G4NSJ – SDRplay RSP2pro software defined radio


I don’t know a great deal about the workings of software defined radios but I’ve learned this…

SDR stands for Software-Defined Radio, which is a radio communication system where the processing of radio signals is done using software rather than hardware. Instead of using traditional analog circuits and components, an SDR system uses digital signal processing (DSP) techniques to manipulate the radio signals.

In an SDR system, the radio signals are first converted from an analog waveform to a digital signal using an analog-to-digital converter (ADC). The digital signal is then processed using a variety of signal processing techniques, such as filtering, demodulation, and decoding, which are all performed using software running on a computer or specialized hardware.

One of the key advantages of an SDR system is its flexibility and versatility. Because the processing of the radio signals is done using software, it is relatively easy to reconfigure the system to work with different types of signals or frequencies. This means that SDR systems can be used for a wide variety of applications, including amateur radio, military communications, and scientific research.

Another advantage of SDR systems is their ability to process multiple radio signals simultaneously. Because the processing is done using digital signal processing techniques, an SDR system can process multiple signals on different frequencies simultaneously, allowing for more efficient use of the available bandwidth.

I’ve been given a software defined receiver. Thanks, Brian! It’s an SDRplay RSP2pro. This is a fantastic piece of kit.

G4NSJ - SDRPlay RSP2 pro

It wasn’t my intention to check out the terrible interference at my QTH, so I was amazed to see this interference all over the 80 metre amateur band! The incredibly strong pink lines, S9+ are about 50kHz apart, possibly from ADSL.

Update 13/11/23:

The interference has gone! I don’t suppose I’ll ever know what it was but I don’t care… it’s gone!

G4NSJ - SDRplay RSP2pro 80 metres

Below is the SDR with a high pass filter in line. This attenuates the entire medium wave band, 500kHz to 1.7MHz, by 50dB or more. The reason I’m using a filter is because medium wave stations on my Miniwhip active antenna are incredibly strong.  So strong that they break through on the short wave bands. Our local medium wave transmitter is 5.8 miles away, line of sight. Yes, the SDR does have a built-in filter but I’m using the external one as I prefer it. In fact, I often have both switched in.

SDRPlay with medium wave filter

I also use the high pass filter on my Lowe HF150 communications receiver.