DOI: 10.5281/zenodo.14159545
title: Annular Solar Eclipse 2023:  recordings of the entire medium-wave AM broadcast band from near Masset, BC, Canada, Part 1

description: recorded by Nick Hall-Patch, VE7DXR

Grid square of location recorded:  CO44aa 

These data files are recordings of the entire medium wave broadcast band (535-1705kHz) made during the annular solar eclipse of 14 October 2024 from 1518UT to 1732UT from near Masset, BC, Canada.   They are part of a set of such recordings made from 13 Oct 1330UT to 15 Oct 1715UT.   Maximum obscuration of the sun was 69% at 1619UT. 

Data files are .wav format, but the archived files are .zip, with about ten .wav files packaged together in each .zip file, using the prefix "VE7DXR-Masset-wideband_125_2125kHz".  As the total files recorded during the solar eclipse exceeded the Zenodo 50GB limit, the remainder of the dataset is found in "Annular Solar Eclipse 2023: recordings of the entire medium-wave AM broadcast band from near Masset, BC, Canada,  Part 2”

The recordings not included here or in Part 2 are available to provide reference data for the eclipse recordings.  Please contact HamSCI at am-eclipse@hamsci.org if you require this data. 

Antenna:   North oriented Beverage, 450' length, unterminated; amplified by DX Engineering RPA-1 at receiver.  

Receiver:  SDRplay RSPdx with RF gain = 20dB and using HDR mode, with center frequency 1125kHz, recording 2000kHz wide passband, using SDR Console v 3.2 build 2643.  Although the RSPdx was not frequency locked, a Bodnar Mini Precision GPS Reference Clock outputting 1705.0000kHz was on site, and its accurate signal was recorded in the data.   Computer time accuracy was determined by Windows NTP server.
description: In the AM broadcast band (535-1705kHz), there are roughly two modes of broadcast station signal coverage, one of which occurs in the daytime, and the other at night. During the day time, signals are propagated by ground wave and not usually heard well beyond 150km from the transmitter. However, at night, an absorptive region in the ionosphere, the D-layer, disappears, allowing signals to refract off higher regions of the ionosphere, and to be heard hundreds and even thousands, of kilometers away from the transmitter. 

The radio stations in this band use amplitude modulation, which requires a strong stable carrier wave, well suited for observing changes in signal characteristics over a time period. During the annular solar eclipse of 14 October 2023, signals were observed changing from daytime to nighttime mode, and then back again as the moon's shadow moved across North America. 

Data Quality:   The recorded .wav data contains a few dropouts (<20 seconds).

Included in these files is an installation file for the universal playback software, SDR Console (“ SDR-Radio V3.3, 64-bit, 2024-02-05_0741.exe” ), to allow playback of the .wav files once extracted; this is courtesy of  Simon Brown, G4ELI, its developer.  The latest version is available at https://www.sdr-radio.com/Console . Instructions for playing back SDR .wav files in SDR Console are found in “OpeningSDRfilesInConsole.pdf” on this site.

There are also reference files to assist in identifying signals heard :

“AM Stations within Umbra 2023 Annular Eclipse.xlsx “, courtesy of Richard Cook KE6EE. 

"US-Canada AMBC List Nov_2023.xlsx", courtesy of Tim Tromp KE8JFM (https://amdxer.com/ambc/ )

“RDMW-2022-v1.2.2.zip”, courtesy of William Scott, WE7W ( https://radio-timetraveller.blogspot.com/ )

"2023-24_IRCA_Mexican_Log.pdf” , courtesy of International Radio Club of America ( https://www.ircaonline.org/ )

Finally,  a copy of Carrier Sleuth software (“CarrierSleuthWindowsMay2024.zip”) is included, courtesy of its developer, Chris Smolinski, W3HFU, along with further instructions for use ( “CarrierSleuthOverview.pdf” ).   This can be used to view .fft files zipped in “VE7DXRMassetCarrierSleuth-Oct13-15.zip” which will provide waterfall visualizations of all carriers for each AM broadcast band channel during the entire recording period.  Carrier Sleuth may also be used to create new .fft files from the data.  The latest version is available at https://www.blackcatsystems.com/software/medium_wave_carrier_display_app.html .