Unfortunately patients who are interested in taking a more active approach to their health (such as one member of the team who herself has an implanted defibrillator) do not get to see this data. The team are hoping to use an RTL-SDR to sniff this data which is transmitted in the 402 – 405 MHz ISM band, and then implement a decoder. So far they have successfully been able to capture some signals, and are working on decoding them into data.
By reverse engineering the signal they hope to draw attention to the fact that healthcare providers are not providing real time body data to the patient, preventing them from making their own informed decisions about their health. They write:
It’s all about making informed decisions. A patient knowing about arrhytmias episodes that occured to him/her has the power to change his lifestyle accordingly, by deducing the factors that have influenced his recent attacks and eliminating them – i.e. observing his/her heart condition according to his/her sleep schedule, work rhythm, food choices and participation in sports. As for now, the patients can only hope to get some information on ICD-prevented arrhytmias on scheduled appointments with their doctor, which often occur once a year or even less often. This eliminates any possibility of making informed choices by using patient’s lifestyle data for future arrhythmia episode prevention.
RTL-SDR.com reader Jean Marie Polard (F5VLB) recently wrote in to let us know about a useful document that he has put together which covers beginners amateur radio astronomy. The document includes various introductions to the types of antennas and electronic tools often used in radio astronomy, the software used and an introduction to all the different types of observable objects. There are also a few mentions of the RTL-SDR dongle which is known to be a useful tool for amateur radio astronomy.
The document is available in pdf form in English, as well as in French. If you are looking at getting started in amateur radio astronomy then this is a good starting guide.
The LimeSDR is a new SDR $299 USD currently seeking crowdfunding over on CrowdSupply. At the time of this post the LimeSDR is currently 60% funded, with 29 days left to go. The LimeSDR is a RX/TX capable device, with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and 61.44 MHz bandwidth. From the price and specs, we consider it to be a potential next generation HackRF type device which will have vastly improved RX performance.
From a quick judge of the waterfall images it looks as though the LimeSDR has a very clean spectrum with a low noise floor, which looks good for RX. In future posts Alexandru hopes to test out the transmit capabilties of the LimeSDR, as well as its shortwave RX performance.
It is well known that the NOAA satellites broadcast weather satellite images which can be received and displayed with an RTL-SDR and computer. What is less known is that there is a telemetry beacon that is also transmitted by the same satellites. The telemetry not only contains data such as the current spacecraft time, day and ID, but also contains scientific data from on board instruments such as:
The HIRS/3 and HIRS/4 instruments which is a high resolution infrared sounder which can be used to create a low resolution multi-spectral scan of the earth. (more info)
The Space Environment Monitor (SEM-2) which has a Medium Energy Proton and Electron Detector (MEPED), and a Total Energy Detector (TED). This experiment is used to measure the effect of the sun on satellite communications. (more info)
The experimental DCS/2 transmitter which retransmits signals from 401.65 MHz sea buoys, arctic fox collars, sea ice monitors, weather balloons and more. (more info pdf)
The ARGOS Advanced Data Collection System (ADCS) which amongst other uses is used in research for tracking animal GPS collars around the world.
A satellite tracker is a motorized unit that points a directional antenna towards passing satellites. Most satellites are not in a fixed orbit, and will fly over your head a few times a day and will be receivable for a few minutes, and a directional antenna is usually recommended since the signals can be weak. The goal of the SatNOGS project is to set up various volunteer satellite tracker stations around the world, and network the received data on the internet, so that satellite data is always being received and shared.
Although the tracker works, he admits that there are some problems and that it is probably not as good as the SatNOGS recommended build, which is a more permanent solution. But the SatNOGS build requires access to a 3D printer and higher quality components, so Paul’s solution is a much cheaper solution to implement at least for experimentation.
Over on YouTube user FMDX HUN (Luc1f3rk0) has uploaded a video showing how useful the SDR# IF Processor and Notch Filter Plugin can be when attempting to DX FM broadcast stations. He shows that it can be used to listen to stations that are almost overlapping by cutting out the unwanted signal.
Over on YouTube Leif (SM5BSZ) has uploaded two videos showing some of his tests with the SDRplay. Leif is fairly well known within the SDR community for writing the program Linrad and for doing various tests on different SDR’s on YouTube and his website.
In his first video he first shows that the SDRplay has some susceptibility to USB noise and FM broadcast coming in through the USB cable which can cause some problems. He first shows that a quick fix is to simply coil up the USB cable to create a choke, and that a better fix is to wrap the SDRplay in aluminum foil. Later in the video he also tests dynamic range and reciprocal mixing.
In his second video he shows how he modifies his SDRplay unit to be properly shielded to avoid the USB and broadcast FM interference.
QSpectrumAnalyzer is a Linux based opensource GUI front end for rtl_power or rtl_power_fftw and can be used with an RTL-SDR to scan for signal activity on wide swaths of the frequency spectrum. Recently QSpectrumAnalyzer was updated to version 1.4.0 and the new updates add the following features:
Max peak hold
Min peak hold
Spectrum Persistence (RTSA fosphor-like effect)
Previously we posted about QSpectrumAnalyzers ability to use rtl_power_fftw, which is a much faster version of rtl_power. The new features help make the spectrum view clearer especially when using rtl_power_fftw at a very short interval.