay the L-band satellite signals were clearly visible, probably due to the SDRplay’s good sensitivity at this frequency range and the fact that it has a built in LNA. His results show that the SDRplay is a good SDR for receiving L-band satellites as it does not need an external LNA for decent reception. An external LNA may still be needed if a long run of coax cable is used however.

SDRplay reception of L-band satellite signals with no external LNA.

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October 13, 2015

Demonstrating the Dynamic Range on the SDRplay RSP

The SDRplay radio spectrum processor (RSP) is a $150 USD software defined radio that can be considered as a next stage level up from the RTL-SDR dongle. We also consider it a competitor to the $199 USD Airspy SDR.

Over on YouTube the SDRplay designers have posted a video that demonstrates the dynamic range that is possible with their SDR. Dynamic range is a measure that defines the range between the strongest and weakest signal that can be received. So for example, if you have two signals near to each other on the frequency spectrum, dynamic range defines how much stronger can one signal be compared to the other before the weaker signal disappears into the noise.

In the experiment they use two frequency generators to generate a simulated wanted signal at 98.4 MHz and an unwanted blocking interferer at 98.7 MHz. They show that by reducing the IF bandwidth in their configuration screen and thus tightening the internal filters that the dynamic range can be increased to about 70 dB.

Previously Leif sm5bsz performed some similar tests, comparing many SDRs against one another, but did not utilize the programmable IF filters in the SDR Play RSP perhaps undervaluing the best possible dynamic range by about 5-10 dB.

SDRplay RSP FM Dynamic Range Demo

Watch this video on YouTube

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September 8, 2015

HAMSPIRIT.DE’s Review on Airspy vs SDRPlay

Over on the hamspirit.de blog author January has just uploaded his latest review comparing the Airspy with the SDRPlay (article in German, so use Google Translate if necessary). These are two mid price range RX only software defined radio receivers that many people see as a first upgrade from an RTL-SDR dongle. Currently, the Airspy sells for $199 USD and the SDRPlay sells for $149 USD.

In his review January uses the SDR# to compare both devices on a wide range of signals include a beacon in the 10M band, broadcast FM stations, another beacon in the 2M band, TETRA signals and trunked radio in the 70cm band. He ran the SDRPlay at a bandwidth of 1.536 MHz and the Airspy at a bandwidth of 2.5 MHz, with decimation set to 2 in order to get comparable bandwidths.

From the results it appears that overall the two SDR’s are quite comparable to one another. But the SDRPlay has the advantage that it’s frequency range covers shortwave frequencies and his results show that the SDRPlay had better SNR in the FM broadcast band (although these results may be incorrect as it appears that his gain settings were not set properly, as the Airspy guide recommends that Airspy gains be adjusted to keep the noise floor near -80 dBFS). On the other hand the Airspy was much better when strong FM overload was present as shown in his TETRA results. In his conclusion he writes (translated from German to English):

If one value to a SDR, which covers with the short wave, it is running out on the SDRplay.

If one is interested in the field below the 70cm amateur radio bands, is in my view the Airspy front.

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August 14, 2015

New drivers for the SDRPlay released: No more frequency gap

The SDRPlay is a $149 USD software defined radio with a 12-bit ADC, 8 MHz of bandwidth and a 100 kHz to 2 GHz tuning range. It is a good upgrade to the RTL-SDR and can be considered as a competitor to the Airspy SDR.

One of the initial cons of the SDRPlay was that it had a tuning gap from 380 MHz to 420 MHz. The gap was due to hardware limitations and had nothing to do with censorship. However, now the SDRPlay team have released a new API which fixes these limitations and can fully close the gap.

Along with this update they have also released a new EXTIO driver file with the following improvements:

Implementation of a selectable 1st LO frequency for the block converter. This will apply to frequencies below 60MHz (up-converted) and between 250MHz and 420MHz (down-converted). This allows full coverage between 100kHz and 2GHz in AUTO mode or the re-position of interferes at the expense of coverage range

Added a down conversion routine to convert Low IF modes to Zero IF modes for compatibility in SDR interfaces. IF bandwidths below 1.536MHz supported choice of IF Frequency and sample rate are restricted.

Added Options to control the DC offset compensation mode used by the tuner. Available modes are Static, Periodic, One-Shot and Continuous

Improved robustness when dynamically changing between IF modes and sample rates

The new drivers can be downloaded from sdrplay.com/platforms.html.

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July 7, 2015

A Review of the SDRPlay Software Defined Radio

In the May 2015 issue of The Spectrum Monitor magazine, the SDRPlay was reviewed in an article by Thomas. Now the article has been released for free over on the swling.com blog. The SDRPlay is a $149 USD software defined radio with a tuning range of 100 kHz – 380 MHz and 430 MHz – 2 GHz, a 12-bit ADC, and up to 8 MHz of bandwidth. We consider it as a decent upgrade to those wishing for something better than the RTL-SDR and a good competitor to the Airspy SDR.

In the review Thomas unboxes the unit, installs the software and reviews the HF DX performance comparing it to the more expensive Elad-FDM S2. While the performance isn’t as good as the Elad, Thomas writes that for the price it performs very impressively. In his conclusion he writes:

[The] SDRplay RSP really impressed me from the beginning with its low noise floor, variable IF bandwidth options, and relative ease of installation. Since the RSP only requires one USB cable for both data and power, it’s also an ideal portable SDR.

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