Project

Radio propagation studies using WSPR

Goal: Use the Weak Signal Propagation Reporter network with my own receivers and transmitters to (a) study HF band radio propagation particularly to and from the Polar Regions and (b) evaluate and improve receiver and antenna performance.

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Gwyn Griffiths
added a research item
The wsprnet.org database provides a very good service for collecting, and making available, some 2.4 million spots from about 2500 reporters on a typical day. Its web page query tool, and those of third parties that scrape data from wsprnet.org, fulfill the needs of very many users. However, for users seeking to glean additional information from their own WSPR spots, or from those of a wider community, the tools provided by a relational database and a data visualization package become necessary. This paper outlines the rationale behind the WsprDaemon time series database, our initial experience with Influx as the database, and the reasons for moving to TimescaleDB. The system's architecture is described, highlighting resilient data gathering with user and server caches, an ability to handle delayed spot reporting, and a close coupling to Grafana as the visualization package. Three examples of Grafana Dashboards illustrate this approach and the utility of the results in providing users with a richer set of graphics to help them understand what WSPR spots tell them about propagation and their own installations and noise environment.
Gwyn Griffiths
added an update
My colleague Rob Robbinett presented the work that he has done alongside Glenn Elmore and me on "Estimating LF–HF Band Noise While Acquiring WSPR Spots" at the 2019 ARRL/TAPR Digital Communications Conference. Our work provides useful information for people developing new software defined radio (SDR) implementations and for those interested in using low cost SDRs as personal space weather systems.
@Gwyn Griffiths
 
Gwyn Griffiths
added a research item
This document contains working notes, results of experiments, snippets of code and suggested methods for estimating noise in conjunction with the reception of Weak Signal Propagation Reporter (WSPR) transmissions and specifically in conjunction with wsprdaemon - a multiband, multi-receiver WSPR data gathering, decoding and reporting script written by Rob Robinett, AI6VN. Using the free SoX cross-platform audio editing software, here implemented on a Raspberry Pi, we begin by exploring SoX's built-in RMS measurement code to estimate noise within the gaps between WSPR transmissions. We then go on to use the frequency analysis tools in SoX to test and then implement a selective frequency domain approach to noise estimation that can run during WSPR transmissions not just within the gaps. Using data gathered at KPH, Point Reyes, California, a site with very low man-made noise, and at a low noise site on Maui, Hawaii, we compare the results from the two methods on bands from 17–160m. We consider these early results to be encouraging and that others may well benefit from using the extended wsprdaemon, especially with well-calibrated SDR receivers. We end by outlining our next steps towards ensuring data accuracy, quantifying uncertainty, making the KPH data publically available in real time and working the calibration back to the antenna.
Gwyn Griffiths
added a research item
This short report is a part of an on-going study between Gwyn Griffiths G3ZIL and Mike Gloistein GM0HCQ on the analysis of 10MHz Weak Signal Propagation Reporter (WSPR) amateur radio transmissions received on the UK polar research vessel RRS James Clark Ross. The first focus is a comparison of the patterns in spots per day with latitude between the 2017 and 2018 northbound meridional transect voyages between 50˚S and 50˚N. The second focus is an analysis of WSPR transmissions on the 10MHz amateur radio band from DP0GVN located at Germany's Neumayer III research station on the Ekström Ice Shelf, at 70˚ 41'S 8˚16'W that were received on the 2018 voyage from Stanley, Falkland Islands to Southampton, UK in March–May. Reception Signal to Noise (SNR) levels and band open times are compared with those from a propagation prediction model and the influences of solar and geomagnetic conditions on reception are described and discussed.
Gwyn Griffiths
added an update
This report covers two topics:
1. A comparison of WSPR spots per day received on the RRS James Clark Ross in 2017 and 2018.
2. A detailed analysis of WSPR spots received on the ship from a WSPR transmitter at the Neumayer III Research Station, Antarctica (DP0GVN) including a comparison with the predictions of a propagation model.
 
Gwyn Griffiths
added an update
This report analyses a consistent set of observations of WSPR signal reports from a single platform, the RRS James Clark Ross, from a latitude of 51˚ in the UK to 81.75˚N north of Svalbard.
The key points are:
1. The ~100-fold decrease in the number of spots per day between the latitudes of ~60˚N and ~80˚N that is due to both the longer paths to the senders in Europe (who form the majority of senders) and the requirements for very settled geomagnetic and ionospheric conditions for propagation to locations north of the Auroral Oval.
2. We conclude that, for the Arctic, at locations north of the Auroral Oval, the use of low power, low data rate WSPR-like ionospheric HF radio data telemetry is not practical.
3. WSPR transmissions from CG3EXP on board the MV Polar Prince Canadian C3 expedition made for the uncommon occurrence of a WSPR sender and receiver north of the Auroral Oval. WSPR spots were only decoded when geomagnetic field fluctuations and solar wind parameters of proton density, dynamic pressure and proton speed were at a minimum. Whether the sparse decodes were due to inadequate SNR or whether due to excessive auroral flutter was not established.
5. The statistics on spots received within the Auroral Oval from this expedition has enabled a reassessment of the WSPR spot data from RV Araon to the Chukchi and Beafort Seas in 2016 when only three spots were received over eight days. An empirical statistics-based analysis shows, within an order of magnitude, that given the geomagnetic and ionospheric conditions and the geographical distribution of senders relative to the RV Araon's location that only receiving three spots would not have pointed to equipment problems.
 
Gwyn Griffiths
added a research item
This study has gathered and analysed a consistent set of observations of WSPR signal reports from a single platform, the RRS James Clark Ross, from a latitude of 51˚ in the UK to 81.75˚N north of Svalbard. The key points are: 1. The ~100-fold decrease in the number of spots per day between the latitudes of ~60˚N and ~80˚N that is due to both the longer paths to the senders in Europe (who form the majority of senders) and the requirements for very settled geomagnetic and ionospheric conditions for propagation to locations north of the Auroral Oval. 2. Following directly from these observations we can provide a clear answer to our study's key question, "Could low power, low data rate High Frequency (5-18MHz) ionospheric radio provide an effective low-cost alternative to satellite communications for data-gathering from remote stations in the Polar Regions?" For the Arctic, at locations north of the Auroral Oval, the use of low power, low data rate WSPR-like ionospheric HF radio data telemetry is not practical. Despite the potential spatial diversity of receivers the data throughput would be low and unreliable and would be most unlikely to meet the needs of users. 3. Comparison of observed and predicted SNR for UK and Eastern North America senders to the two study areas in the vicinity of Tromso and at 75˚–77˚N showed reasonable agreement for the times of band opening and closing. However the SNR predictions overstated the SNR and band open times to the study area between 80˚–81.75˚N. This is understandable, as the predictions do not take into account geomagnetic disturbance or solar wind parameters. 4. WSPR transmissions from CG3EXP on board the MV Polar Prince Canadian C3 expedition made for the uncommon occurrence of a WSPR sender and receiver north of the Auroral Oval. Reception, or more strictly, a decoded WSPR signal, was only possible when geomagnetic field fluctuations and solar wind parameters of proton density, dynamic pressure and proton speed were at a minimum. Whether the sparse decodes were due to inadequate SNR or whether due to excessive auroral flutter was not established. 5. The statistics on spots received within the Auroral Oval from this expedition has enabled a reassessment of the WSPR spot data from RV Araon to the Chukchi and Beafort Seas in 2016 when only three spots were received over eight days. An empirical statistics-based analysis shows, within an order of magnitude, that given the geomagnetic and ionospheric conditions and the geographical distribution of senders relative to the RV Araon's location that only receiving three spots would not have pointed to equipment problems.
Gwyn Griffiths
added a research item
Man-made noise on the HF bands is a topic that often crops up in PW, to the extent that Paul Burgess G3VPT recently asked, "Is this the end of Amateur Radio?" While man-made noise is certainly troublesome - we both have suburban locations, G3ZIL in Southampton and G4HZX in Beckenham, South East London - our answer is a resounding "No". Furthermore, our answer is not based on using costly commercial receivers or antenna arrays but on the simple 40m WSPR direct conversion receiver described in April 2016's PW with straightforward dipole and vertical antennas. We've realised, not surprisingly, that it is the antenna and local noise and not the simplicity of the homebrew receiver that were limiting the receiver's performance. This article is the story of our quest to understand and improve HF band signal to noise ratio using information derived from WSPR spots while along the way seeing textbook antenna and propagation characteristics appear in practice.
Gwyn Griffiths
added an update
10MHz WSPR spots were received from 12 May to 30 June. Analysis focuses on senders from UK, USA and Japan to areas off South America, Ascension Islands and Canary Islands. Great disparity in spots/day between southern and northern hemispheres noted.
 
Gwyn Griffiths
added a research item
This informal report gives a descriptive overview of the WSPR spots received at 10MHz on a transect of the RRS James Clark Ross from Uruguay to the UK with a summary of the ionospheric conditions and their effect on reception. Section 4 compares predicted and actual propagation conditions for four exemplar regions: off the coast of South America, near Ascension Island, the vicinity of the Canary Islands, and at Southampton, UK. Section 5 has a brief report on the relative noise level when at sea approaching the UK and when docked at Southampton. Section 6 has a discussion of the results and an outline of future work
Gwyn Griffiths
added a research item
Could low power, low data rate High Frequency (5-18MHz) ionospheric radio provide an effective low-cost alternative to satellite communications for data-gathering from remote stations in the Polar Regions? Our approach to the study question at this feasibility stage is not to transmit data using High Frequency (HF) radio from the Polar Regions but instead to receive existing HF radio transmissions and make the assumption of reciprocity (which we know has limitations) to infer the probable characteristics for transmission in order to better design a series of transmission experiments. This short informal report gives a descriptive overview of the WSPR spots received in section 3 with a summary of the ionospheric conditions and their effect on reception. Section 4 gives a quantitative throughput analysis. Section 5 compares predicted and actual propagation conditions, leading to conclusions for low power low data rate HF sky-wave data communications from this sector of the South Atlantic and west of the Antarctic Peninsula in section 6, together with suggestions for future investigations.
Gwyn Griffiths
added a research item
Could low power, low data rate High Frequency (5-18MHz) sky wave radio provide an effective low-cost alternative to satellite communications for remote data-gathering stations in the Arctic? Use the equipment provided to receive radio amateur Weak Signal Propagation Reporter (WSPR) signals at 10MHz. WSPR provides an existing, effective, communications protocol and a worldwide reporting network that could be a model for a future Arctic data reporting network. With virtually no existing WSPR stations in the Arctic the deployment on Araon provides a valuable learning and evaluation experience for the technology, operations and propagation conditions. The WSPR receiver and processor installed on Araon did work, but only three signals ("spots") were received compared with 6000-15000 that would be expected with this receiver in the UK over a similar period. This disappointing performance is analysed in detail and recommendations for further work outlined.
Gwyn Griffiths
added a project goal
Use the Weak Signal Propagation Reporter network with my own receivers and transmitters to (a) study HF band radio propagation particularly to and from the Polar Regions and (b) evaluate and improve receiver and antenna performance.