Grape 2 Personal Space Weather Station
The Grape 2 software defined receiver (SDR) is a key component of the HamSCI Personal Space Weather Station (PSWS). The Grape 2 was designed with specific purposes in mind: Receiving, analyzing and recording of signals from frequency standard stations such as WWV/H and CHU. The PSWS project involves monitoring changes in the Earth's ionosphere through measurements of Doppler frequency shifts on a 24/7 basis.
Ham radio operators and shortwave enthusiasts are encouraged to host Grape 2 SDRs at their stations from now until well after the North American total solar eclipse in April of 2023. Hosting involves providing reliable power, space for an antenna and an Internet connection. Other factors come into play, such as the need for visibility to the constellation of GPS satellites. A Host Interest Survey is now being conducted
A complete description of the PSWS, including an explanation of the science questions driving the need for the Grape 2 (and its little brother, the Grape 1) is available here.
The following is preliminary information. The Grape 2 hardware is in the prototype/testing phase and the software is under development. Features and specifications are subject to change. Anticipated release: Q3, 2023
Anatomy of the Grape 2 PSWS
The Grape 2 is the high performance member of the Grape PSWS family. It is capable of receiving three frequencies simultaneously and it contains an on-board GPS module/frequency standard. It is designed for use on 2.5, 5.0, 10.0 or 15.0 MHz. (Operation on CHU frequencies of 3.33, 7.58 and 14.36 MHz are possible with reduced performance.) The receiver PC board is delivered fully assembled. The complete PSWS system requires the following: Grape 2 SDR, Raspberry Pi 3/4 with USB sound card, external hard drive, power supply and antenna. All components are documented below.
Please note that the Grape receivers are not general purpose software defined receivers (SDRs). They are designed to receive signals only on frequencies pertinent to the research goals.
Images of the bare Grape 2 PC boards: RF board, Logic board, and (not shown) a Raspberry Pi Pico microcontroller board:
Obtaining a Grape 2 PSWS
It is likely that a certain number (less than 50) Grape 2s will be funded through research grants. Should that materialize, complete Grape 2 systems will be built, tested and packaged for delivery to willing hosts at no material expense to the hosts. HamSCI is gaging interest in hosting funded Grape 2 systems prior to the October, 2023 North American solar eclipse. Please complete the following Grape 2 Hosting Interest Survey if you are interested. HamSCI will be looking for sites in specific areas of the US and Canada to best gather solar-eclipse influenced data, so not all site applications will be filled. Everyone's interest is most welcome. And who knows, even if you miss the first cut, additional funding may materialize, allowing HamSCI to expand the foot print of Grape 2 systems for the April, 2024 North American total solar eclipse.
Special Note to Those Who Are Currently operating a Grape 1 receiver (version 1.11 or 1.12):
The data formats will be different in the Grape 2 vs. the Grape1.
- Grape 1s generate CSV files, which could then be graphed or uploaded to the data server.
- Grape 2s will (likely) generate files in the Digital RF format
There are currently research needs for data in both formats. One option to consider would be hosting both Grape 1 and a Grape 2 systems at your location. Two antennas would be required, as the Grape1/2 RF inputs cannot be connected in parallel. If dual hosting would be possible, please so indicate on the Grape 2 Hosting Interest form below.
The Grape Version 2 is being designed by John Gibbons, N8OBJ, Lab Director of the Sears Undergraduate Electrical Design Lab, Case Western Reserve University, Department of Electrical Engineering. Software is being written by Bob Benedict, KD8CGH and Bill Blackwell, AB1XB. Their efforts are being supported by a number of institutions and foundations