[amsat-bb] Re: Cell Phone in Spce

Michael Heim kd0ar at sbcglobal.net
Wed Feb 4 11:48:08 PST 2009

I recall doing a broadcast remote where I was engineering the remote from a single engine aircraft.  At about 5000 feet or so, I lost all cellphone functionality because I was getting into  too many cell sites at the same time and the system locked me out (thats the best explanation I could come up with).  Even if there was enough signal from that distance, I doubt it would work for that reason.

Michael Heim
Chief Engineer, Forever Broadcasting
New Castle PA

--- On Tue, 2/3/09, Tony Langdon <vk3jed at gmail.com> wrote:

> From: Tony Langdon <vk3jed at gmail.com>
> Subject: [amsat-bb] Re: Cell Phone in Spce
> To: "Kelly Martin" <kelly.lynn.martin at gmail.com>, "Dave" <dave at mynatt.biz>
> Cc: AMSAT-BB at amsat.org
> Date: Tuesday, February 3, 2009, 9:51 PM
> At 01:33 PM 2/4/2009, Kelly Martin wrote:
> >Cell phones need about -95 dBm received to work at all
> (and really at
> >-95 dBm about all you get is network beaconing, with no
> ability to
> >actually place a call).  Typical cell transmit powers
> rarely go past
> >one watt, and I think the cell base stations rarely go
> much over ten
> >watts (per channel).  I think you'll find that
> there's too much path
> >loss for that to work to even LEO, notwithstanding the
> fact that cell
> >tower antennas typically have radiation patterns that
> send virtually
> >all the signal into terrain, that being where the cell
> phones are.
> Some systems (GSM being the main example) have a distance
> limitation, 
> of how far you can go from the base station, without losing
> sync due 
> to propagation delay.  Suffice to say this is well short of
> any LEO, 
> even the ISS.
> 73 de VK3JED / VK3IRL
> http://vkradio.com
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