It’s that time of year again when Martin Lynch and Sons throw open their doors.  Their store at Staines (near Heathrow Airpost) is a great location for easy road access for many in the south of the UK.  Andy from SDRplay will be there demonstrating the latest software updates and answering questions.

It’s a great opportunity to talk to Andy anbout the latest SDRconnect developments such as rig control and the powerful control options for the nRSP-ST networked receiver which is ideal for small groups of people to share.

More details of the Martin Lynch and Sons open day here

Above: From the archives: GNU radio champion Derek with Andy from SDRplay at the RSGB Convention back in 2017!

Unfortunately due to illness and supporting Pacificon in the USA, SDRplay is unable to be at the RSGB Convention here in the UK this weekend of October 11th and 12th.  But not to worry, Martin Lynch and sons will be there to answer questions and if you mention this blog, they have some special offer pricing available.

Even if you can’t be at the show but have friends there, get them to buy on your behalf!  The budget-friendly RSP1B is the perfect Christmas gift for encouraging retired hams back into the hobby and at the other end of the spectrum, the youngsters are discovering the magic and freedom offered by radio communications. Don’t let them get put off by the limitations of a cheap dongle or Chinese ripoff!

If you have a club who needs reliable access to a decent receiver, club together to get an nRSP-ST, now with new administrator software to make it easy to safely share a unit located in a noise free location with a good antenna and an internet connection.

For those of you at the convention,  go to the Norfolk nRSP link on this page to try out Chris Danby’s superb setup. Click on the URL under Norfolk UK on this nRSP-ST demo page: https://www.sdrplay.com/try-accessing-an-nrsp-st-networked-receiver-today-2/

It will work on your iPhone or Android device.  I think Chris Danby (RSGB publicty/events man) would enjoy you going up to him to tell him what you think of his setup!!!

Enjoy the event in Milton Keynes, UK. Details here:  https://rsgb.org/main/rsgb-convention-2025/

SDRconnect v1.0.5 build 583e89db6 was released October 4th.

To operate this release with nRSP-ST, the firmware must be updated to at least 1.0.11

Changed
• Linux installers will only check for Ubuntu compatible packages
• To skip dependency checks on unsupported Linux distributions, use (replace example.run with downloaded .run installer filename) …
o NOTSUPPORTED=true ./example.run
• Linux minimum HamLib supported version set to 4.5 (recommend 4.5.5 to 4.6.5)

Corrected Defects
• Pressing TAB repeatedly or holding it down could cause SDRconnect to unexpectedly exit
• mp3 library was missing from the Windows installer
• MacOS server would abort due to a bind failure
• Cleaned up server list of streamable sources
• HamLib bridge missing from the Linux/ARM64 installer
• Rig Control – OmniRig interface updated to support either pmFreq or pmFreqA as defined in the rig ini file

SDRconnect v1.0.5 build e077f2ebe was released 26th September 2025

To operate this release with nRSP-ST, the firmware must be updated to at least 1.0.11 – this also has a fix for Safari 26 users

Added
• Diversity support over the network via server (requires RSPduo)
• MP3 Audio recording support
• Rig control support
o Omni-Rig (windows only)
o HamLib
• Waterfall gradient preview
• Show ticks on the RF gain slider
• Slider to change noise reduction strength
• Option to enable NFM deemphasis
• Option to display spectrum frequency markers in relevant unit
• Option to enable hold with decay on main spectrum
Changed
• Improved CW mode filter performance
• Application and server memory usage improvement
• Display application version in title bar

Corrected Defects
• Touch controls in the waterfall were active whether they displayed or not
• RDS decoder filtered out characters in the extended ASCII set
• RDS decoder did not work at all sample rates
• Copy/paste frequency between tabs required a frequency in the destination tab to be selected
• Switching frequency tabs whilst the edit field padlock was open caused a crash
• Bandwidth resize could be performed for DSB and LSB when mouse was in the frequency bar
• Inconsistent style on remote devices dialog
• IQ playback file selection was disabled when streaming was stopped

NRSPAdministrator (for nRSP-ST)

Added
• Logging of connection activity
• Ability to take control from client (admin user only)
• Ability to assign control to a user
• List of active/connected users

Corrected Defects
• Editing users required a password entry whether it changed or not
• Date/Time of recording shown was always UTC regardless of regional setting

Earlier this month, the SDRplay team enjoyed meeting folks at the UK National Hamfest. Events like that remind us how important it is to meet face to face with our loyal customers as well to get feedback and to listen to suggestions for future improvements.  Coming up are the following events:

Andy from SDRplay will be running SDRplay demos and answering questions at the Dover (UK) Amateur Radio Club Rally on Saturday 20th September at St Radigunds Community Centre, Poulton close, Dover CT17 0HL in the UK – more info on https://darc.online/rally

Then in October, SDRplay will be joining Ham Radio Outlet at Pacificon, Friday, October 10 – Sunday, October 12, 2025 at San Ramon Marriott, 2600 Bishop Drive, San Ramon, CA  94583, USA. A great opportunity to see the latest dmeos and ask questions. 

SDRplay will be at the UK National Hamfest September 5th-6th 2025:

September 5th update – a welcome video clip: https://www.youtube.com/shorts/PEr802PdZIU

We are getting ready for the show and looking forward to meeting customers old and new.  It’s a great opportunity to meet some of the SDRplay team and ask your questions.

Try accessing an nRSP-ST today!

What’s different about the nRSP-ST compared with a regular SDRplay RSP?

The nRSP-ST lets you:
• Access your personal RSP from any point in your house or when away from home
• Share your RSP with friends or colleagues by allocating usernames and passwords with timeout options

The nRSP-ST is like a traditional SDR receiver but with a fundamental new advantage which is the ability to place the unit wherever it works best and access it from wherever is most convenient. The nRSP-ST is a self contained remote receiver box which doesn’t require a local computer. It is specially designed for continuous unattended operation.  It just needs an antenna and an internet connection.  The SDRconnect client software provides a robust and flexible interface to whatever decoding apps are chosen. The addition of a web browser (and eventually an Android/iOS app) provides convenience for people who are on the move without access to a laptop. More about the nRSP-ST here

About this demonstration:

You can play with a real nRSP-ST over the internet

You can try out SDRconnect software before buying any of the SDRplay products. See how it runs on Windows, MacOS, Linux or Raspberry Pi.

You can have access to the following nRSPs:

Northern Germany:
-Hostname (for SDR connect client):  intranet.baltic-lab.com
-Port number (for SDRconnect client): 50000
-Web Server url (not “secure” but trusted): http://sdr.baltic-lab.com:9001
-Username (case senstive):  BalticLab
-Password (case sensitive):  BalticLab
-Timeout (control passes to next in line): 30 minutes
-Antenna (important to check): B: Mini-Whip (10 kHz – 30 Mhz)

UK, Bedfordshire  :
-Hostname (for SDR connect client): nrsp.ddns.net
-Port number (for SDRconnect client): 50002
-Web Server url (not “secure” but trusted): http://nrsp.ddns.net:9001/
-Username (case senstive): Test
-Password (case sensitive): Test
-Timeout (control passes to next in line): 15 minutes
-Antenna (important to check): A: G5RV wire dipole MF through VHF

UK, Norfolk:
-Hostname (for SDR connect client): g0dwv-remote.ddns.net
-Port number (for SDRconnect client): 50000
-Web Server url (not “secure” but trusted): http://g0dwv-remote.ddns.net:9001/
-Username (case senstive): Test
-Password (case sensitive): Test
-Timeout (control passes to next in line): 15 minutes
-Antenna (important to check): C – subject to change: End-fed 40-10 wire

USA, Colorado:
-Hostname (for SDR connect client):  amigasteve.dyndns.org
-Port number (for SDRconnect client): 50000
-Web Server url (not “secure” but trusted):  http://amigasteve.dyndns.org:9001/
-Username (case senstive): Demo
-Password (case sensitive): test
-Timeout (control passes to next in line): 15 minutes
-Antenna (important to check): TBD: Endfed 40-10  + another coming soon

The Northern German nRSP-ST is maintained by Baltic-Lab – checkout their excellent YouTube Channel: https://www.youtube.com/@BalticLab   There is also a webpage dedicated to the nRSP-ST demo: https://baltic-lab.com/websdr/

These nRSPs are available on a first come first served basis.  The UK nRSP-ST has a G5RV wire dipole on Antenna A which has best performance over the HF frequencies but also good signals from MF (AM band) to VHF (FM and aircraft bands).  Please be patient if you find you have to wait for access. At times it may be oversubscribed. We have set timeout limits. Please note that only the first user gets to select the frequency range.

You can access the actual nRSP-ST server directly from your web browser by simply clicking on the Web Server url link listed above.  Read the notes lower down about entering the username and password.

You can also try accessing the demo nRSP-ST from a copy of the SDRconnect client software – download it (for Windows, MacOS or Linux) from here

You can then add one of the remote nRSPs by clicking on the 3 dots and choosing “Remote server”. Fill in the details as shown below:

The easy access from the built-in web server (e.g. for an Android or iOS device) can be found by going to the “Web Server url” shown above,  on your web browser – the web interface takes up to 30 seconds to set-up the graphical user interface so be patient.  Also some older tablets and phones may not work.

For both forms of access, you will need to enter username and password (they are case sensitive)  – you can see your place in the queue by clicking on the network symbol. For small devices, once you have your settings chosen, minimise the control panel to give room for the spectrum display. Also click on the hand symbol to enable the special fingers controls for zoom and tune.

Here are some things to check when using the web version:

(Please note this appears in your browser to be a “non secure” website because these units create web servers which are usually shared with friends and colleagues so self-signing certification is not an issue)

  -First press the green “Play” arrow (top left) and enter the (case sensitive) username and password

  -Choose the appropriate “mode” in the control panel- eg LSB or USB for HF ham bands (you can change away from the default filter bandwidth as well). It will start in wideband FM! Check it is set to the correct antenna  or you will hear nothing!

  -If you have control, you can choose your band or specific centre frequency from the band buttons or keypad. If someone else still has control, then you will have to use the band or frequency range already selected. Your tuning range will be limited.

–You can see your place in the queue by pressing the network symbol.

  -For small handheld devices, hold in “landscape” and slide the header row if needed with a finger. Select the hand symbol to enable finger controls for zoom and tune. 

  -For easy tuning of SSB signals, expand the spectrum display scale to a smaller section of the band and then toggle off the control panel (top right button). Then swap back to holding the  device in “portrait” mode for fine tuning.

  -If you’re using an iPhone be sure not to have “silent mode” switched on!  (at the side) – otherwise you get no audio!

  -If you’re using an iPad, check silent mode is off.  Go to Settings, Sounds and turn off silent mode – otherwise on some iOS versions, you will get no audio!

If using the SDRconnect software for the first time , then we recommend viewing the video guides on https://www.sdrplay.com/sdrconnectvideoguides/ and the SDRplay Youtube channel

For newcomers to SDRplay, you can get some idea of the experience you would have if you had your own RSP plugged into your computer locally. The cheapest RSP is the RSP1B which has just one antenna port: https://www.sdrplay.com/purchase/

This video guide demonstrates using a small handhelp device like an Android phone or iPhone: https://youtu.be/424jdYWFoP0

How many simultaneous users can one nRSP-ST support?
The maximum number of simultaneous users that the device can support depends upon the connection mode, signal bandwidth and signal type (demodulation mode). For this demo we have not allowed full IQ as an option – due to internet bandwidth limitations. 
The limitation in the number of users is determined by the CPU and GPU load on the host inside the nRSP-ST. A lot of work has been done to balance the signal processing that is performed on the CPU vs the GPU to maximise the use of the available processing power. By this approach, we have been able to increase the supportable number of users by perhaps 50% when compared to software that exclusively uses the CPU. The most severe load is when using ‘compact mode’ for SWFM. In this case if there are more than 3 connections, then there may be some audio break up as all of the processing is being performed on the host itself. For lower bandwidth signals such as AM or SSB, the limit is a lot greater. In this case, the device can support up to 8 users. In
Full IQ mode, the limitation is really network bandwidth. The most useful mode in many ways is IQ Lite. For AM and SSB signals, it only uses about 2-3x the network bandwidth
of compact mode, but reduces the processing load on the nRSP-ST host considerably. It has all of the advantages of full IQ with the exception that it will not allow IQ recording on the client side.
At this stage, we have not attempted to artificially limit the number of connections that can be made. However, in a future release of the firmware, we will most likely add the ability for the owner/administrator to limit the number of simultaneous users, but we want to do that in an intelligent way that doesn’t place unnecessary restrictions, so we want to take account of the modes in which the connections are made.

The nRSP-ST is perfect for sharing resources e.g. for schools or radio clubs – click here to find out more