Thank you to Nobu who has submitted news about the release of his new product, a machined aluminum enclosure for the Airspy HF+ Discovery. The Airspy HF+ Discovery comes by default in a plastic enclosure. Although the HF+ Discovery does not need a metal enclosure to perform well in terms of PCB noise rejection, a metal enclosure gives the product a much more premium feel, and aesthetically looks great. Nobu also mentions that the metal enclosure may help with heat dissipation.
The product is only available on Amazon Japan and may show no stock for international customers. If you are outside of Japan, to be able to purchase you may need to use a Japanese market buying agency, many of which can be found online.
@lambdaprog, creator of Airspy products mentions that this enclosure may help with Airspy HF+ Discovery devices running 24/7.
The RF shielding is already achieved using a small anechoic chamber made from the PCB itself, the metal can, and some EMI absorbing material. So, I won't expect much changes in that aspect. However, this alu case can help with the heat dissipation in systems running 24/7/365.
The KK5JY Loop on Ground (LoG) antenna is a 15 feet per side square loop designed for reception of HF and lower. It simply consists of an isolation transformer and wire that as the name implies is placed somewhere on the ground in a square loop like shape. It is cheap and easy to build and compact in that it does not take up any usable space.
In his latest video Rob from the Frugal Radio YouTube channel tests out this antenna with his Airspy HF+ Discovery SDR. He uses a bit of wire lying around, and a low cost 9:1 Balun from NooElec as the isolation transformer. With this antenna he was able to pick up signals in the USA and all the way over to Australia from his home in Canada. NDB signals were also receivable.
2022 LoG (Loop on Ground antenna) for SDR radio tested on Airspy HF+ Discovery SDR KK5JY HAM radio
Over on YouTube Sarah is back this week with a new video on her channel SignalsEverywhere. In this video she shows how to decode HF WEFAX (weather fax) images using an Airspy HF+ Discovery software defined radio with a YouLoop antenna. HF weather faxes are daily weather chart images transmitted as an analogue signal over the HF bands by coastal stations. They are mostly used by ships at sea.
First Sarah shows where to find a lists of WEFAX frequencies and schedules for her area, and then goes on to demonstrate a WEFAX signal being received and decoded using SDR#, VB-Audio Cable and the FLDIGI decoder.
Decoding HF WEFAX Weather Fax with SDR Software Defined Radio | Airspy HF Discovery
AIS stands for Automatic Identification System and is used by marine vessels to broadcast their GPS locations in order to help avoid collisions and aide with rescues. An RTL-SDR with the right software can be used to receive and decode these signals, and plot ship positions on a map.
Jasper notes that his software was intended to be a platform for him to experiment with different receiving model algorithms. On the GitHub readme he explains how he's experimented with a coherent demodulation model that estimates the phase offset, a non-coherent model which is similar to what most existing decoders use, a modified non-coherent model with aggressive PLL, and an FM discriminator model which assumes the input is the output of an FM discriminator.
The readme goes on to show some comparison results indicating that the coherent model is the best although it uses 20% more computation time. He also compares AIS-Catcher against some other AIS decoders like AISRec and rtl-ais, showing that AIS-Catcher appears to be comparable or better than AISRec, which is one of the most sensitive decoders available for SDR dongles.
A Windows binary is provided on the releases page and compilation instructions for Linux are provided on the Github Readme.
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!
At his house W1VLF found that his solar inverter was causing huge amounts of interference on the HF bands, essentially making any hope at receiving shortwave or amateur radio signals impossible on his Airspy HF+ Discovery . However, over on his YouTube channel he's demonstrated a solution that allows him to almost completely cancel the noise.
The solution involves using a Timewave ANC-4 noise canceler, which is as analog noise cancelling device available from the manufacturer for US$209.95. To use the device you also need a noise probe which can be a small loop antenna. The noise probe is connected to the ANC-4 and placed near the source of the noise, which in W1VLF's case was just on the solar inverter enclosure mounted on the outside of his house. Then by tuning the gain and phase knobs on the ANC-4 the noise can be cancelled out of the signals received by the main antenna.
In the video W1VLF demonstrates how effective noise cancelling with the ANC-4 can be by showing the before and after results with his Airspy HF+ Discovery.
Kicking Solar inverter noise in the A$$ with noise cancelling
The World Radio TV Handbook (WRTH) is a directory book (or CD) of world radio stations on LW, MW, SW and VHF broadcast FM which is released yearly. Along with the directory, the WRTH authors often review the latest shortwave listening hardware including SDRs and give out awards to the best units.
Last year the Airspy HF+ won the WRTH 2019 award for best value HF SDR, and this year the Airspy HF+ Discovery wins the 2020 award. The award comes with a glowing review in the magazine (the review is freely accessible) noting the HF+ Discoveries' "spectacular combination of performance and versatility" as well as it's affordable price point.
PiSDR is a Raspberry Pi distribution that is pre-loaded with multiple programs for various software defined radios. It currently supports RTL-SDR, LimeSDR, PlutoSDR, Airspy, and as of the most recent update the Airspy HF+. The currently pre-installed software packages include SDR Angel, Soapy Remote, GQRX, GNURadio, LimeUtil, and LimeVNA.
Recently version 3.0 was released, and this new version adds a few new features like Desktop shortcuts, Raspberry Pi 4 support, Airspy HF+ support and documentation.
The latest image can be downloaded from the PiSDR website at https://pisdr.luigifreitas.me. It can be burned to an SD card in the same way that you would with a standard Raspbian installation. This is a great image to start from if you're experimenting with RTL-SDRs on a Raspberry Pi, as it means that you don't need to go through all the steps of installing the drivers and software like GQRX and GNU Radio which can take a long time to install.