[aprssig] IGate issue

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Tue Mar 18 04:37:34 CDT 2014


>From 
http://wiki.ham.fi/Aprs.fi_Info_pages#Stations_heard_by_X.2C_and_stations_which_heard_Y

>
>         Stations heard by X, and stations which heard Y
>
> aprs.fi collects monthly summaries of digipeater and igate statistics. 
> The info page shows both a table of digipeaters and igates which heard 
> the given station, and (if the station is a digipeater or igate) which 
> other stations where heard by that station. The most recently updated 
> entries are shown using a larger font.
>
> These statistics are usually somewhat correct, but there are several 
> caveats, and as you've probably heard -- there are lies, damn lies, 
> and statistics.
>
>   * The APRS-IS network that feeds the APRS packets from the igates to
>     aprs.fi does duplicate suppression. Only the first gated copy of a
>     packet traverses the entire network. All other duplicate copies
>     seen within 30 seconds after the first packet are dropped by
>     APRS-IS. A packet which is heard by multiple igates normally gets
>     credited only for a single igate.
>   * A lot of digipeaters do not add their own callsign in the packet's
>     path when retransmitting a packet. aprs.fi cannot possibly know
>     about those.
>   * A lot of digipeaters do callsign substitution instead of
>     insertion, replacing original path components. A packet with a
>     path of OH7RDÖ,WIDE2-1 could have been a WIDE1-1,WIDE2-1 packet in
>     the first place, and gone through OH7RDÖ and another unknown
>     digipeater.
>   * The aprs.fi "first heard" algorithm tries to go on the safe side:
>     if it's not sure, it doesn't count as directly heard. But even
>     then, some incorrect overly long paths are shown.
>   * Stations transmitting invalid or fake coordinates will skew these
>     statistics. If the transmitting station claims to be 1000 km away
>     (due to a bad GPS fix), my best guess can only be that the station
>     actually is that far away.
>   * Items and objects are not shown here, since they are usually far
>     away from the transmitter which transmitted the packets.
>

Packets have to meet a lot of criteria to be called "Heard by" at 
aprs.fi.  Most likely cause is that all of your stations are using the 
recommended path of "WIDE1-1,WIDE2-1" which aprs.fi doesn't consider to 
be a direct reception.  Change your mobile to WIDE1-1 or WIDE1-1,WIDE2-2 
and see if it then shows up in the list.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

On 3/18/2014 3:36 AM, Boardman, Bruce wrote:
>
> Andrew,
>
> I tried terminating the vehicle transmitter so only I could hear it 
> locally. The vehicle tracks OK but still no stations heard by?
>
> Regards,
>
> Bruce Boardman
> Telstra - Network & Access Technologies
>
> cid:image004.jpg at 01CC7EAD.B69AEBF0
>
> Ph (02) 8576 7011 <tt:0285767011?Dial>
> Mob 0427 755 678
> Telstra Depot
> Lot2/ 44-58 Duhig St,
>
> Harristown QLD 4350
>
> *From:*aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] *On 
> Behalf Of *Andrew Rich
> *Sent:* Tuesday, 18 March 2014 5:29 PM
> *To:* TAPR APRS Mailing List
> *Subject:* Re: [aprssig] IGate issue
>
> Could it be that Another Igate is faster than your reports. ?
>
> You should run wire shark program on your PC to see packets going to 
> the internet
>
> Andrew
>
> Sent from my iPhone
>
>
> On 18 Mar 2014, at 1:16 pm, "Boardman, Bruce" 
> <Bruce.Boardman at team.telstra.com 
> <mailto:Bruce.Boardman at team.telstra.com>> wrote:
>
>     Andrew,
>
>     When you say passcode, I did need a new registration number, and
>     from that I got a new Validation number which I have entered into
>     IU View under "APRS server setup". It is connected to the tier 2
>     server OK. Have a look at my Igate and you will see its working
>     but no liost like it used to have. Thanks.
>
>     Regards,
>
>     Bruce Boardman
>     Telstra - Network & Access Technologies
>
>     <image001.png>
>
>     Ph (02) 8576 7011 <tt:0285767011?Dial>
>     Mob 0427 755 678
>     Telstra Depot
>     Lot2/ 44-58 Duhig St,
>
>     Harristown QLD 4350
>
>
>     *From:*aprssig-bounces at tapr.org <mailto:aprssig-bounces at tapr.org>
>     [mailto:aprssig-bounces at tapr.org] *On Behalf Of *Andrew P.
>     *Sent:* Tuesday, 18 March 2014 11:51 AM
>     *To:* TAPR APRS Mailing List
>     *Subject:* Re: [aprssig] IGate issue
>
>     Did you change your passcode? You changed your callsign, so you
>     will need a new APRS-IS passcode corresponding to the new callsign.
>
>     Contact the author of the software you are using for a new
>     passcode if you don't have one already.
>
>     Andrew Pavlin, KA2DDO
>     author of YAAC
>     http://www.ka2ddo.org/ka2ddo/YAAC.html
>
>     ------------------------------------------------------------------------
>
>     From: Bruce.Boardman at team.telstra.com
>     <mailto:Bruce.Boardman at team.telstra.com>
>     To: aprssig at tapr.org <mailto:aprssig at tapr.org>
>     Date: Tue, 18 Mar 2014 12:45:46 +1100
>     Subject: [aprssig] IGate issue
>
>     Hi,
>
>     I recently changed address (to a different state in Australia) and
>     this necessitated a callsign change. My Igate is now VK4MQ-5 (used
>     to be VK2ZZM-5).
>
>     http://aprs.fi/info/a/VK4MQ-5
>
>     Since the change I am passing packets RF to internet OK, but I
>     don't have a "stations heard by" list any more. Also my graphs
>     show nothing. I tried firing up my mobile tracker on 10MHz so that
>     only my Igate could hear it, and the packets pass OK but still no
>     list. Other mobile stations are passing info to me which I can see
>     from their raw packets.
>
>     Looks like an APRS server problem to me, as I have confirmed all
>     my UI View settings?? Any advice please?
>
>     Regards,
>
>     Bruce Boardman
>
>
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>
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