![]() If the beacon is not in the list of known beacons, it’s named ‘unknown’ and stored as such. If the frequency directory does not exist yet for the newly processed frequency file, it is created (with correct file permissions 664) and the data then stored there. ![]() Manufacturer Part NumberĪlso at 00:00:00 UTC, a crontab job for the user pi kicks off a python program to check the data file for corruption and to rename, process and move a new version to the correct directory for submission to the central node server. Instructional screenshots for OS installationįolder of python scripts to set up and run nodeĮlectronics BOM with Digikey part numbers Naming conventions, file structures, descriptions By comparing the received frequency to a precise local oscillator, such as a GPS-disciplined oscillator (GPSDO), a proxy measurement of the shift in ionospheric height may be obtained. When the virtual height falls, the path length decreases and the received frequency increases. ![]() As the virtual height at the point of reflection rises, the path length increases the wavefronts of the carrier are stretched farther apart and the received frequency drops. 1 shows a simplified model, assuming a single hop propagation mode. This carrier frequency is shifted when it reaches a receiving station according to the path it takes through the ionosphere. These stations typically transmit extremely precise carrier frequencies, which allow them to be used as beacon stations for remote sensing. In the United States, stations WWV in Fort Collins, CO and WWVH in Kauai, HI transmit on 2.5, 5, 10 and 15 MHz. These are stations run by governmental and laboratory organizations which transmit coded and audio time announcements. The Grape’s task is to enable Doppler measurements of time standard stations. 2: the narrowband Low-Cost PSWS, called the Grape Receiver, which is the subject of this paper and the wideband SDR-Based PSWS, called the TangerineSDR. There are two variants of PSWS systems, as shown in Fig. These receivers form the first iteration of the Low-Cost Personal Space Weather Station network. At the time of writing, several of these receivers have been deployed across the United States and are actively collecting data. When compared over long periods and across distributed networks of stations, the resulting data yield insights on greater spatial and time scales. Grape receivers can be easily constructed and deployed by amateur scientists in order to gain a deeper understanding of variations in radio propagation in their local environment. ![]() Here, we provide documentation for a low-cost intermediate frequency receiver, the Grape Version 1, which is designed specifically for measurements of North American time standard stations. ![]() However, typical shortwave receivers cannot be put to ordinary use while these measurements are being taken, do not have standardized signal chains, and are generally too expensive to be purchased for the sole purpose of taking Doppler measurements. Quantitative Doppler measurements of high frequency (HF) time standard stations, used in bottom side ionospheric sensing, have been accomplished using existing radio hardware belonging to volunteers in distributed campaigns. Crowd sourced data collection among the international community of amateur radio operators and shortwave listeners has great potential for addressing problems of under-sampling in the geospace system. ![]()
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