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.
Over on Reddit u/Xerbot has posted about the release of his new software called "LeanHRPT". When combined with a software defined radio, this software can be used to decode and view HRPT weather satellite images received from satellites such as NOAA, Meteor, MetOp and FengYun. We note that unlike APT and LRPT weather satellite signals which transmit in the VHF bands, HRPT signals are generally at ~1.70 GHz and require a motorized or hand tracked satellite dish to receive. u/Xerbot writes:
LeanHRPT is a flexible, easy to use and powerful set of tools for the manipulation of HRPT data (maybe I could be convinced to add LRPT support).
When used properly LeanHRPT Decode can generate (almost) L1B data usable in actual land/weather observation, or just pretty images :)
You can get it here: https://github.com/Xerbo/LeanHRPT-Decode
The LeanHRPT project also contains LeanHRPT Demod, as you probably guessed, a HRPT demodulator. It features an incredibly high sensitivity as well as being able to do both realtime (through SoapySDR) and offline demodulation (baseband).
You can get it here: https://github.com/Xerbo/LeanHRPT-Demod
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.
This week on the Tech Minds YouTube channel Matthew introduces the "Cloudmarkers" plugin for SDRuno. SDRuno is the official software for the SDRplay RSP line of software defined radios, but the EXTio version also supports the RTL-SDR.
Cloudmarkers is a plugin that allows users to query the online Cloudmarkers database to determine what an unknown signal at the currently tuned frequency might be. The database is created by other Cloudmarkers users, so if you have your own information to add you can add information about particular frequencies to the database for others to query later.
In the video Matthew shows the Cloudmarkers plugin in operation and notes that the plugin can work with both SDRplay SDRs and the RTL-SDR.
Sarah from the SignalsEverywhere YouTube channel is back this week with a video review and demonstration of our RTL-SDR Blog Active L-Band patch antenna, which is designed for receiving Inmarsat and Iridium satellites between 1525 - 1660 MHz with an RTL-SDR or other bias tee capable SDR.
In the video Sarah demonstrates the patch antenna in action running in SDR++, discusses some of the features and compares it against another patch antenna. She goes on to briefly show JAERO receiving and decoding an 8400bps AERO voice channel.
If you're interested, this antenna has also been reviewed by Frugal Radio, Tech Minds, and Mike from SDRplay.
The patch is currently in stock in our store for $49.95 shipped worldwide, or on Amazon USA for US customers. We note that previous problems (as explained in our earlier post) with cracks in the plastic in the latest batch with grey enclosures have been resolved now, and units shipping now are without defect.
Just a few days ago we posted about Job Geheniau's success at radio imaging the Cygnus-X star forming region at 1424 MHz with a 1.9m radio telescope, an RTL-SDR and some additional filtering and LNAs.
Now in his latest post on Facebook Geneniau has also shown that he has successfully imaged Cassiopeia A with the same equipment. Cassiopeia A is a supernova remnant known for being the "brightest extrasolar radio source in the sky at frequencies above 1 GHz" [Wikipedia]. Geheniau writes:
A new observation from JRT. These are driftscans of Cassiopeia A to make a radio plot. Several driftscans are made last week and combined. Always nice to see whats possible with a 1.5-1.9 meter dish. 2 LNA's and a bandpass filter, connected to a RTL-SDR at 1424 MHz. Happy that I got Cygnus complex and now Cassiopeia A which is the second radio source which is possible to receive with this dish.
The dish is fully remote controlled 50 km away.
Job Geheniau - The Netherlands
In the past we've posted many times about DragonOS which is an Ubuntu Linux image that comes preinstalled with multiple SDR software packages. This takes the hassle out of needing to compile and install programs on Linux, some of which can often be very difficult and time consuming to get up and running. Aaron who is the creator of DragonOS also runs a YouTube channel where he provides multiple tutorials and demos of the software installed.
This week on the Tech Minds YouTube channel, host Matt tests out DragonOS in a Virtual Machine and gives a broad overview of what DragonOS is capable of. He shows how to set up VMWare Workstation in order to create the virtual machine, installs Dragon OS, shows what programs are included and demonstrates a few programs in action.
The following was posted to our Crowd Supply page as an update to our KrakenSDR crowd funding project.
Thanks to everyone’s amazing support we were able to fund in less than 24 hours from release! Now, thanks to funding, we can move on to the job of finalizing our batch manufacturing and accelerating development of our codebase.
Please keep in mind we’ve sold almost half of the first batch of 1000 units! So, if you have been hesitating, please get your order in soon since subsequent batches could be susceptible to manufacturing delays.
The design of the KrakenSDR enclosure is coming along nicely and we expect to be cutting the new prototype soon. The image below shows a 3D rendering (the blank space in the middle will contain the logo). The enclosure is a critical part of the KrakenSDR as it helps add thermal mass and cooling ability. Phase drift can occur when the tuner chips experience temperature fluctuations, so adding thermal mass helps to dampen ambient temperature changes significantly. The PCB is thermally connected to the enclosure via a thermal pad. The enclosure, of course, also helps block signals from directly entering via the PCB, which could skew results.
Unfortunately Arrow Antennas have recently informed us that delivery of their five-element, fixed-site, dipole array we mentioned in the campaign text is going to be delayed due to the aluminum shortage crisis in the USA. We’re holding out hope this will be resolved early next year by the time we ship. Please note that this has no impact on the $99 set of five magnetic mount antennas offered directly by us through the campaign.
There have been some concerns that the release of KrakenSDR means support for new developments on our previous product KerberosSDR is abandoned. We have stopped development on the older KerberosSDR code, but we want to clarify that KerberosSDR is fully supported by our new KrakenSDR code, which is a massive improvement.
The new code is designed to be compatible with x-channel Kerberos/Kraken style receivers. So it can support the four-channel KerberosSDR and the five-channel KrakenSDR as well as any DIY system with x-channels. The only change required will be setting the RX channel count in the configuration. The main disadvantage with the older KerberosSDR hardware is that even with the new code, you still will need to manually disconnect the antennas when calibrating (e.g., at startup or frequency retune).
If you have a KerberosSDR, you can try this code out right now by cloning and installing heimdall_daq_rx and krakensdr_doa. Everything, including install instructions and documentation, is in the development branches of our GitHub repo (please note this setup may be a little involved at the moment as the code is evolving rapidly). When the code is fully released, the ready-to-use Pi4 SD card will be usable with KerberosSDR simply by changing the RX channel count.
We have also considered the Android App and are happy to announce that all our previous KerberosSDR customers will receive a license for the upgraded app when it is released too. KerberosSDR customers, please keep an eye on the email address you used with your order for updates on that in early 2022.
This week, the 4.5V bias tees were put through a stress test by powering five wide-band LNAs. This is working beautifully with a 5V, 3A power supply. A 3A supply will be required if you are intending to power an LNA on each port, as the KrakenSDR itself draws 2.2A maximum load when all tuners and the noise source is active.
We have also been testing how the KrakenSDR could be coupled with a small, low power, 10dBm 433 MHz ISM band CW beacon based on the Heltec WiFi Lora 32 hardware, but modified to run the LoRaFox fox hunting beacon software. The range of this low power beacon at 10dBm seems to be roughly three kilometers/two miles with the beacon obscured inside the glovebox of a car. We plan to provide more info on these tests in the next few weekly updates as we think there is an application for similar low power beacons combined with KrakenSDR for local asset, pet, or wildlife tracking.
We are also beginning work on our network mapping solution, which will allow users to run multiple KrakenSDRs in an area with all units uploading data to a central server over the internet. The server will run a web-based version of our Android app, collecting and plotting all bearing data on the same map, and determining a likely TX position. We hope to have a working beta out by the time we ship early next year.
