Tagged: HF

TechMinds: Testing the RadioBerry an HF SDR Transceiver Raspberry Pi Hat

The RadioBerry is a HF transceiver board designed to be used as an add on 'hat' for the  Raspberry Pi. It uses the same AD9866 chip as the Hermes Lite 2 SDR which gives it a 12-bit ADC with one RX and one TX channel, a maximum bandwidth of up to 384 kHz, and an operating frequency range of 0 to 30 MHz. 

In the video TechMinds shows how to connect and setup the Radioberry software on the Pi and how to stream from the Pi to SDR-Console V3 on a PC. He goes on to demonstrate the Radioberry receiving HF signals, noting that the performance is good, although he uses an Ethernet connection and Pi 4 for best performance.

TechMinds notes that he will test the transmit functionality in a future video, once he receives a preamp designed to be used with the Radioberry.


Decoding HFDL ACARS with a WebSDR and PC-HFDL

In the previous episode Rob from the Frugal Radio YouTube channel showed us how to decode HF ACARS using PC-HFDL and an HF capable SDR such as the Airspy HF+. In that episode he mentioned that it is possible to decode HF ACARS using a WebSDR as well.

In this weeks episode, Rob shows us how to do just that, making use of WebSDR receivers and the PC-HFDL software. Like the previous episode we see how to plot the aircraft HF ACARS position data on Google Earth and how to read and interpret some example messages received.

Decoding HFDL ACARS with a WebSDR and PC-HFDL

Frugal Radio: HFDL HF ACARS Decoding Tutorial

In Rob's latest episode of his excellent aviation communications series on his Frugal Radio YouTube channel he shows how to decode aircraft HF ACARS (HFDL) using a software defined radio. HFDL is short for "high frequency data link", and is a method aircraft use for sending text and data communications to ground stations. It is an alternative to VHF or satellite ACARS communications methods.

In the video he shows how he's been able to receive HFDL from all over the world using a simple HF dipole antenna and an Airspy HF+ Discovery. He goes on to show how to find HFDL signals, and how to decode signals using SDR# and the PC-HFDL software. Finally he shows examples of aircraft received, and how to interpret some of the information being received, including location information.

How to decode HF ACARS (HFDL) free with your SDR - Monitoring Aviation Communications Episode 8

Frugal Radio: Turning Scrap Wire into an Effective HF Dipole

In this weeks video Rob from his Frugal Radio YouTube channel shows us how he's turned an old piece of scrap electrical extension cord into an effective HF antenna for his Airspy HF+ SDR. The scrap wire is combined with a US$15 NooElec 9:1 balun which helps improve the impedance match of the antenna. He then stretches the dipole out through his backyard and then hooks it up to his Airspy HF+.

The results show good reception across the 20m, 80m, 40m amateur radio bands, as well as on HF ATC aircraft communications, US coast guard weather information broadcasts and the AM broadcast band.

I made an HF Dipole for free! Reception was good on my AirSpy HF+ Discovery SDR!

A Hi-Z to 50 Ohm Impedance Matching Transformer for Improving HF/SW Reception

Thank you to Mitsunobu for writing in and sharing news about the release of his new product which is a Hi-Z (high impedance) to 50 Ohm matching transformer. This transformer allows you to use small antennas such as short telescopic whips for HF/SW reception on software defined radios.

Generally for HF reception you would want to use a full sized antenna, which can be many meters long and certainly not portable. However, by using an high impedance transformer it becomes possible to use smaller portable antennas. Reception with a small antenna and transformer will still be suboptimal compared to a full sized HF antenna, however, if the signals are strong enough the transformer will allow you to receive them decently.

In the tests shown on his blog (in Japanese, use Google Translate) he shows how the transformer adapter can be connected to a small telescopic whip and Malachite DSP SDR for portable use. Later he also shows how the adapter can make our Dipole Kit antenna work well for HF on a RTL-SDR Blog V3 with direct sampling.  

The product is only available via Amazon in Japan. However, Mitsunobu notes that Amazon.jp offers international shipping. He offers the transformer by itself, and a version including a short telescopic whip antenna.

Hi-Z to 50 Ohm Antenna Transformer for HF/SWL

Using an RTL-SDR as a Panadapter with an Automatic Antenna Switcher

Over on YouTube "Gadget Talk" has uploaded a useful video showing how he set up an RTL-SDR V3 based panadapter system to use with his traditional amateur radio. The setup involves utilizing an antenna switcher which allows him to transmit with the RTL-SDR connected to the same antenna. The switch grounds the SDR during transmission, ensuring that the RTL-SDR is not overloaded with the transmit signal.

In the video he also shows how to set up the HDSDR receiver software and the HRD Rig Control software for controlling the hardware radio through the software and vice versa.

SDR Panadapter Using an Antenna Switcher

Tech Minds tests out the YouLoop HF Passive Loop Antenna

Over on YouTube Tech Minds has uploaded a new video where he unboxes and tests a YouLoop HF Passive Loop Antenna with his Airspy. The YouLoop design is also known as a Möbius loop, or noise cancelling passive loop "NCPL". The passive nature of the antenna means that highly sensitive radios will work best with it, however limited results may still be obtained with other radios. The advantages are extremely low levels of interference pickup and high portability.

In the video Tech Minds explains the specifications of the antenna before demonstrating the antenna receiving the HF bands with an Airspy + SpyVerter. He also tests the loop on VHF, demonstrating its ability to receive a distant 2M beacon.

We note that we sell official YouLoop antennas on our store for $34.95 including free shipping to most countries.

YouLoop HF Passive Loop Antenna

SDR# Updates: RTL-SDR Enhanced Mode, AM Co-Channel Canceller for MW DX

Over the past few days SDR# has been updated again adding several new great features. The first is an "RTL-SDR Enhanced" front end driver, which is actually Vasili's front end driver that was released a few years ago. This front end enhances the capabilities of the RTL-SDR as it exposes features like decimation and individual gain control. We note that the current version appears to have a bug preventing enhanced mode from starting, but we expect that it will be fixed again soon. Vasili's File Player has also been added, and this allows for easy playback of RTL-SDR IQ files.

The second feature added recently is an AM Co-Channel Canceller which is could be quite a big feature for medium wave (MW)/broadcast AM DXers. When DXing MW a problem is that you'll often encounter is two stations that are on or almost on the same frequency. This is either due to neighbouring countries not agreeing on frequencies, long range DX antennas picking up further than the intended broadcast range, or from malicious jamming as with the Chinese Firedrake. With a standard radio or demodulation algorithm such a situation makes either both stations impossible to listen to, or only the strongest station will be heard. However, the new AM Co-Channel Canceller plugin in SDR# uses clever DSP algorithms to allow one of those channels to be effectively removed, allowing you to listen to the other station clearly.

Over on the SWLing blog Guy Atkins has written up a comprehensive review and tutorial of the Co-Channel canceller plugin. We've also seen a few examples up on YouTube already, and the video posted below shows user "SDR-radio" in Japan experiencing a South Korean station blocking out a weak local Japanese station. Enabling the plugin allows the weaker station to be heard.

SDR# (SDRSharp): AM Co-Channel Canceller plugin