Category: SDRplay

SDRplay Spectrum Analyzer Alpha Version Released

Steve Andrew has just released an alpha version of a Windows Spectrum Analyzer app for SDRplay SDRs that he's been working on. The app is currently still in alpha, meaning that all the features are not yet implemented. In particular, scans larger than the SDRplay's maximum bandwidth of 10 MHz are not ready yet. In the future the app will be able to scan swath's of bandwidth up to 2 GHz wide, similar to what SpectrumSpy for the Airspy and rtl_power for the RTL-SDR does.

We are pleased to announce the availability of the first cut of Spectrum Analyser software developed by Steve Andrew specifically for the RSP line of products. Please note that this is first alpha software and so it is still very much in development and some features are still to be added. Currently supported are:


This first alpha release gives a good idea as to the look and feel for the software. The main functional limitation is that sweeps of greater than 10 MHz are not currently supported. Steve is currently re-working the algorithms for providing wider sweeps than 10 MHz to improve sweep time and remove the issue of the DC spike in ZIF mode, so please bear with him.

We recommend using the software with AGC turned off and use manual control of the gain for better display stability.

Please use this forum thread to post any issues. Read the issues already raised and only post if the issue you have found hasn’t been raised. This will help Steve in his development.

Further development information can be found on the forum.

Click here to download the 0.9a Alpha release.

SDRplay Spectrum Analyzer Alpha
SDRplay Spectrum Analyzer Alpha

QuestaSDR Android App now with Remote Network Streaming: RTL-SDR, Airspy, SDRplay Supported

Back in April we posted about QuestaSDR, which had just released the Android version of its SDR software. Recently QuestaSDR programmer 'hOne' wrote in and noted that a new update has enabled remote streaming in QuestaSDR.

To get set up, just run the Windows version of QuestaSDR on a PC, and open the "SDR Server" app. Once the server is running, you can connect to it via the Android version of QuestaSDR over a network connection. The server supports the RTL-SDR, Airspy and any ExtIO compatible device such as SDRplay units. As far as we're aware, this is the only Android app that currently supports streaming from non rtl_tcp compatible units such as the Airspy and SDRplay.

hOne has been able to run an Airspy at the maximum bandwidth of 10 MSPS through his network connection. He also notes that you can now zoom into the IF spectrum in detail by using the new "IF Spectrum" plugin.

hOne also notes that the streaming feature is currently in beta, and any bugs/suggestions or feedback are welcome.

QuestaSDR Streaming over a network connection with an Airspy
QuestaSDR Streaming over a network connection with an Airspy

AirSpy windows server, android client LAN Remote
AirSpy windows server, android client LAN Remote

SDRplay Release a Dual Tuner SDR called RSPduo

The RSPduo
The RSPduo

SDRplay have released a new product at this years Hamvention called the "RSPduo". The product uses the same technology as their previous RSP models, but this time includes a phase-coherent dual tuner architecture which allows you to tune to two completely separate 2 MHz bands of spectrum simultaneously. The RSPduo retails for US $279.95 + shipping. Their press release reads:

Today at the Dayton Hamvention, SDRplay is announcing the launch of a new Software Defined Radio product – the RSPduo.

The RSPduo is a radical new addition to the RSP line of SDR receivers from SDRplay. Architecturally, it is different from any previous RSP in that it features dual independent tuners, both piped through a single high-speed USB 2.0 interface.

The SDRplay RSPduo is a dual-tuner wideband full featured 14-bit SDR which covers the entire RF spectrum from 1kHz to 2GHz giving 10MHz of spectrum visibility. Initially using Windows based ‘SDRuno’ supplied by SDRplay, you can simultaneously monitor two completely separate 2MHz bands of spectrum anywhere between 1kHz and 2GHz.

Superficially the RSPduo looks identical to the highly popular RSP2pro and will be able to operate in a very similar way. However, it also allows a completely new and exciting set of usage scenarios such as:

1. Simultaneous monitoring of two widely spaced bands – e.g. 40m (HF) and 2m (VHF)
2. Mixing and matching applications simultaneously – e.g. ADS-B and ATC scanning
3. Phase and time coherent demodulation of two receivers

Scenario 3 is very difficult to achieve with two separate USB devices because of the uncertainty of USB latency. The RSPduo overcomes this limitation because all traffic goes through a single USB interface, thus enabling the possibility of the development of various types of diversity demodulation such as: spatial, frequency and polarisation which can bring huge benefits in terms of improved performance.

As well as adding a second independently controlled tuner, which in itself, offers a whole new set of exciting usage possibilities, the SDRduo features 14bit ADCs and a completely re-designed RF front end. These changes provide better RF selectivity and even more dynamic range, offering outstanding performance under extremely challenging reception conditions. The combination of performance and features makes the RSPduo our highest spec RSP yet and sets a new benchmark in the sub $300 SDR market.

Lots of great new videos are appearing on YouTube showing the Dual Tuner RSPduo in use. Just search for RSPduo in the YouTube Search bar.

So far several reviews have been released: review:

Sevenfortyone video:

Tech Minds video 1:

Tech Minds video 2 showing ATC and ADSB together:

OG! Review:

While it appears that it will be a useful tool for multi-band monitoring, what we're looking forward to most are the phase coherent applications. Thanks to its phase coherence and predictable USB timing implementation, the unit should be very useful for passive radar and spatial filtering techniques, and we're hoping that SDRplay will be working on software for at least the latter. Multi-channel phase coherent applications are probably going to be one of the the next big developments in the SDR space so it's good to see low cost hardware with this potential coming out now.

We'll be reviewing the unit ourselves within the next month, so keep an eye out for that post!

RSPduo - introduction and software demonstration
RSPduo - introduction and software demonstration

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: (formerly listed as mansnothot01)

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:

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.

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

Airspy HF+ R3 Modification test
Airspy HF+ R3 Modification test

Demonstrating the MFJ-1708SDR Automatic Relay Switch with an SDRplay and Icom IC7300

A few weeks ago we posted about the MFJ1708SDR automatic relay switch and how it can be used to combine an RX only SDR with a transmit capable radio. An automatic antenna relay switch is used to automatically ground the SDR's antenna input whenever the TX capable radio transmits in order to protect the SDR's front end from blowing up due to high TX power.

In this YouTube video Pete Sobye shows us the MFJ1708SDR working together with an Icom IC7300 HF radio and an SDRplay which is being used as a panadapter. For software Pete uses HDSDR and Omnirig which allows the PC to control the IC7300.

Icom IC7300 panadapter MFJ-1708SDR, SDRPlay, HDSDR and OmniRig
Icom IC7300 panadapter MFJ-1708SDR, SDRPlay, HDSDR and OmniRig

Optimizing the RSP1A at LF/MW/HF by Understanding Intermodulation

SDRplay have recently published an informative white paper that explains what intermodulation and higher order mixing effects are, and how they can affect reception on an SDR such as the SDRplay. This paper could be a useful introduction to understanding how to optimize reception of weak signals when they are in the presence of strong signals. While written for the SDRplay, the same knowledge and tips could be applied to any similar SDR.

Later in the paper they also show how to eliminate intermodulation effects by enabling the MW/AM notch filters on the SDRplay RSP1A unit, and by carefully choosing the LO frequency.

The RSP1A covers the spectrum from 1kHz to 2GHz, and phantom signals can be a menace for all wideband SDR receivers. More and more is being published about the most obvious culprit which is inter-modulation caused by very strong interferers such as MW/FM broadcast transmitters – indeed, all the current SDRplay RSPs have built in filters to help reduce the problems caused by that.

But the reality is, particularly at HF and below, that a phantom signal may occur for other reasons such as higher order mixing effects. Sometimes, it can be difficult to know what is the cause of the phantom signal. If you can understand the cause, there are additional steps you can take to overcome it.

We’ve just published this white paper to explain the difference between intermodulation and higher-order mixing effects, and what practical steps you can take to reduce the latter in particular. Our example uses an RSP1A operating at frequencies below 60MHz.

First pager of the SDRplay whitepaper on intermodulation effects.
First pager of the SDRplay whitepaper on intermodulation effects.

A Guide to Using SDR-Console V3 for Accessing and Creating Remote Servers

Jon Hudson, head of marketing at SDRplay has recently released a helpful tutorial that shows how to access remote servers in SDR-Console V3, and also how to set up your own server too. As you may already know, SDR-Console V3 provides a remote server platform which allows you to access all sorts of SDR hardware remotely over a network connection or over the internet. Some SDR hardware owners even opt to share their radio hardware publicly over the internet for anyone to access. The video description reads:

This video is a screen-by-screen guide to both accessing, and setting up your own, remote SDR radio using the new (Feb 2018) SDR Console V3 software from SDR-Radio. Although the guide uses an RSP2 from SDRplay, this will work with all the popular SDRs

Please note - you need to have a good internet connection since (unlike in V2), the entire I/Q data is being sent over the internet. This also limits how much visual bandwidth you are can see at any one time.

Links referenced in this video:
More videos on

Be careful not to plug multiple SDRs into a single USB2 socket - for multiple SDRs, you may need a powered hub ( like this: )

Once you are up and running - please go to and view your listing - if there is a yellow triangle, then you are not accessible outside your own firewall - attention is needed! Just because you can access it on your own LAN doesn't mean it's accessible via the internet!!!

The RSP family of SDRs from SDRplay cover 1kHz to 2 GHz with no gaps and give up to 10MHz spectrum visibility.

Jon's video first shows how to use SDR-Console V3 to access those publicly shared SDR radios over the internet. The second part of the video demonstrates how to set up your own server that you can use remotely for personal use, or to share over the internet.

The SDR-Console V3 server accepts various kinds of SDR hardware including RTL-SDR, Airspy, SDRplay, HackRF, Elad, LimeSDR and many more SDR units so this is a good way to explore various types of hardware, or simply to explore signals from different areas around the world.

SDR-Console remote access for SDR Radios
SDR-Console remote access for SDR Radios