Dwingeloo-Stockert EVE experiment Doppler shifts?

[Dave Typinski]

Here's a nice Earth-Venus-Earth experiment between Dwingeloo and Astropeiler
Stockert.

https://www.camras.nl/en/blog/2025/first-venus-bounce-with-the-dwingeloo-telescope/

Does anyone know how the Doppler CSV files available at the raw data link were
generated?

https://data.camras.nl/venus/

The Python code for the signal analysis is there, but not the code for how the
Doppler shift files were generated. Would be interesting to see how they
processed the various available ephermerides to obtain the expected Doppler
shifts and rates.

Wolfgang?

Thanks!
--
Dave

[fasleitung3]

Hi Dave,
I am afraid I can only give a partial answer as all the Doppler
calculations were performed by Thomas Telkamp from the Dwingeloo team.
The basic tools that were used were Astropy and Spiceypy, the latter
being a Python wrapper to the Spice toolkit from NAIF (
https://en.wikipedia.org/wiki/SPICE_(observation_geometry_system))

I can get in touch with Thomas to ask whether he can provide more
details.

Understanding the Doppler shifts and correcting for that was extremely
important for success. Since the return signal was very weak we had to
make sure the energy was concentrated in a narrow frequency band for
sufficient SNR.
We performed a number of test with EME to make sure we had everything
on track.

I am looking forward to the next inferior conjunction of Venus in
October where we plan to repeat the experiment.

Best regards,
Wolfgang

> --

[Peet Denny]

What power was the transmission, I wonder to get to Venus and back and still be detectable.
Sent from my iPhone

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> Hi Dave,

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[Dave Typinski]

Hi Wolfgang,

That would be very helpful, thank you. Seeing a real-world example of how he
obtained that data from the Spice kernels using Python would be very useful for
our Jupiter research.

I wouldn't have guessed that the Doppler shift would change so much between
Earth and Venus in only four minutes. Is the correction still called
de-dispersion when it's in the frequency domain instead of the time domain?
Either way, that was a very neat experiment!
--
Dave

[Thomas Telkamp]

Hi Dave,

Good question and thanks for your interest in our experiment. I have added the notebook that generates the .csv files in the same folder (notebook/), hope this helps you.

It is also highly recommended to read Daniel Estévez’ analysis on this topic: https://destevez.net/2025/04/analysis-of-the-camras-venus-radar-experiment/

He verified the Doppler data, and then even improved on our results by creating a better matched filter.

best regards,
Thomas

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[Dave Typinski]

Hi Thomas,

Thank you for uploading the Spice notebook -- and also for the link to Daniel
Estévez' analysis. Both are very helpful.
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Dave

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[fasleitung3]

I believe it was around 1 kW, but again Thomas Telkamp will know the
exact number.
Wolfgang

[Thomas Telkamp]

1 kW indeed.

Thomas

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[Peet Denny]

Seems like an incredible feat to bounce a signal off a rock 40m km away and then receive meaningful and useful signals back using no more power than I use to boil the kettle for a cuppa. 

I can’t imagine the precision needed. 

Sent from my iPhone

On 9 Feb 2026, at 09:24, Thomas Telkamp <tho...@telkamp.eu> wrote:



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