Over on YouTube Mirko Pavleski has uploaded a video showing how he took a US$199 "Pi Terminal-7” 1024*600 All-In-One Module Raspberry Pi" from Elecrow, and combined it with an RTL-SDR Blog V4 to create a portable standalone SDR radio platform.
The build includes a cooling fan, external WiFi antenna, speaker, power switch and physical tuning knob. The built-in Raspberry Pi 4 compute module runs the HamPi image which includes multiple free SDR programs. In the video, Mirko shows the system in action with it running SDR++ and GQRX.
Over on YouTube Amateur Radio VK3YE has uploaded a video showing his 'HF Helper' project. The HF Helper is a tunable HF filter and attenuator that helps improve HF reception when in the presence of strong overloading signals. VK3YE writes:
Using an RTL-SDR.COM dongle (genuine model V4) and a computer with SDR Sharp you can get quite good reception of HF signals. However reception can sometimes be spoiled by overload from signals on or away from the desired reception frequency. The 'HF Helper' presented here can reduce these problems. And you can use it in conjunction with a QRP transmitter to form a simple transmitting station.
RTL SDR HF Helper improves reception
Also as a bonus, in a related video VK3YE also shows the RTL-SDR Blog V4 being used on SDR Touch on an Android phone for portable HF, VHF and UHF reception.
Last week we posted about Alex Petit Jr's 'Project H Line 3D' which is a collection of documents and programs designed to be a beginner's guide to antenna fabrication, reception, recording, software processing, and graphic display of the 21 cm Hydrogen line. The project makes use of an RTL-SDR and LNA as the radio front end.
This week Alex gave an online talk to the Society of Amateur Radio Astronomers (SARA) discussing the project and giving an overview.
Project H Line 3D' is a collection of documents and programs designed to be a beginner's guide to antenna fabrication, reception, recording, software processing, and graphic display of the 21 cm Hydrogen line. The project makes use of an RTL-SDR and LNA as the radio front end.
The Hydrogen Line is an observable increase in RF power at 1420.MHz that is created by natural hydrogen atoms. The Hydrogen line is most easily detected by pointing a directional antenna toward the Milky Way where neutral hydrogen is abundant. Properties of the hydrogen line curve such as its shape and Doppler shift can be used to measure the shape and properties of our galaxy.
Alex's project H Line build is designed to be inexpensive and easy for students to build and set up for drift scans which involve pointing the antenna towards the sky and letting the Earth's rotation drift the Milky Way into and through the view of the antenna.
The project includes a design for a 13-element circular patch feed Yagi that can be built using common materials available from a hardware store. The 13-element Yagi results in about 15dBi gain and a 30-degree 3dB bandwidth.
The software portion of the instructions uses the SDR# IF Average plugin, and uses that to record log files every few minutes. The log files are then converted by an included Java program by Jamison Adcock into a logarithmic dB scale and a format compatible with Rinearn 2D and 3D graphics packages.
If you were unaware, RFNM is a relatively new affordable $299 software defined radio. It is based on the 12-bit LA9310 baseband processor chip, and together with either a 'Granita' or 'Lime' daughter board it is capable of tuning from 10 - 7200 MHz or 5 - 3500 MHz respectively. It is also capable of wide bandwidth - up to 153.6 MHz on a host device like a PC. Recently we gave an initial thoughts review here.
Recently RFNM announced 'Seeve', a version of their RFNM SDR which is 95% smaller, and comes with an MT3812 daughter board and 1W power amplifier built in. Seeve appears to be designed for industrial and commercial customers, via integration into an existing design. Some potential applications they mention include an HD FPV transmitter and as a building block for 5G user equipment.
Pricing is $199 each at 1k quantities or $2k for a devkit.
We've recently come across an X post by Jamie Vital who notes that he has created a site called armsdr.com which is dedicated to tracking which SDR-related software has support for Windows 11 on ARM64.
The Windows OS is most commonly run on x86 and X64 CPU hardware. However, in recent years Microsoft have been pushing to add support for ARM CPUs as well. ARM CPUs are generally lower performance, but significantly more efficient in terms of power use, so they are excellent for battery-powered devices, and so they are commonly used in devices like phones and single-board computers.
Linux is well supported on ARM CPUs, and recently Apple have begun selling computers with ARM CPUs, the Apple M1 and M2. However, Windows support for ARM is still quite lacking, and not very popular. This leaves people who unwittingly purchase a Windows 11 ARM64 laptop mostly out of luck when it comes to running common SDR programs, as programs written and compiled for x86/x64 CPUs will not run on ARM64.
armsdr.com notes that currently only one program, SatDump, has official Win11 ARM64 support. Other programs like rtl_433 and SDR++ have unofficial support, and pretty much every other program has no support, although some may work in emulation mode. But to complicate matters, for emulation mode to work without dropping samples, you need to use librtlsdr drivers that have RAW_IO enabled.
We note that some developers of programs like SDR++ are also refusing to add official Win11 ARM64 support due to the feeling that Windows on ARM has too many issues to be worth supporting. Combined with how low the Win11 ARM64 userbase is, this is most likely the attitude of most developers. Because of these reasons, we strongly suggest avoiding purchasing Win11 ARM64 machines if you want to run SDR software.
Thank you to Alex Petit Jr who wanted to submit 'Project H Line 3D' which is a collection of documents and programs designed to be a beginners guide to antenna fabrication, reception, recording, software processing, and graphic display of the 21 cm Hydrogen line. The project makes use of an RTL-SDR and LNA as the radio front end.
If you were unaware, the Hydrogen Line is an observable increase in RF power at 1420.4058 MHz that is created by natural hydrogen atoms. The Hydrogen line is most easily detected by pointing a directional antenna toward the Milky Way where neutral hydrogen is abundant. Properties of the hydrogen line curve such as its shape and Doppler shift can be used to measure the shape and properties of our galaxy.
Alex's project H Line build is designed to be cheap and easy for students to build and set up for drift scans which involve pointing the antenna towards the sky and letting the Earth's rotation drift the Milky Way into view of the antenna.
The project includes a design for a 13-element circular path feed Yagi that can be built using common materials available from a hardware store. Alex started with a Yagi design using circular director elements but found these difficult to find and fabricate. However, through NEC antenna analysis software he found that replacing the circular elements with more commonly found and easier-to-fabricate square elements had a negligible effect on the antenna's performance, unlocking a cheaper build. The 13-element Yagi results in about 15dBi gain and a 30-degree 3dB bandwidth.
Plate Yagi gives an almost identical Hydrogen line detection as the Disk Yagi
The software portion of the instructions uses the SDR# IF Average plugin, and uses that to record log files every few minutes. The log files are then converted by an included Java program by Jamison Adcock into a logarithmic dB scale and a format compatible with Rinearn 2D and 3D graphics packages.
Videos of talks from the Software Defined Radio Academy 2024 (SDRA'24) conference have recently been uploaded to YouTube. SDRA'24 was hosted primarily as an online conference but was also held physically at the German Friedrichshafen HAMRADIO conference in June 2024.
The talks are slowly being released on YouTube with eight talks released so far on their SDRA'24 playlist. Make sure you subscribe to their YouTube channel to be notified when more talks are released.
Some of the talks of interest that are released include:
FobosSDR by RigExpert
CW Bandwidth Optimization
DMR Tier III base station - TRX in software defined radio
High Res Propagation Measurements
You can find the titles of talks of videos that haven't been released yet on the SDRA'24 programme page. Some interesting yet to be released talks include:
High Resolution Propagation Measurements Using a WSPRSONDE-8 beacon and a RX888 SDR
The PortaPack H4M by OpenSourceSDRLab is a new design of the HackRF PortaPack which comes with various improvements. The PortaPack H4M adds I2C capable GPIO ports, a USB-C connector, a built-in speaker and microphone, a better screen, a proper on/off button that won't easily activate in a bag, flat design for easier storage, and improved charging speed.
The PortaPack H4M is currently available as a bundle for US$152 from Chinese manufacturer OpenSourceSDRLab. The bundle includes the PortaPack H4M PCB, and a HackRF R10c clone. This is exceptionally good value, considering that an original HackRF (just the HackRF without PortaPack) sells for US$319. However, just be aware that by purchasing clones you are not supporting GreatScottGadgets, the original developers of the HackRF.
If you were unaware, the HackRF PortaPack is an accessory for the HackRF SDR that enables portable use, with a display, controls, and onboard processing for direct signal demodulation, modulation, decoding, and encoding, all without needing a computer.
Over on YouTube RocketGod has uploaded a video showing some of the PortPack H4M's new features, how to install the Mayhem Firmware, and then showing it in action with it receiving a few signals.
HackRF Portapack H4M - Getting Started Guide
We've also seen another video by sn0ren that also introduces and shows the PortaPack H4M in action.
