[aprssig] APRS on Android/-IS to RF gating

Gregg Wonderly gregg at wonderly.org
Fri Jan 28 14:20:39 EST 2011

On 1/27/2011 1:26 AM, Greg D. wrote:
>  > From: kd7zwv at peterson.ath.cx
>  > Date: Wed, 26 Jan 2011 22:54:07 -0700
>  > To: aprssig at tapr.org
>  > Subject: Re: [aprssig] APRS on Android/-IS to RF gating
>  >
>  > On Jan 26, 2011, at 8:36 PM, Lee Bengston wrote:
>  >
>  > And, for the gentleman who said something to the effect that we're supposed
> to be doing things with RF (I know it wasn't you, Lee, I think it was Greg), *I*
> thought we were supposed to be communicating. If we weren't supposed to be
> trying new things and communicating in new ways, we'd never have progressed
> beyond spark gap Morse. I know from talking with Bob KB4APR that it's about
> people communicating. Anything we can do to facilitate that, with whatever
> technology, is a good thing in my opinion.
>  >
> As I said, if we use the IS as an accessory to RF, then I'm all for it. No
> objection at all to communicating, and the more different ways we can do it, the
> better. I'm just concerned we might be heading down a slippery slope where we
> put too much focus on the Internet and not enough on the clever things we can do
> in the RF space. When everyone has a 3G cell phone hooked to IS, and spends
> their time watching each other wander, ant-like, around our Retina displays, we
> won't need RF. Until the IS or Cell part breaks, then we'll totally unprepared
> when we're forced to dust off the HT and remember how to turn it on.
> Your example of effectively sending out a CQ via IS for a QSO on 2 meters is an
> interesting yet troubling mix of technologies. I need to let that settle in my
> brain a bit...

I think the key issue, is deciding whether we think RF means ham band, or any RF 
emission.  Clearly cellular devices are using RF.  The main issue for me, is 
that there is no way for a sizeable number of people to participate in 144.39mhz 
in any particular area.  Yet, with the strength and diversity of cellular 
network coverage (when it is working), we can have a ton of participants, and 
covey a lot more information due to the decoupling of layers 5 and above on the 
cellular network.

On 144.39, because all layers are at layer 2, we get no ability to manage 
transmission of information except through "retry" mechanisms that are "iffy" at 

I guess my practical view is that the restrictions on participants on 144.39 is 
making it impossible to have "useful" participation.  We can get a handful of 
people involved on any freq at 1.2kbps only and we need the APRS-IS or some 
other aggregation system anyway.

What I have been concentrating on with my iPad application (APRSNow) is the 
simple fact that I don't have to use the cellular network.  All I need is a 
TCP/IP path from the device to an iGate.  I can carry that iGate around with me 
in the car or use one at home as my gateway to RF. But, because the path out of 
the device is always TCP/IP based, I can "transmit" into the global APRS-IS to 
provide a more global view of my traffic when I need that.

This is the viewpoint that I think we need to focus on.  Applications, I feel, 
need to be independent of any singular "network", not "reliant on 144.39".  By 
stepping back from just 144.39 as a solution and instead focusing on all 
possible paths to RF on 144.39, we can become independent of the "layer 2" 
network by focusing on programmatic interfaces that talk at layer 5, and 
providing mechanisms to get to the right layer 2 network.

Gregg Wonderly

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