[aprssig] Balloon Tracking Question

Ted11 tedlists at hullar.com
Tue Mar 1 13:39:25 EST 2011

Ah, thanks for clarifying this, everyone.  The original cell phone tracking
solution failed due to phone hardware, we think, and not network confusion.
But, good to know it is both a dumb idea, likely to be ineffective, AND
possibly illegal.  I'm convinced not to do that again!  APRS is more fun



-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Steve Noskowicz
Sent: Saturday, February 26, 2011 10:51 AM
To: Andrew Rich; TAPR APRS Mailing List
Subject: Re: [aprssig] Balloon Tracking Question

--- Andrew Rich wrote:

> In some cases it might be ok to use
> You could SMS it once it has landed to see where it is

Thanks Andrew, but ...On board is not a good idea.  Not even SMS, please!

  FCC/agency aside, there *is* a technical reason.  For the same reason
Andrew states below.  When a cell phone is on, it is communicating with
sites.  Cellular *means* that one frequency, used in one cell, is *re-used*
many times over in other cells of the same system because you only
(normally) get into one cell site using that RF (or code) channel.

  The cellular system design depends on you being stronger in one or two
cell sites and virtually non-existent in all the other sites. Each time you
get stronger in one site (of the same system)the system wants to hand you to
that site.
  Your frequency/code is used in other sites all over the *same* systen (and
near-by systems) and you will lock them out at altitude and possibly confuse
the system. 
  I wasn't in the system software end of thing, so I can't comment whether
they consider the effects of high altitute phones when writing system
software.  In some areas, like Denver, where you can be in the foot hills
and cover a larger area, they must have hooks for this.  

  It will interfere in many cities away and different carriers.  You may not
notice a thing, but systems will choke in places.

  Also, at altitude the unit will most likely be transmitting at its highest
power level, not that you'll notice or care...  CDMA works that way, without
going into detail, and makes matters their worst..

 Bad carma.  Kinda like APRS beaconing every 6 seconds on .39 at altitude...

Cheers, Steve, K9DCI

> The reason they dont want you to use them up high is it confuses the 
> network
> Most mobile networks are cellular. They rely on the device being down 
> and low
> If you start seeing more of the network than you should, you start to 
> get lots of handovers etc
> Helicopters are a classic example.
> They give them a UHF to phone patch in some cases.
> ----- Original Message ----- From: "Keith VE7GDH" <ve7gdh at rac.ca>
> To: "TAPR APRS Mailing List" <aprssig at tapr.org>
> Sent: Sunday, February 27, 2011 3:59 AM
> Subject: Re: [aprssig] Balloon Tracking Question
> > Jason KG4WSV wrote...
> > 
> >>> I strongly recommend a backup; cellular
> >> 
> >> Operating a cell phone at high altitudes is a
> violation of FCC regulations.
> > 
> > I don't think Dave was suggesting that the cell phone
> go along for the ride
> > on the balloon. I believe he meant it as a backup for
> the ground teams - hi!
> > 
> > 73 es cul - Keith VE7GDH
> > --
> > "I may be lost, but I know exactly where I am!"
> > 
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> > aprssig at tapr.org
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