1/ In October 1945 Arthur C. Clarke published an article in Wireless World. It described a communications system of three satellites at altitude of 35,900 kilometers whose period exactly matched the earth's rotational period. I met with him only one time. celestrak.com/columns/v04n07/ 
2/ Orbits have different eccentricities – a measure of how circular (round) or elliptical (squashed) an orbit is. Non geostationary orbits (NGSO) can look quite odd at first like this one Boeing would like to use for a satellite system at Ka and V band.
licensing.fcc.gov/myibfs/downloa…
licensing.fcc.gov/myibfs/downloa…
3/ I try to include some science in my tweets since you can't understand business today without it. Another example would be propagation of radio waves at V band (40 to 75 GHz). Even oxygen creates problems at this frequency as does rain. Everything (almost) is a trade off.
4/ Example: NGSO satellites in a high orbit.
Good: Less satellites needed to have continuous coverage; can see more of earth allowing capacity to be focused with beam steering more easily.
Bad: greater signal delay and harder to create a link due to distance.
Good: Less satellites needed to have continuous coverage; can see more of earth allowing capacity to be focused with beam steering more easily.
Bad: greater signal delay and harder to create a link due to distance.
5/ Sometimes a technology works around what seems like a physics barrier.
Example: MIMO exploits "spatial diversity" since each pair of transmitter-receiver antennas use a different wireless channel, for each of which the Shannon limit still holds. waveform.com/blogs/main/5g-…
Example: MIMO exploits "spatial diversity" since each pair of transmitter-receiver antennas use a different wireless channel, for each of which the Shannon limit still holds. waveform.com/blogs/main/5g-…
6/ Each satellite orbit and frequency has favorable and unfavorable attributes.Customers will want multi-orbit and multi-frequency solutions. With modern electronics and software there's no reason for customers to select just one solution. Having the best of all is best. Mars tho
6/ If you are an investor and you don't understand the science at the level in this thread you can't understand something like the Starlink satellite system which provides most of the value of SpaceX. You don't need to do the math, but you do need a base level of understanding.
7/ Valuing any communication network requires an understanding of science. The laws of physics are not just guidelines. They can be your friend or enemy. news.google.com/articles/CAIiE…
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