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> I think one problem I see with it is that ordinary smart phones won't work because they transmit at around 100mw and they won't reach that altitude, you will

by raldi 12y ago

> I think one problem I see with it is that ordinary smart phones won't work because they transmit at around 100mw and they won't reach that altitude, you will need an earth station From the article: "When Loon started, Google was testing a system that delivered Internet service to antennas on people’s homes. Mathe explained that this was due at least partly to technology limitations. Project Loon is now capable of sending signals that can be picked up by the smaller antennas on phones."

zw123456 12y ago
Picking up is one thing, getting the signal back from the phone with it's small antenna and low power transmitter seems problematic. But perhaps they have solved that somehow. At those distances, I am guessing the uplink would be very limited due to this. Keep in mind, that cellular carriers over time want the signal of each phone reduced. The reason is that for cellular, to get the capacity up, you want to have more cell site, each site re-uses the same spectrum of the site next to it, so if all the phones had higher power they would all be interfering with each other. They just are not designed to go those kinds of distances. Most cell radii is in the 1 - 5 mile type of range usually. Again, for capacity reasons. In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones").
- sangnoir 12y ago
  > In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones"). Citation needed. What makes you think newer phones have less transmission power than old brick phones? The working range of a cell site (the range which mobile devices connects reliably to the cell site).. is between between 50 to 70 km (30–45 miles)[1] 1. https://en.wikipedia.org/wiki/Cell_site#Range https://en.wikipedia.org/wiki/Cell_site#Range

by raldi 12y ago

zw123456 12y ago

Picking up is one thing, getting the signal back from the phone with it's small antenna and low power transmitter seems problematic. But perhaps they have solved that somehow. At those distances, I am guessing the uplink would be very limited due to this. Keep in mind, that cellular carriers over time want the signal of each phone reduced. The reason is that for cellular, to get the capacity up, you want to have more cell site, each site re-uses the same spectrum of the site next to it, so if all the phones had higher power they would all be interfering with each other. They just are not designed to go those kinds of distances. Most cell radii is in the 1 - 5 mile type of range usually. Again, for capacity reasons. In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones").

sangnoir 12y ago
> In the early days when there were fewer towers spaced farther apart the phones had more power (remember the old "brick phones"). Citation needed. What makes you think newer phones have less transmission power than old brick phones? The working range of a cell site (the range which mobile devices connects reliably to the cell site).. is between between 50 to 70 km (30–45 miles)[1] 1. https://en.wikipedia.org/wiki/Cell_site#Range https://en.wikipedia.org/wiki/Cell_site#Range