[aprssig] EMERGENCY test...

andrewemt andrewemt at hotmail.com
Fri Aug 8 11:25:17 CDT 2014


Hmm... like maybe someone has too short of a TxDelay setting, such that his oscillators are still slewing when he (or a digi) is transmitting?


Sent from my Verizon Wireless 4G LTE smartphone


-------- Original message --------
From: "Lynn W. Deffenbaugh (Mr)" <ldeffenb at homeside.to>
Date:08/08/2014  12:07  (GMT-05:00)
To: TAPR APRS Mailing List <aprssig at tapr.org>
Cc:
Subject: Re: [aprssig] EMERGENCY test...

It's only a single-bit hit between his normal mbits: 010 and mbits: 000
for Emergency.

I also looked at the lat/lons and given the number of warnings coming
out of aprs.fi, I decided that it was a wasted effort.

Since the ToCall is the first thing transmitted, it even may be that he
doesn't have a long enough preamble to satisfy something along the RF
chain resulting in some garbling of the early bits of the transmission.

Only ears on the air in his vicinity will truly answer our curiosities.

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


On 8/8/2014 11:51 AM, andrewemt wrote:
> It is interesting that VE7HMW-9's packet tocall (destination) callsign
> starts with all digits instead of letters, indicating the Mic-E status
> bits are all zero. So, either someone is "fixing" his tocall (maybe
> because it doesn't look like a valid callsign, though this is worse),
> or he actually is sending emergency.  His latitude does look a little
> south for a Canadian,  but not unreasonably so for a mobile,
> considering where his home fixed station is. You'd think that if those
> three bits got mangled then more would have been mangled to give him a
> totally ludicrous position instead of one relatively close to home.
>
> Just my $.02.
>
> Andrew, KA2DDO
>
>
>
>
> Sent from my Verizon Wireless 4G LTE smartphone
>
>
> -------- Original message --------
> From: "Lynn W. Deffenbaugh (Mr)" <ldeffenb at homeside.to>
> Date:08/08/2014 10:51 (GMT-05:00)
> To: TAPR APRS Mailing List <aprssig at tapr.org>
> Cc:
> Subject: Re: [aprssig] EMERGENCY test...
>
> VE7HMW-9's emergency beacons are showing up at aprs.fi's raw packets.
> However, they're flagged with issues, so they aren't processed into
> his database.
>
> I suspect that there's a digipeater or IGate in the area that has
> PASSALL enabled and is gating invalid packets to the APRS-IS causing
> the Mic-E bits (mbits: below) to be 000.
>
> 2014-08-07 19:36:26 EDT: *VE7HMW-9
> <http://aprs.fi/?c=raw&limit=&call=VE7HMW-9>*>461QTP,VE7DID*
> <http://aprs.fi/?c=raw&limit=&call=VE7DID>,WIDE3-3,qAR,UBC39
> <http://aprs.fi/?c=raw&limit=&call=UBC39>:`2Txm"Q>/]"3m}2004 BUICK REGAL=
> *[Rate limited (< 5 sec)]*
>    type: location
>    format: mice
>    srccallsign: VE7HMW-9
>    dstcallsign: 461QTP
>    latitude: 46.19 °
>    longitude: -122.9486666666667 °
>    course: 253 °
>    speed: 18.52 km/h
>    altitude: -5 m
>    symboltable: /
>    symbolcode: >
>    mbits: 000
>    posresolution: 18.52 m
>    posambiguity: 0
>    comment: ]2004 BUICK REGAL=
>
> 2014-08-07 19:38:26 EDT: *VE7HMW-9
> <http://aprs.fi/?c=raw&limit=&call=VE7HMW-9>*>461QTP,VE7DID*
> <http://aprs.fi/?c=raw&limit=&call=VE7DID>,WIDE3-2,qAR,VA7REF-1
> <http://aprs.fi/?c=raw&limit=&call=VA7REF-1>:`2Txm"Q>/]"3m}2004 BUICK REGAL=
> *[Location changes too fast (adaptive limit)]*
>    type: location
>    format: mice
>    srccallsign: VE7HMW-9
>    dstcallsign: 461QTP
>    latitude: 46.19 °
>    longitude: -122.9486666666667 °
>    course: 253 °
>    speed: 18.52 km/h
>    altitude: -5 m
>    symboltable: /
>    symbolcode: >
>    mbits: 000
>    posresolution: 18.52 m
>    posambiguity: 0
>    comment: ]2004 BUICK REGAL=
>
> And then there's this interestingly corrupted packet:
>
> 2014-08-07 19:38:28 EDT: *VE7HMW-9
> <http://aprs.fi/?c=raw&limit=&call=VE7HMW-9>*>4Y1PYW,WIDE1-1,qAR,VA7REF-1
> <http://aprs.fi/?c=raw&limit=&call=VA7REF-1>:EGAL= *[Unsupported
> packet format]*
>    srccallsign: VE7HMW-9
>    dstcallsign: 4Y1PYW
>
> So it appears to this outside observer that there's something going on
> between the RF environment and the APRS-IS.  But if you actually
> received the Emergency packets on your radio (and it wasn't a
> third-party packet), then it would seem to indicate a bad digipeat
> rather than a bad Igate.
>
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
>
> On 8/8/2014 10:31 AM, Keith VE7GDH wrote:
>> A few times over the last week or so, a few emergency beacons have
>> been received from a VE7HMW-9, but the operator says he didn't have
>> it set to emergency. The emergency beacon was decoded by an FTM-400D
>> and also showed at findu.com, but not on aprs.fi.
>>
>> For a test, I will be sending several emergency beacons from VE7GDH-9
>> in a few minutes with a status text of...
>>
>> "This is a test - NOT an emergency."
>>
>
>
>
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> http://www.tapr.org/mailman/listinfo/aprssig

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