[aprssig] IGate issue
Lynn W. Deffenbaugh (Mr)
ldeffenb at homeside.to
Tue Mar 18 05:50:20 EDT 2014
And interestingly enough, here's a response from Hessu on his aprs.fi
Google group just this morning dealing with the same question:
> On Wed, 12 Mar 2014, Asbjørn Hauge wrote:
>
>> I've noticed a strange behaviour about heard positions-map lately. If
>> I look at station info and select "show on map" (heard directly), I
>> miss a lot of positions
>> where I've been credited for the qAR according to raw data.
>
> qAR indicates the igate (station which passed the packet to the
> APRS-IS from RF), not the station which heard the packet first /
> directly. Try the 'gated' map (Position packets sent to APRS-IS =>
> Show on map) instead to see the full service area of the igate:
>
> http://aprs.fi/#!v=gated&call=a%2FLA1HSA-1&timerange=3600&tail=3600
>
>> http://aprs.fi/#!mt=roadmap&z=11&v=heard&ym=201403&call=a%2FLA1HSA-1&timerange=3600&tail=3600
>>
>> This map does not show LD2BI even though I'm igating it on a regular
>> basis. This isn't critical for local use, although it's nice to see
>> coverage.
>
> LD2BI arrives to your igate with a WIDE2-1 path, which gives aprs.fi a
> strong hint that this packet has been digipeated by some digipeater
> first, and it's probably not "heard first" by your igate. From over
> here, behind the APRS-IS, it's really hard to tell whether LD2BI
> transmitted with a WIDE2-1 path originally, or if the packet went
> through a digipeater and WIDE2-2 got adjusted to WIDE2-1.
>
>> A more interesting situation was the balloon M0XER-8
>> (http://aprs.fi/#!mt=roadmap&z=11&call=a%2FM0XER-8&timerange=604800&tail=604800).
>> I did not get any hits for
>> this on the "heard map" for February, which is sad since I really
>> wanted to see the path when it was high up in the air.
>
> Same here, WIDE2-1 path.
>
> This is a frequently asked question, please search the discussion
> group archive for "heard", there's a lot of questions and answers on
> the topic already.
>
> - Hessu
On 3/18/2014 5:37 AM, Lynn W. Deffenbaugh (Mr) wrote:
> 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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>>
>>
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>
>
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