EMETest & EME Batch SNR Analyser

Documentation — Introduction

Instaler Download - EMETest_v2.02_Setup.exe
UPDATE - EMETest_v2.03_Setup.exe - bug fix from some Yaesu radios. Slightly improved Y-factor options.

Note: in v2.02 There may be a CAT issue with some recent Yaesu rigs (FT-2000, FT-450D, FT-950,FTDX-3000, FTDX-5000, FTDX-1200 and FTDX-9000). These should be fixed in version 2.03. If you have any issues with v2.03, please let me know

Earth-Moon-Earth (EME) operation, commonly called moonbounce, is one of the most demanding modes in amateur radio. Signals must travel nearly 800,000 km, surviving roughly 250 dB of free-space path loss each way. Characterizing a station's receive sensitivity, measuring the SNR of actual echoes, and understanding the noise environment are essential both during initial set-up and for ongoing performance monitoring. The two programs documented here address these tasks directly.

Requirements and Installation

The programs should run on any version of Windows from Windows 7 through Windows 11. It will run on both 32-bit and 64-bit systems. It requires 300-400MB of disk space. This seems like a lot (and is a lot) but most of the space is taken up with essential libraries and ephemeris data. There are something like 15,000 lines of actual code.

It can be installed in any directory, but Program Files (x86) is the default and is recommended. All the program, library files, DLL files and ephemeris data will be stored in this directory. Program generated data, logs, ini files etc. are all stored in the users AppData/Local/EMETest directory. This is not something the user can (or should) change.

The program itself does not write anything to any Windows system directory (or the registry). It can be removed either using the uninstaller program, which is in the same directory as the main program, or the EMETest directory and the corresponding user AppData/Local directory. CAUTION - removing the users AppData directory will delete all data files and configuration file, so it is not recommended. If there is a new installer for a new version, it does not require the existing version to be removed. It will overwrite old program files which need to be replaced, but it will not change any data, configuration or log files.

The Programs

EMETest

EMETest is a complete EME echo measurement and station characterization tool. It transmits a continuous-wave tone at a user-set audio frequency, listens for the returning echo after the calculated two-way moon propagation delay (approximately 2.4 s at perigee, 2.7 s at apogee), and computes the signal-to-noise ratio of each echo. It also provides a full suite of noise power measurements for characterizing the receive system — cold-sky, on-moon, sun, and 50-ohm-load references — from which Y-factors can be derived. A real-time FFT spectrum of the averaged echo is displayed alongside a running SNR history.

Key capabilities of EMETest include ephemeris-driven moon tracking (using either the NAIF DE440 SPICE kernels or the PyEphem DE405 fallback), automatic Doppler correction via CAT radio control or audio-frequency tracking with RIT assistance, PTT control via a serial-port RTS/DTR line or CAT command, a continuous-carrier SNR monitor for receive checks while transmitting, and automatic saving of echo audio recordings as WAV files with embedded metadata.

EME Batch SNR Analyser (WAV File Reader)

The Batch SNR Analyser reads the WAV echo recordings saved by EMETest and reprocesses them using the identical SNR algorithm. This allows off-line analysis of a session after the fact, adjustment of analysis parameters, comparison of echoes across a session, and export of results. The program displays an SNR history plot, an averaged echo spectrum, individual per-echo spectra, and a full results table. Results can be exported to CSV and plots saved as JPEG images.

How the Programs Work Together

During an EME session, EMETest operates the station in real time: it keys the transmitter, records echoes, computes SNR, and saves each echo to a dated WAV file in a session subdirectory. Each WAV file carries all the parameters needed for analysis — operating frequency, grid locator, moon azimuth and elevation, propagation delay, Doppler spreading width, and the audio frequency of the echo — embedded as RIFF INFO metadata chunks.

After the session (or at any later time) the Batch SNR Analyser opens those WAV files and recomputes the SNR for each echo. Because it reads the embedded metadata, no manual parameter entry is normally required. The averaged spectrum can reveal a weak echo that is invisible in individual records, and the CSV output provides a permanent log of session performance.

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