When people consider upgrading from the RTL-SDR, there are three mid priced software defined radios that come to most peoples minds: The Airspy, the SDRplay RSP and the HackRF. These three are all in the price range of $150 to $300 USD. In this post we will review the three units and compare them against each other on various tests.
Note that this is a very long review. If you don’t want to read all of this very long post then just scroll down to the conclusions at the end.
What makes a good SDR?
In this review we will only consider RX performance. So first we will define some terminology, features and specifications that are required for a good RX SDR.
SNR – When receiving a signal the main metric we want to measure is the “Signal to Noise” (SNR) ratio. This is the peak signal strength minus the noise floor strength.
Bandwidth – A larger bandwidth means more signals on the screen at once, and more software decimation (better SNR). The downside is that greater CPU power is needed for higher bandwidths.
Alias Free Bandwidth – The bandwidth on SDR displays tends to roll off at the edges, and also display aliased or images of other signals. The alias free bandwidth is the actual usable bandwidth and is usually smaller than the advertised bandwidth.
Sensitivity – More sensitive radios will be able to hear weaker stations easier, and produce high SNR values.
ADC – Analogue to digital converter. The main component in an SDR. It samples an analogue signal and turns it into digital bits. The higher the bit size of the ADC the more accurate it can be when sampling.
Overloading – Overloading occurs when a signal is too strong and saturates the ADC, leaving no space for weak signals to be measured. When overloading occurs you’ll see effects like severely reduced sensitivity and signal images……
Airspy vs RTL SDR receiving VLF
From the hills of Tennessee, Kirk Pickering, K4RO, operates a SO2R, single operator 2 radio, contest station and makes over ten-thousand contacts a year. Using Beverage antennas, Kirk is abl... Read more
“We demonstrate the two major new features of the latest version of Yaesu’s “991” series, the FT-991A. Watch the colour screen close up and see the waterfall display... Read more
Amateur Radio station WX4NHC at the National Hurricane Center in Miami will conduct its annual station test on May 30, 1400 until 2200 UTC. The purpose of this event is to test Amateu... Read more
Phyllis Randle from MFJ is interviewed by Tim Duffy, K3LR at DX Engineering in Tallmadge, Ohio Phyllis Randle from MFJ is interviewed by Tim Duffy, K3LR at DX Engineering in Tallmadge... Read more
At press time, more than 70 qualifying islands had been registered for “activation” this Saturday for the 2015 US Islands One-Day Getaway event. Individuals and teams will take to the... Read more
“January 11, 1965, a breathless Novice wraps his fist around the key and bangs our his first call on 40 cw, the ink still wet where he signed the license that was waiting in the... Read more
PRESS RELEASE The SEISA/Foundation for Global Children is pleased to announce our next activity as “Eritrea Project 2015”. As part of this project, we will conduct an amateur radio DXpedition from Asmara Eritrea, from March 6th to 1... Read more