On 08/05/2016 05:21 PM, Stephen A. Lawrence wrote:
No more stationary than a satellite. As far as I know, fixed-position
satellite dishes work just fine. Get the altitude about right, get
the azimuth sort of in the right direction, and the reflector produces
some gain, which is what you need.
The signal's strong enough that you don't need a super high gain
antenna, so it doesn't have to be aimed directly at the satellite --
or airplane, in this case. A small dish isn't all that directional,
anyway; its diffraction spread is pretty substantial.
If you're using a 6 meter dish, on the other hand, it's something else
again. It's got a much tighter pattern, and you'd better be aiming it
carefully.
FWIW the Satnet dishes were about 6 meters, as I recall. That was a
project at BBN 'way back when, for providing a packet switched network
in the sky back in the 80's and 90's. The satellite was in
geosynchronous orbit, so it was easy to track, which was a good thing;
with a dish that big and very high frequency signals, over a few tens of
thousands of miles it's almost as tight as a laser. (Or ... maybe they
were 9 meters. Not sure. It was a long time ago.)
At least that's how I understand it.
On 08/05/2016 05:15 PM, MJ wrote:
"small towers and dishes" ? Will the plane be stationary?
Mark Jordan
On 05-Aug-16 17:28, Stephen A. Lawrence wrote:
Thanks -- that makes sense.
On 08/05/2016 02:26 PM, Jed Rothwell wrote:
Ah, here we are:
"With Aquila, we've designed a new aircraft architecture, one that
can support staying in the air for months at a time. Aquila is
solar powered, and when launched, it will create a 50-km
communications radius for up to 90 days, beaming a signal down to
the people in that area. This signal will be received by small
towers and dishes that will then convert it into a Wi-Fi or LTE
network that people can connect to with their cellphones and
smartphones."
https://code.facebook.com/posts/993520160679028/building-communications-networks-in-the-stratosphere/
In other words, the airplane replaces the infrastructure between
towers, and it also allows for smaller towers. Probably cheaper
ones too.
It says they want to reduce communication costs by an order of
magnitude.
- Jed
