[aprssig] APRS on Smart Devices [WAS: APRN news from Dayton!]

Wes Johnston, AI4PX wes at ai4px.com
Tue May 24 14:42:49 EDT 2011

All this talk of using cell phones and infrastructure.....

It's funny.... a concept which is so simple to us... a multicast beacon
message.... is so far out of the realm of cell phone users...  They can
grasp SMS messages.  But they are so accustomed to directed messages, the
whole "cellular broadcast" thing was quite difficult to explain to my office
mate.  The idea that you can send ONE message from the tower and it will
show up on 1000 cell phones all at the same time!! Imagine!  Questions like
"do I have to sign up?" "how does it know I'm in the area if I'm away from
my home area?"  sheesh....

The world needs more geniuses with humility because there are so few of us

On Tue, May 24, 2011 at 14:32, Stephen H. Smith <wa8lmf2 at aol.com> wrote:

> On 5/24/2011 9:37 AM, Julian, G4ILO wrote:
>> I understand and agree with you Gregg but as a user of Lynn KJ4ERJ's
>> APRSISCE in Windows Mobile and also an owner of several APRS RF
>> devices I find myself in something of a dilemma. Do I use APRS over
>> cellular and get all these improved features or do I stick true to the
>> spirit of the hobby, use the radio and accept the limitations of the
>> radio devices and the bandwidth?
> The smart phone types seem to also forget that cellular "wireless" depends
> on VAST amounts of infrastructure - you must be within 5 miles or so of a
> cell site, for all these neat gadgets with their fractional-watt
> transmitters linked to low-performing hidden antennas  to work.     (It
> seems to be impossible now to get a cell phone with an actual exposed whip
> antenna or external antenna connector. )
> Our clunky old low-bit-rate narrowband radios transmit 10s of watts (or
> more) into real antennas, results in vastly more robust long-distance
> communications.
> I recently attended a seminar on conventional land mobile radio vs
> broadband "4G" LTE for public safety comms.   An interesting take on the
> differences I had never heard brought up before was contrasting the energy
> density per Hz of bandwidth (which ultimately determines the SNR at the
> receiver and data throughput achievable).    35 watts in a 20 KHz bandwidth
> for FM LMR vs a one-third-watt smeared out across 10 megahertz.for LTE.
>  The implication was that for comparable coverage area for the user in a
> large metro police dept or county sheriff's dept, you would require 10-20
> times (!) the number of base station sites for LTE broadband; i.e. they
> would basically be building another cellular network.
>  APRS over cellular is as much ham
>> radio as Echolink on a computer (or cellphone) and I think many of us
>> would be quite scathing of someone who claimed he made a ham radio
>> contact because he called someone up on Echolink.
> A lot of people seem to forget that the original intent of EchoLink was to
> interconnect RADIOs in different  regions together over the Internet.
> Several years ago, I saw a posting somwhere reporting that the author of
> EchoLink now regretted implementing the local-user-in
> front-of-PC-mike-&-speaker mode of EchoLink rather than keeping it strictly
> a radio-to-radio setup like IRLP.   Providing the local user mode reduced
> EchoLink to being essentially a hams-only version of Skype or Google Voice.
> -------------------------------------------------------------------------------
> --
> Stephen H. Smith    wa8lmf (at) aol.com
> EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
> Skype:        WA8LMF
> Home Page:          http://wa8lmf.net
> =====  Vista & Win7 Install Issues for UI-View and Precision Mapping =====
>    http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7
> *** HF APRS over PSK63 ***
>   http://wa8lmf.net/APRS_PSK63/index.htm
> "APRS 101"  Explanation of APRS Path Selection & Digipeating
>  http://wa8lmf.net/DigiPaths
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