Thank you to RTL-SDR.com reader André for submitting and sharing with us his QO-100 ground station setup. The setup also includes antennas and equipment to receive HF and VHF/UHF. His setup can serve as an example of a well set up permanent installation.
André's set up consists of a 1.8 meter prime focus dish, Raspberry Pi 4, GPIO connected relay, Airspy R2, Ham-it-up upconverter, coaxial relay for switching between Mini-Whip and Discone Antenna, and FM bandstop filter and a power terminal rail block. The Airspy R2 is used for HF/UHF/UHF reception and the antennas and upconverter are all controlled via a web connected relay system. All equipment is enclosed in an outdoor rated box, and André notes everything has been working well from temperatures range from -10C to 35C.
Inside the satellite dish feed is housed an Adalm Pluto SDR, and a wideband LNA and a USB to LAN converter with power over Ethernet. A small log periodic Yagi serves as the feed. In order to work the wideband DATV band on Qo-100, André' swaps out this feed for a custom feed and brings the PlutoSDR indoors where it is connected to a 120W Spectran Amplifier and modulator.
A few days ago we posted about the upcoming crowdfunding campaign of the MicroPhase AntSDR E200, an SDR that is very similar to the PlutoSDR, but with a much larger FPGA and more stable TCXO. One interesting feature is that it can run PlutoSDR or USRP firmware, allowing it to work with software that supports either hardware.
Over on YouTube Matt from the TechMinds YouTube channel has received an early unit and uploaded a video review.
In the video Matt explains the features and specifications of the ANTSDR E200, shows how to set it up with either the PlutoSDR or USRP firmware, and then demonstrates it working in SDR Console and SDR Angel as an emulated PlutoSDR. He goes on to show how to install and run the USRP UHD firmware, where the ANTSDR emulates an USRP b205mini.
MicroPhase ANTSDR E200 UHD USRP & PLUTO SDR SUPPORT
The AntSDR E200 is a software defined radio from Microphase which will come in two flavors. The first is the 'AD9363" version with 2x2 RX/TX and a 325 - 3.8 GHz tuning range, 20 MHz bandwidth and 12-bit ADC. The second is their higher end 'AD9361' version with 2x2 RX/TX, 70 MHz - 6 GHz tuning range, 56 MHz bandwidth and 12-bit ADC.
The AntSDR E200 is is based on the AD9363 / AD9361 RF SDR chips which are used in many existing mid-range software defined radios like the PlutoSDR, bladeRF and Ettus USRP's.
The design itself is very similar to the PlutoSDR and Errus B205mini, and in fact the developer has ported firmware from PlutoSDR and the Ettus UHD that allows the device to work just like those devices. It is not yet known if the AD9363 frequency range extension hack available on the PlutoSDR, and the bandwidth overclock hack on the bladeRF will be possible with the AntSDR E200 as well.
Pricing is yet to be displayed on CrowdSupply, however the the AD9363 version appears to already be available for purchase on Aliexpress for US$364.25. Update: Microphase have explained that the units on Aliexpress are not officially authorized units and the Aliexpress price is much higher than what they will charge during the crowdfunding phase.
ANTSDR-E200 demo video
Also, over on YouTube DragonOS creator Aaron has already been testing his AntSDR with srsRAN, which is an open-source program that can create 4G and 5G basestations with compatible SDRs like the USRP. Using the modified UHD firmware, Aaron was able to get up and running with the AntSDR E200 very quickly.
Over on YouTube Jon Kraft has been uploading videos explaining some interesting beamforming experiments he's been doing with his PlutoSDR. One experiment shows how to create a DIY monopulse tracker, which is a type of radio direction finding technique.
The PlutoSDR has two RX ports and two TX ports, and in this experiment he uses two directional antennas for the RX and one monopole antenna for the TX. Part 1 of this series explains standard phased array beam forming, and part 2 moves on to explain monopulse with adaptive tracking.
If you were interested in this, check out Jon's other videos on his channel. A recent video explains how time delays work in digital beamforming.
Professor Jason from Harvery Mudd College in California has recently uploaded a 23 lesson video series on software defined radio digital signal processing (DSP) concepts that can be learned with an RTL-SDR, PlutoSDR and GNU Radio.
If you're looking for a University level introduction to DSP this looks like a good hand on approach to learning. It covers concepts from a simple FM radio receove in GNU Radio, to doppler radar with PlutoSDR, to digital modulation, pulse shaping, GPS reception and more.
Over on the TechMinds YouTube channel Matt has been experimenting with using a PlutoSDR for QO-100 amateur radio satellite communications. The PlutoSDR is a low cost RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range (with mods). The PlutoSDR can suffer from frequency instability, especially when warming up, however on the latest model C/D PlutoSDRs it's possible to inject an external clock signal.
In his video experiment, Matt uses a Leo Bodnar GPSDO as an external clock source. A GPSDO is a "GPS Disciplined Oscillator", as it uses the accurate timing information found in GPS signals to create a high quality clock signal. Matt shows how to set up the GPSDO, and how to tell the PlutoSDR to use the external clock.
He goes on to show the effectiveness of the GPSDO with some transmit experiments.
The new pricing is at quite a premium over the original LimeSDR Mini which released in 2017 for US$139, and the standard LimeSDR which released in 2016 for US$249. However we of course must to take into account the extreme inflation of electronic parts pricing that has occurred over the past few years.
Lime Micro have also noted that the standard LimeSDR has also now been discontinued due to the same supply shortages. The standard LimeSDR had 2x2 RX/TX channels and was capable of a bandwidth of up to 61.44 MHz. In comparison, both versions of the LimeSDR Mini are a 1x1 channel product with 40 MHz of bandwidth.
The LimeSDR Mini 2.0 is almost identical to the LimeSDR Mini 1.0, both still making use of the LMS7002 RF transceiver as the main chip and using the same overall design. The only change is an upgrade to the FPGA, which replaces the Intel MAX 10 16k logic gate FPGA with a significantly more capable Lattice ECP5 44k logic gate FPGA.
Given the new pricing, people on the lookout for a new hacker/research/experimenter SDR in this price range might want to consider this brief comparison to find the best suited SDR for your needs:
LimeSDR Mini 2.0- US$399
1x1 channels, 40 MHz bandwidth, 10 MHz to 3.5 GHz, 12-bits.
The La Crosse weather station system consists of a LCD base station, and various wireless sensors. Ryan first discovered that the devices used the 915 MHz frequency band via details written on the device itself. His next step was to open up Universal Radio Hacker and use one of his SDRs to record a packet. URH then allowed him to convert that data into bits for packet analysis. The rest of his post goes into detail on how he set the symbol rate, discovered the preamble and reverse engineered the CRC code.
The next step he took was to generate a spoofed packet generated by URH and transmitted by the PlutoSDR. This allowed him to set the base station display to any temperature that he specified. But he ran into a problem where only the first packet he sent after power up was received. Eventually he discovered that the system sets a randomized interval for each of the transmitters at startup, and data outside of that interval is ignored.
Ryan's post explains his whole though process and progress in detail, so is an excellent study for anyone looking to get into reverse engineering wireless signals.