[aprssig] Dayton meltdown.

Robert Bruninga bruninga at usna.edu
Mon May 23 10:41:50 EDT 2005

Indoor GPS...

Yes, but everyone will still only be at the 
location of the antenna on the roof, because
that is where all the signals arrive at their
given phases.  re-transmitting them inside
the building is an equal delay to all signals,
so all positions will all still only be the position
of the antenna.  Bob, WB4APR

>>> Wes Johnston <aprs at kd4rdb.com> 5/23/2005 10:21:14 AM >>>
No..... it's like a passive repeater.  You take an active (ie
antenna on the roof and plug a passive antenna into it.  Bias the
thing with 5v to run the preamp on the external antenna.  The passive
antenna becomes a radiating antenna.  All the GPS signals become
"mirrored" inside the building.  The only problem I can see is getting
the coax thru the roof.  Think of it is cutting a hole in the roof so
that your portable GPS unit inside the building could see the sky.

I liked the vicinity tracking, but as far as I know, it's only use was
at dayton back in 1998 using those mfj data radios that were mod'ded
be really really deaf.


Robert Bruninga wrote:

>>Also, has anyone in dayton ever considered a 
>>GPS repeater in each hall? 
>But then everyone gets the same position, the
>position of the antenna on the roof.  
>My proposal for indoor tracking at Dayton is in 
>"vicinity tracking" where we put nearly deaf low-power 
>digis in each room.  With no change on the part of
>the trackers, once indoors, they start getting reported
>via the room digis and since we have full path
>tracing, then the individual is located in the room
>of the first digi that heard him.
>This was my plan back in 1998 or so.  Its all 
>written up in my vicinity.txt file.  These digis are
>called BOX-N digis and whever APRSdos sees
>a packet that comes in via a "box-N digi" it
>ignores the actual posit and plots it as a vicinity
>plot in the vicniity (100 feet) of the box-N digi.
>de WB4APR, Bob

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