link budget, Open Research Institute

Greetings all!

This past weekend, Venus was at the closest to Earth in their respective orbits. This means that bouncing signals off of Venus and hearing them back on Earth had the highest probability of success. ORI participated with modeling and link budget work. The event happened this past weekend, 22 March 2025.

Congratulations to Dwingeloo and Stockert for successful signal detection. This is an achievement that has not been accomplished in the amateur radio satellite service since 25 March 2009 by AMSAT-DL at Bochum Radio Telescope in Germany. Given that the anniversary of this remarkable achievement is tomorrow, then the news we are able to share is delightful indeed.

Here are some initial reports:

Here is Dr. Wolfgang Herrmann’s Earth-Venus-Earth (EVE) report on the Society of Amateur Radio Astronomers (SARA) email list

https://groups.google.com/g/sara-list/c/lOSa102nmpc

Here is Dwingeloo’s report from their website (very nice mention of ORI!)

First Venus bounce with the Dwingeloo telescope

Deep Space Exploration Society (DSES) attempted detection with a transmission, but the signal was not received.

If you would like to join the effort to make the most of the October 2026 inferior conjunction, then the time to join is now.

The goal is to move beyond detection into communication. This challenge is very difficult.

ORI’s link budget work can be found here: https://github.com/OpenResearchInstitute/documents/blob/master/Engineering/Link_Budget/Link_Budget_Modeling.ipynb

ORI’s goal for this document is to continue its educational and predictive role for interplanetary communications in space, and to spark interest and activity in EME and EVE efforts. People that want to do amateur radio satellite communications need resources that explain the communications channels of space in an accessible and citizen-science friendly manner.

If you know someone that might want to be a part of this mission, then please direct them to https://openresearch.institute/getting-started

Or, file an issue or pull request to improve the link budget. We value your opinions and expertise.

We’re hard at work on an Earth-Venus-Earth (EVE) link budget for amateur sites attempting Earth-Moon-Earth (EME) style bounces off Venus for the upcoming inferior conjunction (when Venus is closest to Earth).

Here’s the Jupyter Lab notebook: https://github.com/OpenResearchInstitute/documents/blob/master/Engineering/Link_Budget/Link_Budget_Modeling.ipynb

We need to set the right final communications “margin” or “adverse tolerance”. 0 dB isn’t enough of a detection threshold. We’ve gotten suggestions ranging from 3 dB to 10 dB to 13 dB. This makes a big difference in the number of integrations for some of the modes.

The amount of Doppler from Venus’ rotation makes a difference too.

If you have insights on either or both and would like to help, please weigh in.

Would you like to test out Zadoff-Chu sequences at your EME station? That would be a huge help too.

For this upcoming attempt, the frequency is 1296 MHz. For the next attempt, 580 some odd days after that, the anticipated frequency is 2304 MHz.

Tag: link budget

Successful Earth-Venus-Earth Amateur Communications

Earth-Venus-Earth Link Budget Work