DSD (Open Source) with dPMR Decoding and Windows Binaries Released

Digital Speech Decoder (DSD) is an open source program for decoding signals containing digital speech, such as DMR and P25. The open source version has been mostly surpassed in use over the last few years by the closed source DSD+ version. However, work is still ongoing on the open source version, and a recent fork by Louis-Erig HERVE @LouisErigHerve has added support for Digital Private Mobile Radio (dPMR) decoding.

dPMR is an open, non-proprietary trunked radio standard that supports both data and digital voice transmission. A licence free variation for short range communications called dPMR466 uses the 446.1–446.2 MHz band. Other modes allow for efficient peer to peer to peer operation (mode 1), operation with a base station repeater (mode 2), or with a trunking signal (mode 3).  All dPMR signals operate in FDMA mode with an efficient bandwidth of only 6.25 kHz. dPMR is also known as Icom IDAS and Kenwood NEXEDGE.

Code for Louis-Erig's DSD fork can be found on his GitHub, and he has also released binaries for Windows on his website. Over on his Twitter he has also been mentioning that he has been able to get around the basic privacy modes on DMR.

dPMR radios, data stations and repeater hardware.
dPMR radios, data stations and repeater hardware.
Tweet
Share154
Reddit
Vote
Email
154 Shares

DragonOS: DSP and Signal Analysis with Composable-SDR, Inspectrum and an RTL-SDR

DragonOS is a ready to use Linux OS image that includes various SDR programs preinstalled. The creator Aaron also runs a YouTube channel that contains multiple tutorial videos for DragonOS

One of the latest videos shows us how to use composable-sdr and Inspectrum to capture and analyze signals. Both programs are pre-built into the latest version of DragonOS. Composable-sdr is a set of DSP processing blocks for SDRs embedded in Haskell. One thing it does well is allowing users to easily capture and record demodulated signals for later use via the terminal. Inspectrum is a tool for analysing and reverse engineering signals that have been recorded.

In the video Aaron explores many of the composable-sdr examples discussed on it's GitHub readme page. Including analyzing a wav file recorded with Composable-sdr with Inspectrum and demodulating and recording a wideband FM signal. He also mentions how it's possible to create a PMR446 scanner that records up to 16 channels at once, and how decode helicopter FSK data from audio heard on YouTube (which we mentioned in a previous post).

DragonOS LTS DSP and signal analysis with Composable-SDR + Inspectrum (RTL-SDR)

Tweet1
Share48
Reddit60
Vote
Email
109 Shares

Testing the YouLoop on VLF & LF Reception with an Airspy HF+ Discovery

Over on his YouTube channel Frugal Radio has been testing his YouLoop passive magnetic loop antenna on VLF and LF reception with his Airspy HF+ Discovery. In the video Frugal Radio browses the VLF & LF spectrum, making note of some interesting signals, and showing how well the combo receives.

The YouLoop is a low cost passive loop antenna for HF and VHF. It is based on the Möbius loop design which results in a high degree of noise cancelling. However the main drawback is that it is a non-resonant design, which means that it needs to be used with ultra low MDS receivers like the Airspy HF+ Discovery. We have YouLoop stock available in our shop for $34.95 with free worldwide shipping.

Airpsy YouLoop passive antenna review on VLF & LF with an HF+ Discovery and SDR# during storms!

Tweet
Share148
Reddit
Vote
Email
148 Shares

Tech Minds: Testing the OpenEar DMR TETRA ADSB POCSAG Decoder for RTL-SDR

Back in March we posted about the release of OpenEar, a standalone TETRA decoder for the RTL-SDR. Since then OpenEar has undergone massive developments, not only improving upon the TETRA decoder, but adding DMR, ADS-B and POCSAG decoders as well as a waterfall display.

Recently Tech Minds reviewed this software on his YouTube channel. In the video he shows how to download the software, install the rtlsdr.dll file, and run and use the software. He then demonstrates reception of an amateur radio DMR repeater, reception of POCSAG pager messages and finally reception of ADS-B aircraft messages.

OpenEar Digital Decoder - DMR TETRA P25 ADSB POCSAG RTL-SDR

Tweet
Share70
Reddit
Vote
Email
70 Shares

Tech Minds: Decoding GMDSS Maritime Distress Messages

In a recent YouTube video Tech Minds shows how to decode GMDSS (Global Maritime Distress and Safety System) messages which are broadcast on MW and HF. In the video he explains the DSC (Digital Selective Calling) which allows calls to be made to individual ships, a group or all stations. He goes on to demonstrate the YADD GMDSS DSC decoder running via the HF audio piped in from SDRUno and received with an SDRPlay RSPdx.

How To Decode Maritime Distress Messages GMDSS DSC

Tweet
Share50
Reddit
Vote
Email
50 Shares

NanoVNA V2 Now Readily Available for $60 + US Stock Available at R&L

The much awaited NanoVNA V2 is now readily available for around $60 + shipping from the Tindie store. Shipping is noted to begin on June 30th due to a public holiday and you must agree to possible pandemic delays, although feedback from earlier customers indicates that most countries appear to be receiving the packages in good time. You can also add a calibration kit for $10 extra, or a calibration kit and acrylic enclosure for $14 extra.

For US customers R&L Electronics have them in stock in "high end" for $59.95 and "low end" for $54.95 options. The high end option appears to have higher quality cables included. UPDATE: It has been brought to our attention that the stock at R&L is actually from a "clone" manufacturer and the clones do not support the original developer.

We note that the NanoVNA V2 is an open source project created by OwOComm, a research organization with a mission to further "intellectual communism". Therefore any factory is free to produce their own version from the designs, and hence several other versions have already been showing up on marketplaces like Aliexpress/eBay. However, for now it is probably safer to buy directly from the original manufacturers on the Tindie store. This is because according to the developer the quality of the "unofficial" clones that are showing up on Aliexpress and eBay is not yet known. The official version also supports the original developer and funds future software development.

NanoVNA V2 Available for Sale on Tindie
NanoVNA V2 Available for Sale on Tindie

A Vector Network Analyzer (VNA) is an extremely useful tool for radio hobbyists as it allows you to tune antennas, filters, and measure cable loss among other applications. Until recently a VNA would cost hundreds if not thousands of dollars. However, the original NanoVNA brought expensive VNA capabilities to the masses with its low $40 pricing. But the original design was limited to a maximum frequency of only 900 MHz. The new V2 design pushes this maximum frequency up to 3 GHz officially, and unofficially up to 4.4 GHz with reduced performance. It also improves on overall dynamic range and maintains the affordable price.

Tweet
Share92
Reddit
Vote
Email
92 Shares

Building a Remote SSB Receiver with an RTL-SDR, OrangePi and GNU Radio

Over on his blog F1ATB has uploaded a post explaining how he created an RTL-SDR or HackRF based remote SSB receiver controllable with an internet browser. To set this up he uses an Orange Pi One Plus single board computer which runs several GNU Radio based digital signal processing flow graphs. Then a Python server serves a custom HTML and Javascript based web interface with waterfall that can be controlled remotely over the internet. In the post he explains the GNU Radio DSP flowgraphs that he's built, and notes that he will explain the HTML and Javascript side in another future article.

The SSB receiver block diagram
The SSB receiver block diagram
Tweet
Share76
Reddit
Vote
Email
76 Shares

Tech Minds: A First Look at the HackRF Portapack

The Portapack is an add on for the HackRF SDR that allows the HackRF to be used portably without a PC. If you're interested, in the past we reviewed the Portapack with the Havok firmware, which enables many TX features such as POCSAG transmissions as well as various other RX modes.

In a recent video Tech Minds reviews a Portapack clone, which is essentially exactly the same as the original Portapack. In the video he shows how to connect the Portapack to the HackRF, how download the Firmware and flash it to the HackRF. He then goes on to show some of the Portapack RX features in action. In this review he uses the official Portapack firmware, but notes that he will test the third party Havok and Mayhem firmware which have many more features in a future video.

Portapack H1 For HackRF - Ultimate RF Hacker Tool

Tweet
Share64
Reddit
Vote
Email
64 Shares