Category: Airspy

Frugal Radio: Testing a Loop on Ground Antenna with an Airspy HF+ Discovery

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

Observing the NML Cygni Red Supergiant Star with an Airspy Mini SDR and Home Radiotelescope

Job Genheniau's projects have been featured several times on this blog in the past for imaging the Milkyway and other astronomical objects like supernova's and protostar regions with a 1.8m radiotelescope dish and RTL-SDR or similar SDR.

In his latest achievement Job has noted that he has had some limited success in observing  NML Cygni with his dish and an Airspy Mini SDR. NML Cygni is a 'red hypergiant' star situated within the Cygnus constellation, and it is one of the largest stars by radius known. Prior observations have found that it exhibits a spectral line at 1612.231 MHz.

Job's setup consists of his 1.5m dish (extended to 1.8m with mesh) on a rotor, a custom feed tuned for 1612 MHz, a 0.47dB NF low noise amplifier, an RF filter and an Airspy Mini SDR. Observations were made in SDR# and plotted with Excel.

The NML Cygni hypergiant is difficult for amateur's to observe, and Job notes that he is not aware of anyone previously observing it with a 1.8m dish. He notes that he had 20 failed attempts, but 5 recordings that stood out as possible successes.

However, ultimately Job has been unable to claim that the star was successfully observed, but his results to appear to show some possible success. He notes that some of the uncertainty stems from the fact that on some recordings he observed the peak at the expected -25 km's blueshift expected from the star, however other recordings had the peak at the wrong blueshift.

Job's full report on his observations can be found in this PDF document.

The NML Cygni Red Hypergiant observed with 1.8m dish and Airspy SDR.

Frugal Radio: Listening in to Live Theatre Wireless Microphones with an SDR

In one of his latest videos, Rob from the Frugal Radio YouTube channel gives us an interesting alternative way to enjoy a theatre show by demonstrating what he heard on his Airspy SDR when taking it to a Christmas theatre show. In a modern theatre show the actors and actresses typically wear hidden wireless microphones and earpieces, allowing their voices to be amplified and instructions from the producers and directors to be heard. If close enough, these devices can easily be picked up with a SDR and antenna.

In his video Rob explains what sort of radio devices and frequencies are used at the theatre, and despite a few set backs he manages to listen in on these devices from the lobby and from just outside the theatre complex. 

Some of the things he hears includes backstage instructions from the directors and production team and of course audio from the performers, including backstage conversations.

2021 SDR Guide Ep 12 : SDR Theatre fail with my AirSpy R2 and RTL-SDR dipole kit

SDRAngel Features Overview: ADS-B, APT, DVB-S, DAB+, AIS, VOR, APRS, and many more built-in apps

SDRAngel is a general purpose software defined radio program that is compatible with most SDRs including the RTL-SDR. We've posted about it several times before on the blog, however we did not realize how much progress has occurred with developing various built in plugins and decoders for it.

Thanks to Jon for writing in and sharing with us a demonstration video that the SDRAngel team have released on their YouTube channel. From the video we can see that SDRAngel now comes stock with a whole host of built in decoders and apps for various radio applications making it close to an all-in-one SDR platform. The built in applications include:

  • ADS-B Decoder: Decodes aircraft ADS-B data and plots aircraft positions on a map
  • NOAA APT Decoder: Decodes NOAA weather satellite images (in black and white only)
  • DVB-S: Decodes and plays Digital TV DVB-S and DVB-S2 video
  • AIS: Decodes marine AIS data and plots vessel positions on a map
  • VOR: Decodes VOR aircraft navigational beacons, and plots bearing lines on a map, allowing you to determine your receivers position.
  • DAB+: Decodes and plays DAB digital audio signals
  • Radio Astronomy Hydrogen Line: With an appropriate radio telescope connected to the SDR, integrates and displays the Hydrogen Line FFT with various settings, and a map of the galaxy showing where your dish is pointing. Can also control a dish rotator.
  • Radio Astronomy Solar Observations: Similar to the Hydrogen line app, allows you to make solar measurements.
  • Broadcast FM: Decoding and playback. Includes RDS decoding.
  • Noise Figure Measurements: Together with a noise source you can measure the noise figure of a SDR.
  • Airband Voice: Receive multiple Airband channels simultaneously
  • Graves Radar Tracker: For Europeans, track a satellite and watch for reflections in the spectrum from the French Graves space radar. 
  • Radio Clocks: Receive and decode accurate time from radio clocks such as MSF, DCF77, TDF and WWVB.
  • APRS: Decode APRS data, and plot APRS locations and moving APRS enabled vehicles on a map with speed plot.
  • Pagers: Decode POCSAG pagers
  • APRS/AX.25 Satellite: Decode APRS messages from the ISS and NO-84 satellites, via the built in decoder and satellite tracker.
  • Channel Analyzer: Analyze signals in the frequency and time domains
  • QSO Digital and Analog Voice: Decode digital and analog voice. Digital voice handled by the built in DSD demodulator, and includes DMR, dPMR and D-Star.
  • Beacons: Monitor propagation via amateur radio beacons, and plot them on a map.

We note that the video doesn't show the following additional features such as an analog TV decoder, the SDRAngel "ChirpChat" text mode, a FreeDV decoder and several other features.

Black Friday Sales on Airspy and SDRplay Products

Black Friday is upon us again. This year we were not expecting any major sales as the component supply chain crisis has meant that many electronic products, including SDRs are very low in stock. However, there are two great sales that we have found:

Airspy

Airspy is holding a 25% off sale for this years Black Friday event. Discounts should track across most of their distributors and their main direct sales platform on iTead. On our own store we resell the YouLoop and have also discounted it there, however stock may be backordered by a few days (discount only available via direct sales, or via Aliexpress).

Airspy HF+ Discovery: $169 $126.75
Airspy Mini: $99 $74.25
Airspy R2: $169 $126.75
SpyVerter: $49 $36.75
YouLoop: $34.95 $26.21

Airspy are also holding a #Freebie promo via Twitter.

Airspy Sale Banner

SDRPlay

Direct sales from the SDRplay website appear to have no discount and the RSP1A is backordered until Jan.Feb, but Ham Radio Outlet are holding a site-wide sale including their SDRplay stock.

SDRplay RSP1A: $119.95 $99.95
SDRplay RSPdx: $239.95 $199.95
SDRplay DUO: $279.95 $239.95

Did you find any other great Black Friday sales? Please let us know in the comments. Unfortunately this year due to low stock we will not be holding our own sale for our products, but over the next year as the situation hopefully improves we hope to drop prices naturally.

Frugal Radio: Choosing a “Step Up” Software Defined Radio

In this weeks Frugal Radio episode Rob explores some low cost "Step Up" radios that for a moderately higher price, can give improved receiver performance when compared to RTL-SDRs .

In the video Rob overviews and compares the Airspy Mini ($99), SDRplay RSP1A ($119), Airspy R2 ($169) and the Airspy HF+ Discovery ($169). He discusses their differences such as the tuning ranges, bandwidths and ADC bit depths and why these parameters matter.

Choosing a "Step Up" Software Defined Radio (SDR)

Lightweight Windows Software uSDR Updated to Version 1.4.0

Back in July we posted about the release of Viol Tailor's "uSDR" software, which is a lightweight general purpose multimode program for Windows which supports the RTL-SDR, Airspy, BladeRF, HackRF and LimeSDR radios. Recently Viol has updated the software to V1.4.0. The new release brings SDRplay support, and various performance and GUI improvements listed below.

The software can be downloaded from SourceForce.

  • customizable tool panel behavior (fixed, floating, undocked)
  • SDRPlay frontend support (API v.2.13)
  • RTL-TCP streaming interface support, presets quick switch (server, port, description)
  • high precision Wav IQ file play back
  • support RIFF 8, 16, 24 and 32 bits integer, 32 bits float, FR64 file formats for playback
  • recognize Wav IQ file central frequency for play back
  • frequency offset (shift) for x-verters
  • swap IQ (invert spectrum) option
  • improved FFT spectrum calculation and visualization
  • waterfall color map range may be changed manually on the spectrum window as well as on tool panel, also included the auto scale option
  • color map palette can be customized and fast switched, palette presets are included
  • FIFO buffer size (IQ history time) may be changed on the fly, all memory allocations are under hood, no losses of previously stored history 
  • pass band may be attachment to global frequency as well as to local baseband frequency or to screen position
  • squelched threshold control and level indicator for demodulation (in addition to adjustable spectrum threshold detector)
  • stereo FM demodulator
  • low latency audio
  • frequency manager, groups and interactive markers, visualize, edit, navigate, tune the pass band
  • spectrum and waterfall popup menus
  • improved GUI controls
  • "fine tune" option: set pass band to rounded frequency (spectrum right click)
  • statistics visualization window
uSDR aka microSDR. A lightweight SDR receiver program from Windows.

SDRSharp Guide V3.0 Released

Paolo Romani (IZ1MLL) has recently released version 3.0 of his SDRSharp PDF Guide which we posted about last in March of this year. As before the document is a detailed guide about how to use SDRSharp, which is the software provided by Airspy. While intended for Airspy devices, SDRSharp also supports a number of third party SDRs, including the RTL-SDR, and it is the software we recommend starting with when using an RTL-SDR.

The guide is now 61 pages long, and covers all the settings, UI customization, included and third party plugins, and use of some external decoders.

SDRSharp Guide