New blog post: Analysis of the CAMRAS Venus radar experiment. A deep dive into the Earth-Venus-Earth L-band radar experiment done in March by @radiotelescoop, Astropeiler Stockert, the Deep Space Exploration Society, and @OpenResearchIns.
I show how to compute the radar Doppler with SPICE and come up with a Doppler spread model based on an S-band scattering model from Arecibo. I explain why the maximum surface Doppler offset is 8.6 Hz even though the rotational velocity predicts 15.7 Hz.
The signal can be detected both in the Dwingeloo and Stockert 25 m radio telescopes, but the performance of Dwingeloo is poorer. The observed Doppler spread is on the order of ±0.75 Hz, which is a bit less than the spread model I made.
Read more: https://destevez.net/2025/04/analysis-of-the-camras-venus-radar-experiment/
@destevez @radiotelescoop @OpenResearchIns Very cool!
My summary: International collaboration of amateur radio astronomers, at multiple sites, with heritage dishes still in service, bounce radar signals off Venus. They measure the doppler shift, of the reflections from the surface, due to the planet's rotation.
@destevez Do you mean SPICE the circuit simulation software or something else?
Btw do you know if there is a similar free software for RF design? I can add all the non-idealities I want with small ideal inductors and capacitors but it's all still an approximation of the electromagnetic physics that make circuits work.
I mean, the shape of PCB traces can even be used to make antennas, filters, and even flyback inductors/transformers for power electronics!
@Zi7ar21 something else: https://naif.jpl.nasa.gov/naif/
Regarding RF simulation, there is some open source software (qucs and qucsstudio come to mind), but it doesn't reach the capabilities of commercial software.
Daniel Estévez
Ian Jackson
Zi7ar21