Tagged: spectrum spy

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.

Spectrum Spy: New Spectrum Analyzer Software for the Airspy

Software defined radio's can easily be used a very wideband spectrum analyzers by quickly stepping through the spectrum at the largest stable bandwidth supported. The RTL-SDR has had this functionality for some time now through software such as rtl_power and RTL Scanner.

Now Youssef, co-creator of the Airspy and programmer of SDR# has released a similar program for the Airspy called Spectrum Spy. The software comes bundled with the latest SDR# download which can be obtained from airspy.com.

The Airspy is a $199 USD software defined radio with a similar tuning range to the RTL-SDR, but it is significantly better with its 12-bit ADC and up to 10 MHz of instantaneous bandwidth. We review the Airspy, SDRplay RSP and HackRF in this post. With its large instantaneous bandwidth and fast retuning speed the Airspy makes an excellent spectrum analyzer that refreshes very quickly.

Youssef stresses that the software is still in proof of concept stages, and various features are still to be added in the future. He writes:

A new utility app is available for download with the standard SDR# package. It allows the visualization of larger frequency spans by exploiting Airspy's fast frequency tuning capability. The scanning speed is comparable to real spectrum analyzers (may be faster even!) The project is still in a PoC state, but the basic functionality provided is fully operational.

It all started when some customer wanted an example code to implement their own SA using Airspy, so I did more than a code snippet. I hope you enjoy!

We tested the Spectrum Spy software on several bands, and recorded short videos shown below to show how fast it is. 

20 MHz Bandwidth Mobile Phone Band

50 MHz BCFM Band

100 MHz Bandwidth Mobile Phone Band

Includes the uplink and downlink portions. We used our mobile phone to make a call and you can see the uplink at 895 MHz.

1 GHz Full Spectrum

Tweeted Photos

Over on Twitter @uhf_satcom has also been testing out Spectrum Spy and has got some good shots of Ku and L-band satellite bands.

Here @supertrack_it has been using Spectrum Spy to help with the tuning of his 1420 MHz filter.