Tagged: spectrum analyzer

SATSAGEN: Software to use a PlutoSDR as a Tracking Spectrum Analyzer

Thank you to Frank, HB9FXQ for submitting news about a new Windows program called SATSAGEN which allows you to use a PlutoSDR as a wideband spectrum analyzer. SATSAGEN was created by Alberto IU1KVL and is entirely free to use. This makes it possible to get wideband scans of RF components like filters and attenuators. Together with a directional coupler it could also be used to measure the SWR of antennas as HB9FXQ demonstrates in his Twitter post.

The PlutoSDR is a low cost RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range. It is typically priced anywhere between US$99 - US$149 depending on sales.

In the video below Alberto demonstrates SATSAGEN performing some wideband scans, and he shows the various features of the software. He writes that the system has a scan range from 70 MHz to 6 GHz and can show results in dBm. The spectrum analyzer works with the TX part of the PlutoSDR to provide a tracking generator with resolution of up to 1024 points. The software can also use the PlutoSDR as a frequency generator with 1 kHz of resolution.

There is also a support group available at groups.io/g/satsagen.

SATSAGEN Screenshot
SATSAGEN Screenshot

SATSAGEN BASICS

SDRplay Spectrum Analyzer Software Updated to V1.0a

Steve Andrew, the author of the SDRplay Spectrum Analyzer software has recently released an update which enables several new features. This software allows you to use SDRplay SDRs to scan a wide swath of bandwidth by rapidly scanning in 10 MHz (or less) chunks over the SDRplay's frequency range. The SDRplay team write:

We are pleased to announce the availability of V1.0a of the Spectrum Analyser software developed by Steve Andrew specifically for the RSP line of products. This is a very-much upgraded version of the original alpha release and includes many new features as well as removing the limitations imposed on the previous version. New features include multiple traces, a versatile marker system with maths, peak find and display functions, Zero or non-Zero IF options and an upgraded tracking generator system. Currently support are: 

RSP1
RSP2/RSP2pro
RSP1A
RSPduo (single tuner mode)

SDRplay Spectrum Analyzer
SDRplay Spectrum Analyzer

RTL-SDR Retrogram: ASCII Art Spectrum Analyzer

Over on GitHub, Rakesh Peter (r4d10n) has uploaded a new terminal/ssh based console application called "retrogram~rtlsdr". This program uses an RTL-SDR and terminal window to display a spectrum analyzer drawn in ASCII art. Because it is terminal based, it is even possible to view the spectrum of a remote device over an SSH connection. The program is based on software designed for Ettus USRP SDRs, and has been adapted for RTL-SDR.

For other SDRs r4d10n has also worked on a "retrogram~soapysdr" version which should work with any SoapySDR compatible SDR, and "retrogram~plutosdr" for PlutoSDR SDRs.

Spektrum SV Mod: RTL-SDR Spectrum Analyzer Software Now with Improved UI

Spektrum is a popular spectrum analyzer program that is used with RTL-SDR dongles. It is based on the command line rtl_power software and is compatible with both Windows and Linux. Thanks to it's easy to use GUI it is an excellent piece of software for scanning and determining where active signals exist, or for measuring filters and antenna SWR with a noise source.

Recently SV8ARJ (George) and SV1SGK (Nick) have been working on extending the original open source Spektrum code. Their improvements focus around the UI and making it more functional and easier to use. Currently the updated branch is in alpha, and they are hoping that any testers could help report bugs, issues and wishes to them. The code is available on their GitHub and the latest Windows test build can be downloaded from their DropBox.

The changelog reads:

  • 2 Cursors for Frequency axis.
  • 2 Cursors for Amplitude axis.
  • Absolute and differential measurements with cursors.
  • Zoom functionality of the cursors's defined area (gain + frequency).
  • Mouse Wheel Gain adjustment on graph (Top area for upper, low area for lower).
  • Mouse Wheel Frequency adjustment on graph (left area for lower frequency, right for upper).
  • Mouse Wheel in the centrer of the graph performs symetric zoom in/out.
  • View/settings store/recall (elementary "back" operation, nice for quick zoomed in graph inspection).
  • Right click positions primary cursors.
  • Right Double Click positions primary cursors and moves secondary out of the way.
  • Left Double Click zooms area defined by cursors (Amplitude + frequency).
  • Left Mouse Click and Drag on a cursor moves the cursor.
  • Middle (mouse wheel) Double Click resets full scale for Amplitude and Frequency.
  • Middle (mouse wheel) Click and Drag, moves the graph recalculating limits accordingly.
  • Reset buttons to Min/Max range next to Start and Stop frequency text boxes.
  • Cursor on/off checkbox now operate on all 4 cursors.
  • ZOOM and BACK buttons.
  • Filled-in graph option (line or area).
  • Display of frequency, Amplitude and differences for all cursors.
  • Modified: Button layout.
  • Fixed: Save/Reload settings on exit/start. IMPORTANT : delete the "data" folder from the installation location if you have it.
  • Filling in graph option (line or area).
Spektrum UI Updates
Spektrum UI Updates

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:

RSP1
RSP2/RSP2pro
RSP1A

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

Poor Mans Spectrum Analyzer with an RTL-SDR and Noise Source

Over on YouTube channel Bootstrap Workbench has been running a series on using an RTL-SDR and noise source to create a poor man’s spectrum analyzer. So far he has three videos available. The first shows how to install and setup Spektrum, his preferred Windows based wideband scanner for the RTL-SDR.

The second video shows how the RTL-SDR, noise source and Spektrum can be used to tune a cavity duplexer. A cavity duplexer is an adjustable set of filters that allows you to use a single antenna for TX and RX at different frequencies. It can be tuned by adjusting screws on the unit body.

In the third video he shows how to examine the response of a dual ferrite isolator/circulator which is a device that can be used to ensure RF only travels in one direction. This could be use for example to prevent damage to a TX power amplifier from reflected signals due to high VSWR or other nearby powerful signals.

Poor Man's Spectrum Analyzer – Installing Spektrum and Testing an RTL-SDR com 88-108 Bandstop Filter
Poor Man's Spectrum Analyzer – Tuning Cavity Duplexers
Poor Man's Spectrum Analyzer – Examining a Dual Ferrite Isolator/Circulator

If you’re interested in this we also have our own tutorial available about setting something like this up, but using alternative software.

LimeSDR CrowdFunding Closing in Four Days: 80% Funded

The LimeSDR is a new transmit capable software defined radio with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and 61.44 MHz bandwidth which is currently seeking crowdfunding. At the time of this post there is about four days left to reach the $500k goal, and it is only 80% funded. To try and reach their funding goal they have released another batch of discounted units which cost only $249 USD. After the crowd funding campaign the price will rise to $289/$299 USD. If the LimeSDR is not funded in time, they write that the project will unfortunately be put on hold and it’s future may be uncertain. We believe that this product is shaping up to be a very good TX/RX capable SDR, like the HackRF and bladeRF, but much better overall and for the same or even lower price.

Recently they also released some new updates that show off some LimeSDR features. In a post previously featured on our blog beta tester Alexandru showed how he was able to get the LimeSDR to transmit DVB-S2 HDTV. In later updates they showed how the LimeSDR can be used to:

The LimeSDR Board
The LimeSDR Board

Using the Airspy as a low cost Spectrum Analyzer with Spectrum Spy

Over on his blog VK4ZXI has been testing the Airspy with the Spectrum Spy software. The Airspy is a $199USD software defined radio that can be considered as a high end upgrade to the RTL-SDR as it has 10 MHz of bandwidth and a 12-bit ADC. The Spectrum Spy software allows the Airspy to be used as wideband spectrum analyzer. In a previous post we reviewed the Spectrum Spy software with the Airspy and found it to have an extremely fast refresh rate. Recent updates since the review have made it even faster.

In his first post VK4ZXI compares the Airspy + Spectrum Spy with the RTL-SDR running RTLSDR-Scanner and Rtl_power, two spectrum analyzer programs written for the RTL-SDR. In his tests he finds that the RTL-SDR and Airspy can obtain similar scans, but the Airspy can scan and refresh the spectrum at much faster speeds than the RTL-SDR, thanks to its 10MHz bandwidth.

Airspy + Spectrum Spy receiving the entire digital TV band over 100 MHz.
Airspy + Spectrum Spy receiving the entire digital TV band over 100 MHz.

In his second post VK4ZXI uses the Airspy + Spectrum Spy together with a cheap BG7TBL noise source to measure the response of a cavity RF filter. This is the same BG7TBL noise source that we used in our “Measuring Filter Characteristics and Antenna SWR with an RTL-SDR and Noise Source” tutorial. The results from the cavity filter measurement show that the Airspy can potentially perform on a level close to an expensive spectrum analyzer.

Measuring the response of a UHF cavity filter with Airspy + Spectrum Spy.
Measuring the response of a UHF cavity filter with Airspy + Spectrum Spy.