Earth-Venus-Earth, Venus Bounce or EVE!

Earth-Venus-Earth, Venus Bounce or EVE!

I have been reading about Moonbounce ever since I was an SWL, but came across Venus Bounce or EVE only a few days back. That was from a post by KL7AJ on QRZ. Being quite interested in astronomy from school days, I was quite intrigued about Venus Bounce, not because I am likely to go for it, but because of the fact that I first read about amateur radio from astronomy books while at school. You may know that Venus is the hottest planet in the solar system with temperature of 867°F or 464°C. Even mercury which is the nearest to sun has a lower temperature! The inital attempt at Venus Bounce was from NASA at JPL, way back in 1961 using 85 foot diameter dishes.

It was necessary in those days, to determine the exact position of Venus before they lauched probes to it. They received strong radar returns six and a half minutes after sending the signal. Several hundreds of observations followed in the next two months and that was the first Venus Bounce, though not exactly from radio amateurs! It is mentioned that if they had not found the exact position of Venus by this experiment, the Mariner 2 probe which was Earth’s first successful interplantary mission way back in 1962, might have missed Venus by more than 100,000 miles!

Yesterday N4LMM posted another article on Venus Bounce by radio amateurs, that was also long back, but relatively recent, I would say. That was on EVE by AMSAT-DL in 2009 using a 20 m dish from Bochum on 2.4 GHz. They had used Fast Fourier Transform, popularly known in short as FFT with an integration time of 5 minutes for receiving EVE signals. The reflected signals were clearly visible after an integration time of 2 minutes.

A corresponding news item on ARRL website gives more details on the experiment. AMSAT-DL team had a transmitter generating about 6 kW CW on 2.4 GHz. You may note that 2.4 GHz band is the one currently used for uplink to Qatar Oscar 100 Geostationary Amateur Radio satellite. It is also the popular Wi Fi band, which would be more familar to all tech minded persons. Venus Bounce signals were sent from a ground control station at Sternwarte observatory in Bochum.

EVE signals had travelled about 100 million km and had a round trip delay of about 5 minutes. This was a landmark success for radio amateurs as it was over 100 times further than the Moonbounce which is now not that uncommon. We have a few who achieved Mounbounce here in VU land as well. Though very high powers of the order of 1.5 kW is needed for SSB contacts on Moonbounce, digital weak signal contacts are possible with much lower powers and even a single Yagi antenna, if you have a ‘big gun’ on the other side with huge power and a large antenna array or dish antenna.

AMSAT-DL had repeated the EVE experiment later for several hours, with good echoes from Venus, using Morse code transmissions. May be because of the high power and the large dish needed, I have not come across a report of EVE contact between two radio amateurs yet, unlike in the case of EME, which is being reported fairly often. AMSAT-DL was actually gearing up for their Mars probe named PA-5 and their ground and command station was cleared for operational use by the success of EVE. Gunter’s space page tells me that AMSAT P5A project has been put on hold after further funding was rejected in 2012.