Not if you exploit the stars gravitational lensing: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.188.1145&rep=rep1&type=pdf http://citeseerx.ist.ps

Not if you exploit the stars gravitational lensing: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.188.1145&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.188... A mobile phone antenna (and power) might be well enough then.