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I see what you are saying.... all signals are repeated from the
location of the external antenna... but there will be timing
differences between two people at different locations inside the
building since they are different distances from the indoor GPS
antenna.... but since this antenna is the only emitter of all GPS
signals there would be no difference in time delay from one GPS signal
to the next, so although two different users may be two different
distances from the repeater, it would really be no different than two
GPS users using two different lengths of coax on thier antennas. So
the more I think about it, the more I think you are right, everyone
would just read the location of the external antenna.<br>
<br>
Well, at least we'd know what hall they were in, and viciinity tracking
would work just as well for that... except on the kenwood radios.<br>
<br>
Back to the drawing board. That was my _one_ idea for the day, and I
blew it! ;-)<br>
<br>
Wes<br>
<br>
Robert Bruninga wrote:
<blockquote cite="mids291b373.059@FSGWHUB.usna.edu" type="cite">
<pre wrap="">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
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<pre wrap="">Wes Johnston <a class="moz-txt-link-rfc2396E" href="mailto:aprs@kd4rdb.com"><aprs@kd4rdb.com></a> 5/23/2005 10:21:14 AM >>>
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<pre wrap=""><!---->No..... it's like a passive repeater. You take an active (ie
preamp'ed)
antenna on the roof and plug a passive antenna into it. Bias the
whole
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
to
be really really deaf.
Wes
Robert Bruninga wrote:
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<pre wrap="">Also, has anyone in dayton ever considered a
GPS repeater in each hall?
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<pre wrap="">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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