[Xastir] More system questions

[Richard Polivka, N6NKO]

In checking the station details, he/she is showing a range of 20 miles. 
Remember, that number is based on a clear shot. Burnett County is not 
that flat and is tree laden. The effective range for the station will be 
less. It appears that in a 50 mile radius of Burnett, I count four 
stations advertised as being active on APRS.

The idea of just using a transmit-only tracker was a idea to keep it 
small and lightweight. A full TNC, battery, radio, and reasonable 
antenna will be cumbersome for the person to carry. The key here is 
ANTENNA. You gain on  both ends, RX and TX. Probably the best way to do 
an antenna is to use a long rubber ducky antenna and use the metal frame 
of a backpack as the ground plane.  Plus, it is easier to carry day 
supplies and the metal frame is far easier on the back than a softshell 
pack.

If you are going to go the radio/tnc route, I would set up the units to 
also be digipeaters as well. This would give the low level signals a 
better chance to propagate. I do not know if the D7A will digi as well, 
so I would look into it.

This is not going to be cheap if you go with off-the-shelf solutions. 
Cobbling would save much but if the capability is not there, you will 
have to bite the bullet.

Good luck.

73 from 807,

Richard, N6NKO

Jim Tolbert wrote:
> Thanks Tom....  Yes... We live in the undeveloped boonies.  But then, 
> we like it that way <grin>.
>
> The one digipeater that is in out county is AAOKU-WL and 4min.  What 
> does that tell us?
>
> Thanks ........... jt
>
> Tom Russo wrote:
>> On Wed, Jun 27, 2007 at 03:37:52PM -0600, we recorded a 
>> bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
>>  
>>> You could also set up an Xastir station to listen using an APRS-IS 
>>> server
>>> (nternet only) fairly quickly, and look for the digis on your map.  To
>>> do this, you'd want to  use a filter that specified "r/45/-92/500" 
>>> or something to give a nice big range of stations near you.  I'm 
>>> actually looking at such a thing right now.  In the few seconds I've 
>>> been watching,
>>> I see that there are quite a few digipeaters, but they are all 
>>> advertising
>>> fairly short ranges (through their PHG settings, which may or may 
>>> not really
>>> indicate their effectiveness, as it's a very crude measure).
>>>
>>> I'll take a screen shot of your area viewed in xastir in an hour or 
>>> so after
>>> I've captured more data.  I'll put it on my web site and post here 
>>> with the
>>> URL.
>>>     
>>
>> I think I've got all that I can get, since I've already heard from the
>> digis that are closest to you.  I have a snapshot, it's at
>>   <http://www.swcp.com/~russo/imgs/wiscsnap.png>
>>
>> Look at the pale green circles --- they represent the digipeaters at 
>> the center
>> (where the star is) and their advertised ranges.  The southeast 
>> portion of
>> Wisconsin appears saturated with digis with overlapping ranges, but your
>> western portion is thinner.
>>
>> It looks like your county is pretty much without a local digipeater 
>> at all.
>> The nearest digis to the location you sent are advertising ranges 
>> that don't quite cover the distance between your location and 
>> theirs.  You might
>> have trouble hitting those digis during SAR missions, but you'll want 
>> to try out a tracker in your normal operation area before concluding 
>> that.
>> You could get a single D7 radio, wire it up to a GPS, and use a path 
>> like
>> WIDE2-2 to see if you get digipeated --- you could monitor the whole 
>> thing
>> on findu without having any other infrastructure to see if you're 
>> making it
>> to a digipeater and an Igate.  Not a solid test (you could be 
>> reaching a digi
>> but not an igate), but you could still tell if you're getting 
>> digipeated because
>> the D7 would report when it hears its own packets back. 
>> If your local infrastructure isn't built up enough then you might 
>> need some assistance to get a new digi installed nearer to your 
>> operations area, or
>> you could deploy a portable digipeater on missions --- yet another 
>> piece of
>> equipment to purchase and maintain, but perhaps easier than getting a 
>> full-time
>> digi set up so that it reaches where you need it.
>>
>> Curt likes the idea of using Tracker2 units to deploy a bunch of 
>> man-portable
>> digis into mission areas.  I'm still skeptical, but it could work 
>> well.  How's
>> that going, Curt? (ignoring the fact that Tracker2 is still not ready 
>> for
>> prime time, so doesn't answer Jim's needs yet)
>>
>>   
>