# How well can Voyager 1 separate Earth signals from Solar noise these days?

This is a follow-up question to this question and this and this answer. UPDATED: see additional information and discussion below.

As it continues to move farther from the Sun, the angular separation between the Earth and Sun continues to decrease, can it's antenna actually resolve the two and limit the noise from the sun? (seems to be about 0.4 degrees at opposition now) For that matter, how strong IS the noise from the sun relative to earth transmissions, considering the passband of Voyager's electronics - is is it a serious issue to begin with? As earth oscillates in its orbit - is there a seasonal effect?

Besides the mind-boggling large distances an weak signal, the problem I'm talking about here is that - as seen from Voyager 1 (and 2), the earth is only a small fraction of 1° away from the sun, which is a powerful and noisy radio source.

Voyager receives at around 2 GHz, so its 3.7m diameter dish can not separate the two. Even a quiet sun is almost $$\text{10}^6$$ Jy. The electronics is circa 1970, if it has an input bandwidth presented to the front-end of 10MHz, the sun will be a million times stronger than the 20kW Deep Space Network DSN signal.

above: data for the Sun, planets, Pluto, Voyager 1 and Voyager 2, from January 1, 1969 (a good year to start things) until now. Dots are now. Data is from NASA JPL Horizons.

above: Angular separation between the earth and the sun in degrees, as seen from Voyager 1 (heavy, blue) and Voyager 2 (light, green). The dips to near-zero stop happening once the spacecraft left the plane of the ecliptic.

above: example of the type of settings I used to get the data in ecliptic coordinates.

above: Partial screen shots from DSN Now: https://eyes.nasa.gov/dsn/dsn.html, just for fun.

• This has been on the back burner in my mind since you posted. I't starting to bug me so I'll do some research and post an answer when i get some free time. – Andrew W. Mar 7 '16 at 18:48
• @AndrewW. I wouldn't want you to leave Voyager 1 on the back burner too long! If you can just add a short answer with some kind of a link. Am I right - about 0.4 degrees max at opposition? Yikes! Is the sun actually very noisy? – uhoh Jun 4 '16 at 14:59
• I inquired about this at JPL's Space Flight Operations Facility, and they said that they can, and do, still talk with the Voyager probes, usually on a daily basis, and that they still have clear communication with both. – Phiteros Jul 19 '16 at 19:59
• @uhoh I'm not sure about every day, but I see one or both of them on there fairly often, labeled as VGR1 and VGR2. Voyager 1 is talking right now. – Phiteros Jul 20 '16 at 1:21
• Woops, I forgot path loss in the DSN signal the received signal is P.G.A.4.pi/d^2. Here's a link showing an example of link budget from the DSN: propagation.gatech.edu/ECE6390/project/Fall2010/Projects/group7/… – gosnold Jul 21 '16 at 19:05