At 12:09 4/12/00 , Ron Lee wrote: >I am not sure this is correct. The Iridium antennaes are more vertical >than earth facing and we see reflections from other satellites like >Superbird-A. > >Ron Ron, we see reflections off the Solar panels of abandoned geostationary satellites BECAUSE the solar panels are no longer pointing at the Sun, as they are on working satellites. If you work out the numbers , knowing the solar panel areas , you will see that the solar panels are not very reflective. In fact to respond to a remark of Alexander, they have always been so. The gain in efficiency comes from improvments in converting photons to hole-electron pairs, not any changes in the bulk reflectivity ( 12.5%) which is governed by the refractive index change from vacuum or air, to silicon( gallium arsenide). The Iridium MMA's are pointed downward at about 30 degrees off the vertical, to receive transmissions. As has been discussed several times a surface pointing sraight down, like the antennae backplane of the globalstar satellites cant produce solar reflections either. Tony Beresford ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
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