[aprssig] APRS RFID central approach (spec5)?
Wes Johnston, AI4PX
wes at ai4px.com
Fri Feb 19 07:49:03 CST 2010
Are you twisting the conductors as they run from the rfid reader to the
coil? What is the gauge of wire?
On Thu, Feb 18, 2010 at 17:41, Robert Bruninga <bruninga at usna.edu> wrote:
> Stop the presses!
> Now that I see how easy it is to make the RFID reader...
> I'm thinking of scrapping the specialized TAG-TRACKER hardware
> proposal and designing the system so that ANYONE can attach a
> $25 RFID reader to ANY TNC, and bingo, a HOT SPOT results...
> Here is the new thinking... Lets call it spec version 5...
> For the APRS-IS, then only ONE central site is needed to make
> the callsign association for the APRS-IS and this will get this
> system launched rapidly. But in local RF domains, a local
> verison would also be needed to put the result out on RF. But
> by making it work immediately on the APRS-IS, it lets everyone
> get going... I'm suggesting this could all be done at APRS.FI<http://aprs.fi/>
> (though I have not even mentioned it to Hessu yet, but I will
> use it as an example...)... We need three things to make any
> RFIS system work. A tag number, a callsign association, and a
> position of the reader. OK here it is:
> *** TAG NUMBER ***
> APRS.FI <http://aprs.fi/> (or other central processor) looks for packets
> of the
> Where S is STX
> Where dddddddddd are 10 hex characters representing the 5 BYTE
> tag number
> Where KK is a hex checksum
> Where CLE is CR, LF and ETX
> This allows ANYONE to plug this off-the shelf $24 RFID reader
> into ANY dedicated TNC that has been preloaded with the MYCALL
> of their SPOTID-S and the UNPROTO TOCALL of APRFID. That is the
> total hardware investment at any HotSpot. The reader, any TNC
> and a radio.
> APRS.FI <http://aprs.fi/> saves this tag number associated with that
> *** POSITION INFO:
> APRS.FI <http://aprs.fi/> looks for a standard POSITION PACKET from the
> TNC. It puts it on the map. The format of the position report
> is standard plus information on the desired latitude and
> longitude offset for the list of tag-users at that location from
> *that* TNC.
> SPOTID-S,APRFID,path:!DDMM.mmN/DDDMM.mmWA AARC club +100/-000
> Where most of it is a standard position report with...
> Ten bytes describing the location such as AARC Club, etc
> Then two signed 3 digit numbers.
> The first is the latitude increment in thousandths of a minute
> The second is the longitude offset for the callsign list origin
> *** CALLSIGN ASSOCIATION:
> APRS.FI <http://aprs.fi/> or other central processor looks for any MESSAGE
> from any station reporting its TAG NUMBER. Bingo, now we have
> everything. Tag number, callsign, and position. APRS.FI<http://aprs.fi/>puts
> them on the map using the incrementing latitude concept in the
> indicated thousandths of a minute of latitude above and below
> the SPOTID-S location +/- the longitude offset if any. The
> format of the APRS message making the callsign association is:
> Won't that do it and make it work entirely within existing APRS
> and using any old TNC. The only purchase for a HotSpot is the
> $24 RFID reader?
> Lets go!
> Bob, WB4APR
> > -----Original Message-----
> > From: aprssig-bounces at tapr.org
> > [mailto:aprssig-bounces at tapr.org] On Behalf Of Heikki
> > Sent: Thursday, October 22, 2009 11:43 AM
> > To: TAPR APRS Mailing List
> > Subject: Re: [aprssig] Tier 2 Routing Question
> > On Thu, 22 Oct 2009, Jason KG4WSV wrote:
> > > On Thu, Oct 22, 2009 at 9:06 AM, Matti Aarnio
> > <oh2mqk at sral.fi> wrote:
> > >
> > >> There was some radical APRS-IS Tier-2 netsplit at 03:00
> > UTC this morning.
> > >> About a third of global flow stopped flowing to aprs.fi.
> > >
> > > Why would aprs.fi be connected to tier 2 and not the core?
> > Why would it not be connected to a tier 2 server? The same
> stuff is
> > (usually, except this morning) available there.
> > I'm hosting a local tier 2 server in the next rack at the
> > same site with
> > aprs.fi. That's the server aprs.fi connects to. The server
> used to be
> > directly connected to the core servers, so there wasn't much
> > practical
> > difference whether aprs.fi connected to the local tier2
> > server or directly
> > to the core. It does save a little downstream bandwidth (one
> > downstream
> > full feed instead of two - not that it would matter at all
> given the
> > gigabit uplink), and a socket connection from the core
> > servers (they've
> > been on short supply at times).
> > It does automatically connect to the core directly in case the
> > server goes down. Also, in case the core would not be
> available from
> > Finland, at least the data from igates in .fi does get to
> > aprs.fi via the
> > local T2 server. :)
> > If there are any further problems with the T2 core
> > connectivity, I'll have
> > to reconsider, of course. But I think the issue will be fixed
> and the
> > lesson has been learned.
> > - Hessu
> > _______________________________________________
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God help those who do not help themselves.
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