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[aprssig] Xastir on Google G1?

Steve Dimse steve at dimse.com
Mon Oct 27 03:37:46 UTC 2008


On Oct 26, 2008, at 10:20 PM, Greg D. wrote:

>
> Anybody know enough about this new toy to know if xastir would be an  
> easy port to it?  With a built-in GPS, it could be an interesting  
> platform.


If you have not used one of the new generation of smart phones that  
started with the iPhone, you will probably be very surprised by how  
quickly it becomes indispensable. With it comes a whole new  
expectation of the content you view on the device/

I don't have specific knowledge of the G1, but I suspect it is not too  
different in general terms from the iPhone. xastir could be ported to  
the iPhone, and probably without too much difficulty, but I'd consider  
it a waste of my time.  Let me see if my experience with the iPhone  
might help you frame your needs a little better.

Sometimes there is a temptation to follow an old paradigm a little too  
long. I was certainly tempted, my original plan was a full APRS client  
on the iPhone. Fortunately I had the phone for a year before it was  
open to developers, which gave me plenty of time to understand how I  
interact with the device. I recommend you think about how you actually  
want to use the G1 on APRS, then decide what the right approach is to  
get those features.

Here is my current reasoning on the iPhone as a guide.

First and foremost, I want to get the current position from the phone  
and send it to the APRS IS and therefore to findU. On the iPhone that  
turns out to be a very easy task, it took me a couple hours starting  
from zero knowledge of the iPhone SDK (thanks to sample code!). Google  
has a pretty smart bunch of engineers, I bet it is just as easy to do  
on the G1. And, since whoever writes the program won't have to fight  
Apple censors, it will be available to every G1 user much faster.

Getting position from the phone and sending it to the APRS IS has to  
be done as a custom app, but it is pretty simple. What else do you  
want to do from your phone?

For me, next on the list was seeing the weather radar. If you have  
never been traveling and had the luxury of seeing the weather radar  
image with your exact position overlain, trust me, you want it. xastir  
can certainly do that. On the other hand, if your position has been  
sent to the APRS IS, findU can do that with a fixed URL bookmark.  
(Maybe other internet sites can as well, but I have no knowledge,  
please don't consider the lack of mention a sleight.) I keep an icon  
for the radar image centered on k4hg-8 on my iPhone, one click brings  
it up. As long as I've run the app to upload my position, that icon  
gets me the radar image I want, and in less than two seconds. Not many  
APRS clients can get a radar image from a cold start in that length of  
time, even on a high powered desktop computer and cable modem!

I also want to occasionally check to see what is around me on APRS.  
Guess what, findU (and In this case I know other sites like APRSwor;d,  
aprs.fi. openAPRS, etc. also) can do that wonderfully. I'd like to  
send messages to people. Oh, yea, findU and openAPRS can too. Get the  
idea? For a lot of the stuff I want to do on APRS, the web is already  
capable of doing it, and it even is the better choice. And at least  
for me, adding features to findU will be a lot less work than porting  
xastir.

The pages I announced yesterday are optimized for the iPhone, but it  
did not take any top secret programming knowledge to create them.  
Anyone with a G1 could produce the same thing optimized for the G1  
easily.

xastir could certainly be ported to the iPhone. There would have to be  
limitations though. For example, grabbing the APRS IS stream and  
parsing it would take a lot of battery life, is it worth it? Remember,  
when the app is running it is draining your battery, when it is not  
running you are missing data. The web servers never sleep!

RAM is limited in a mobile device, you may not be able to cache all  
the data you would like. And, the one real reason I could see to port  
xastir, connection to a TNC/radio so it could transmit on ham freqs,  
is not possible on the iPhone, and I'd bet not on the G1 either.  
RS-232 is so twentieth century!

So, right tool for the right job. Where I sit (with iPhone in hand),  
that means a custom app to upload positions, and the web for  
everything else. I urge you to think about alternatives to running a  
typical APRS client on your new  devices.


Steve K4HG




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