[aprssig] Marrying Doppler & APRS, Was: Reading APRS becons w/Dopplers?

Curt, WE7U archer at eskimo.com
Thu Mar 16 16:33:20 CST 2006

On Thu, 16 Mar 2006, Steve Noskowicz wrote:

>> We want to do RDF'ing of transmitters in the 200MHz range by using
>> coordinated APRS mobiles. ...snip...  Curt, WE7U.
> I suppose I could run a test on the main unit to see if it has
> enough BW to capture in 250ms.  In the narrow limit, I think mine
> has less than 1 Hz of BW.

I don't know what the parameters are that we need yet anyway.  I'll
have to do some investigation to see how the units are transmitting.

> the automation part is quite a
> sophisticated undertaking, so there are several intermediate
> solutions I'll be toying with.  I'm an RF Engineer and while I do
> some pretty sophisticated SW, getting this all together is quite a
> job and needs a real software-head  --  which I'm not.  Not to
> mention the Maping and getting everything to talk via APRS.

You mean like Xastir?  <http://www.xastir.org>  Does the mapping and
APRS stuff already.  That's what I'll be using for the RDF'ing at
some point.  It doesn't have any support in it for RDF units right
now, but that's easy enough to add.  I'm an engineer and a
"software-head".  Xastir is done in 'C'.

> I want to get close to VK3ZPF's Vector-Fox system of plotting all
> the fixes on a local map.
> http://www.qsl.net/vk3zpf/index.html

I'll have to take a look at that.

> With multiple APRS mobiles, Dopplers and a command center with a
> map, you can get pretty good, but the guy with the map can easily
> be replaced with a little code...Well, maybe a lot..

We're thinking we could have full mapping APRS systems in the
vehicles and/or have a stationary mapping system with the RDF units
mobile.  What you're thinking about though is doing away with the
maps and having software attempt to calculate the fox's location?

Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
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