[OZAPRS] FW: Was Something is wrong, this is a fixed location....Now, we fixed it..

Ray Wells vk2tv at exemail.com.au
Thu Mar 10 09:41:43 EST 2011


Slightly OT but the KISS implementation in a standard TNC2 EPROM is pure 
garbage. The MFJ1270B(T) is just one such TNC to use that EPROM. It 
exhibits the most unbelievable timing and other errors such as not 
transmitting data sent to the TNC, transmitting data sent to the TNC 
after an unpredictable time delay, transmitting data over other stations 
and not passing data from the TNC to the computer. Yep, a disaster! 
However, a KISS only EPROM in the same TNC will give faultless operation.

Ray vk2tv

On 09/03/11 21:57, Gordon Taylor wrote:
> Geoff,
> 	No its an MFJ 1270B in normal TNC2 mode.  While running in KISS mode this TNC did seem to lock up after a while.
>
> I am thinking if this occurs again I will cycle power on the TNC to see if that sorts the issue.
>
> Regards,
> Gordo VK4VP
>
>
> -----Original Message-----
> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of Geoff Gatward
> Sent: Wednesday, 9 March 2011 20:54
> To: Australian APRS Users
> Subject: Re: [OZAPRS] FW: Was Something is wrong, this is a fixed location....Now, we fixed it..
>
> You're not running a KPC3+ as the IGate TNC are you??   there is a well
> known issue with these things in KISS mode introducing several minutes
> worth of delay into packet processing - they are not recommended for use
> on APRS for this reason.....
> (Currently the topic of an on-going thread on the APRS-SIG list)
>
> Regards,
> Geoff
>
> On Wed, 2011-03-09 at 20:33 +1000, Gordon Taylor wrote:
>> The issue of duplicate packets and speeds in excess of 500kmh have
>> been fixed in my area.
>>
>>
>>
>> Some troubleshooting by Dave VK4UN has shown that whenever my Igate
>> was running the duplicate packets and excessive speed changes occur.
>> With my Igate disconnected from the internet we confirmed all was good
>> as I drove from Brisbane to Buderim this afternoon.
>>
>>
>>
>> We employed that well known and often used Windows troubleshooting
>> technique of rebooting the Igate.  This has fixed the problem.  Below
>> are two packets that demonstrate the issue I had.
>>
>>
>>
>> It is clear that the packet through VK4OG-1 was gated  nearly 6
>> minutes before the packet through VK4VP-1.
>>
>>
>>
>> I assume the time stamp is added when the packet is received not when
>> it is transmitted, which in the telemetry and SCADA world I work in,
>> is just not on.  Our systems always time stamps event as they occur so
>> that any delays in the comms network do not compromise the credibility
>> of the data, as has happened here.  I am not complaining just
>> highlighting that this is an issue.
>>
>>
>>
>>
>>
>>
>>
>> 2011-03-09 03:49:40 UTC:
>> VK4VP-7>R7R4X6,VK4RBR-3*,WIDE2-2,qAS,VK4OG-1:`Q]/ }WK\]"3t}=
>>     type: location
>>     srccallsign: VK4VP-7
>>     dstcallsign: R7R4X6
>>     latitude: -27.41433333333333 °
>>     longitude: 153.0865 °
>>     course: 359 °
>>     speed: 90.74799999999999 km/h
>>     altitude: 2 m
>>     symboltable: \
>>     symbolcode: K
>>     mbits: 101
>>     posresolution: 18.52 m
>>     posambiguity: 0
>>     comment: ]=
>>
>>
>>
>>
>>
>> 2011-03-09 03:55:01 UTC:
>> VK4VP-7>R7R4X6,VK4RRC-13*,WIDE2-2,qAS,VK4VP-1:`Q]/ }WK\]"3t}=
>> [Duplicate position packet]
>>     type: location
>>     srccallsign: VK4VP-7
>>     dstcallsign: R7R4X6
>>     latitude: -27.41433333333333 °
>>     longitude: 153.0865 °
>>     course: 359 °
>>     speed: 90.74799999999999 km/h
>>     altitude: 2 m
>>     symboltable: \
>>     symbolcode: K
>>     mbits: 101
>>     posresolution: 18.52 m
>>     posambiguity: 0
>>     comment: ]=
>>
>>
>>
>>
>>
>> Regards,
>> Gordo VK4VP
>>
>>
>>
>>
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