[aprssig] Re: aprssig Reading APRS becons w/Dopplers?

Robert Bruninga bruninga at usna.edu
Thu Mar 16 08:23:06 CST 2006

My experience with Doppler DF units automatic
feed into APRS is that it is best to interrupt that
interface with a push button.

Only the human eyeball and brain has the sense
to interpret the data coming from a Doppler DF.
Those who use themm know when they are getting
good data and when they are getting perferctly
wrong data and garbage.

So after using one for a while, and having it garbage
up the entire APRS display with garbage, I finally
put a push button on the front panel so that I was
in control of when the data was GOOD and when
it was garbage.  I only pushed the  button when
I was seeing GOOD data.

This worked beautifully..  de Wb4APR, Bob

>>> "Curt, WE7U" <archer at eskimo.com> 03/15/06 3:37 PM >>>
On Wed, 15 Mar 2006, Steve Noskowicz wrote:

> I'm very familiar with the Doppler system as well as other DF
> tools as I was professionally in it some time ago (and have kept
> up on many of the new developments).

> I also have two new ideas I want to try (after all these years of
> thinking and not doing much).

> I hope to try these variations once it is finished in the next
> months and may use local APRS stations, as well as local repeaters
> and mobiles as guinea-pig stations to DF.  One of these ideas
> addresses the sensitivity issue, the other *may* provide some info
> to improve understanding fo multi-path.  A third (nobody expects
> the Spanish Inquisition) the broadband "whine/splatter" issue.

Please let us know what you find out, if you're able.  I've heard
that doppler scanning systems can lock on with as little as 250ms of
carrier.  Is that true?

We want to do RDF'ing of transmitters in the 200MHz range by using
coordinated APRS mobiles.  We'll need the RDF receiver, the scanning
system, a computer, APRS equipment (TNC/radio/gps/antenna), and
probably a separate voice frequency (another radio/antenna) to
coordinate the hunt.  We're talking porcupine-city here with at
least six antennas and three radios.

Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer 
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"

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