Category: Amateur Radio

TechMinds: Using Public Online SDRs without SDR Hardware

This weeks video on the TechMinds channel explores the various online web SDRs that are available to access for free. Accessing these online SDRs does not require any hardware apart from a PC and internet connection, although of course you are then receiving signals from a different location to yourself. 

In the video he shows how to access the SDR# Spy Server Network which mostly consists of Airpsy and RTL-SDR units, the SDR-Console V3 Server network which consists of a wide array of different SDRs, the browser based WebSDR network which is mostly soundcard based SDRs but also RTL-SDR and other SDRs, and finally the KiwiSDR network which is made up of KiwiSDRs.

Using Software Defined Radio Without SDR Hardware - WebSDR

RSGB Talk: How To Check and Report VDSL RFI with an SDR in the UK

Back in April we posted a video from Tech Minds where he showed us how to use special software combined with an SDRplay RSPdx to detect and report VDSL interference on the HF bands. VDSL or Very High Speed Digital Subscriber Line is an internet connection technology that runs over old copper phone wires allowing for a fast broadband connection. The frequencies used by VDSL are between 25 kHz to 12 MHz, and for VDSL2 up to 30 MHz. Unfortunately the frequencies used can result in high amounts of radio interference from RFI radiating from the copper phone lines which is a major problem for HF amateurs and short wave listeners.

Recently John Rogers (M0JAV) presented a talk via the UK amateur radio organization RSGB. In the talk he explains how VDSL works, why it causes RFI and how to check for VDSL RFI using an SDR and the Lelantos software. He also shows how he drove around with a magnetic loop antenna looking for VDSL RFI sources in his neighbourhood. He then goes on to call out for more volunteers in the UK to submit RFI reports to Ofcom as they responded that they won't do anything about the interference unless there are more complaints. 

The RSGB EMC Committee (EMCC) has been investigating VDSL interference since 2014. As the number of installations has risen to over 30M the interference level at amateur radio stations has also increased. The majority of radio amateurs are now impacted by this problem.

In the May 2020 RadCom we outlined how to detect and estimate the level of interference. This can be done by inspection of an SDR spectrum display or by taking a recording and then using a SW package—developed by Martin Sach of the EMCC—which identifies the VDSL signature in the recording and shows how many different VDSL lines are causing the problem and what their relative strengths are.

This talk demonstrates what to look for and how to use the tools to find out if you have a problem yourselves. We hope this will help you respond to our call for action and complain to Ofcom about the level of RFI you are subjected to.

John Rogers, M0JAV
Chair EMCC

RSGB Tonight @ 8 - How to check for VDSL RFI with John Rogers, M0JAV

The Silphase R1 SDR Receiver

Thanks to Thomas' SWLing Blog for bringing to attention the Silphase R1 SDR receiver. This is an upcoming high performance HF SDR receiver being manufactured in the EU by a Polish company called Silphase. The R1 appears to be targeting premium SWLer customers with a price of US$1199. However, they note that by the end of 2020 they will have a 25W transceiver option, and later a 100W transceiver option. The SDR is currently available for preorder only and the sign up form can be found at the bottom of their website.

The Silphase R1 comes with a 5" touch screen that shows a spectrum display, has dual VFO's, four speakers and a metal alloy enclosure. It also comes with a built in telescopic antenna, but external antennas can be connected with the F connector. The tuning range is just the HF bands from 0.1 - 30 MHz and the ADC resolution is 16 bits.

Rendering of the upcoming Silphase R1 HF SWLing SDR

TechMinds: Building a 3D Printed 2.4 GHz Dual Feed Helix for QO-100

The Bullseye LNB that we have in our store is great for receiving the QO-100 amateur geostationary radio satellite which is available in some parts of the world. However it cannot be used to transmit to the satellite. Over on his YouTube channel Tech Minds shows us how to build a transmit helix antenna that connects to the Bullseye or other suitable LNB, resulting in a dual feed antenna.

The antenna that was built is based on DO8PAT's "Ice Cone Feed" design. The design requires some 3D printed parts for the mount and housing, as well as a copper wire helix, metal reflector and copper matching strip. The Bullseye fits onto the back of the helix mount. Once mounted on a dish Tech Minds shows that he was able to make contact with a friend via the QO-100 satellite with good signal strength.

2.4 GHz Dual Feed Helix Antenna For QO100

Step-by-step Guide to Creating a GNU Radio Based QO-100 SSB Receiver

Thank you to M Khanfar for submitting his video that shows a step-by-step tutorial on building your own SSB receiver in Windows GNU Radio for QO-100 satellite reception.  His tutorial includes adding several tuning sliders in the GNU Radio GUI as well.

QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it has allowed amateur radio operators to use a spare transponder. Uplink is at 2.4 GHz and downlink is at 10.5 GHz. We note that we are selling a "bullseye" LNB in our store which allows most SDR dongles to be able to receive the signal with high frequency accuracy.

GNU-RADIO QO-100 SSB Receiver

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

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

Talks from the 2020 HamSCI Convention (Held Online)

HamSCI is an organization dedicated citizen radio science and specifically the "publicity and promotion of projects that advance scientific research and understanding through amateur radio activities". Recently they held their HamSCI 2020 workshop online, and the videos are now available on the Ham Radio 2.0 YouTube channel. Several of the projects mentioned in the talks involve the use of software defined radios.

Come join HamSCI at its third annual workshop! Due to restrictions caused by the COVID-19 Coronavirus, this year's workshop will he held as a virtual, eletronic workshop. The meeting will take place March 20-21, 2020 using Zoom Webinar Services hosted by The University of Scranton in Scranton, PA . The primary objective of the HamSCI workshop is to bring together the amateur radio community and professional scientists. The theme of the 2020 HamSCI Workshop is "The Auroral Connection: How does the aurora affect amateur radio, and what can we learn about the aurora from radio techniques?" Invited speakers include Dr. Elizabeth MacDonald, NASA Scientist and founder of Aurorasaurus, Dr. James LaBelle, Dartmouth Space Scientist and expert on radio aurora, and Dave Hallidy K2DH, an expert in ham radio auroral communication.

One talk discusses the HamSCI personal weather station project, which is an SDR and Raspberry Pi based solution that monitors HF signals like WSPR, as well as characterizing HF noise, detecting lightning and ionospheric disturbances.

HamSCI 2020 Overview of the Personal Space Weather Station and Project Update

Another talk discusses the TangerineSDR, which is an open source SDR currently in development by TAPR. The goal of the TangerineSDR is to be a sub $500 SDR with a focus on space science, academic research as well as general amateur use. 

HamSCI 2020 TangerineSDR Data Engine and Overall Architecture

The rest of the talks can be found on the Ham Radio 2.0 YouTube playlist.