[aprssig] -IS to RF Igating (was: APRS on Android)
Eric Lorenz K9LGE
k9lge at emlorenz.com
Mon Jan 24 18:23:16 EST 2011
Dear Steve:
I am sorry that I stressed you out so...it seems to have worked fine for
me when I used it, and no one had any complaints about the amount good
or bad of characters I might have been injecting into the APRS channel.
Maybe you missed that last sentence of mine...IT"S WHAT I HAVE RIGHT
NOW. I have other things to spend the $33 on.
Again, sorry I haven't been doing it 'correctly'.
Eric
On 01/24/2011 04:29 PM, Stephen H. Smith wrote:
> On 1/24/2011 2:07 PM, Eric Lorenz K9LGE wrote:
>> Hi Lynn:
>>
>> I run under K9LGE-10 on my Droid X.
>>
>> The only other drawback is since data and phone cannnot run at the
>> same time, I have to re-enable APRSDroid after I get a call (unless I
>> have something set incorrectly and it is supposed to do it
>> automatically). So, when I am on the phone a lot in the car, I won't
>> run it.
>>
>> (The other was a failed experiment to setup a local fill-in
>> digi...discovered there *was* another digi in the area so mine didn't
>> seem to be needed).
>>
>> A little background...I travel over a lot of the midwest, primarily
>> between IL and WI and MN. I have been told that because of the amount
>> of APRS traffic on the network in WI, I probably would have next to
>> no luck in asking ops to reverse Igate...so I guess I will have to
>> save my nickels for a APRS channel.better radio-based APRS-solution.
>> My current setup uses a Kenwood TM-251A fed from a Garmin eTrex via a
>> KPC-3.
>
> Arrrgh!!! You are transmitting raw NMEA strings with this setup --
> a horrible waste of air time in urban areas. Raw NMEA sentences are
> 3 times longer than standard APRS-format strings and TEN times longer
> than compressed Mic-E format posits. [The KPC3 in tracker mode
> transmits the 100+ character NMEA string received from the GPS as-is
> without reformatting it.]
>
> Not only are you needlessly taking up more air time than required; you
> are shooting yourself in the foot by absolutely minimizing the chance
> you will be heard! Bear in mind that ALL of a packet must be heard
> PERFECTLY before ANYTHING can be recovered from it.
> The long raw NMEA packets have a far far higher chance of being
> stepped on by another station transmitting at the same time, or
> getting corrupted by mobile flutter or a pop of noise. Consider
> substituting a $33 TinyTrak III (which can generate short-form APRS
> posits or Mic-E format), and then use the KPC3 as a send/receive TNC
> under software control at home.
>
> TTIII Info: <http://www.byonics.com/tinytrak/>
>
--
Eric Lorenz K9LGE
Communications Trailer Coordinator
Disaster Services Technology
American Red Cross of Greater Chicago
630-430-2421 cell
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