We are going to be exploring SDR to check out live aircraft tracking. SDR++ is up and running on both my Windows 10 laptop and Asus Chromebook. SDR++ appears to be working well. Even with the minimal antenna purchased with the RTL-SDR receiver, I’ve been able to listen to a number of frequencies.
Starting out with gear I already have and know is working, I tried the RTL-SDR dongle out on the 2m ham radio band during the local radio club net.
I dialed in the settings on SDR++ and got a clear audio signal of the local ham radio operators chatting on a repeater about twenty miles away.
I wanted to see what else I could do with SDR. I am near a small international airport, under major commercial flight paths and near a number of military bases, including a military airfield. I wanted to see if I could hear aircraft communications, but the antenna setup was not ideal and I didn’t have much luck.
I wanted to see if I could track aircraft constantly flying overhead. Aircraft have transponders and other technology using Automatic Dependent Surveillance-Broadcast(ADS-B) to transmit their location in real time. ADS-B operates on 1090MHz. There was a good deal of traffic on 1090MHz, but SDR++ does not have ADS-B capability.
Here is the same signal using a Low Noise Amplifier(LNA). More on this later, but a LNA makes a weak signal a bit stronger(amplifies) without degrading the signal to noise ratio(SNR). SNR is basically the strength of the signal you want compared to the background noise. Enough basic electronics for one blog post, but sooner or later, you’ll have to learn something.
The signal is stronger and the background noise is higher, but at first glance, it appears the LNA has a positive impact.
There are signals, but where are the planes? This is software-defined radio, so we need software to define the signal we want, which is ADS-B. SDR++ does not do this at this time.
What is needed is software with an ADS-B demodulator. I know I promised no more electronic jargon, but a demodulator separates a signal from a carrier wave. It’s basic radio.
I wanted to use Dump1090 and Virtual Radar Server with the RTL-SDR receiver, but both programs are old, I could not get any device drivers that would work with my Windows 10 laptop. I gave up on that and downloaded and installed SDRangel. It has a good ADS-B demodulator and before long I was tracking civilian and military aircraft up to 75 miles away with a small antenna.
Tracking aircraft is a cool feature of SDR. There will be more SDRangel, ADS-B, LNAs and the antenna shop is about to open, so check back soon.