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[aprssig] Extending javAPRSSrvr's dupeTime

Pierre Thibaudeau ve2prt at sympatico.ca
Tue Sep 23 01:36:53 UTC 2008


Today, 17:26 -0700, Keith VE7GDH wrote:

>    Pierre VE2PRT wrote...
>    
>    > The target I was following was a balloon and it appeared to be
>    > bouncing up and down. (See the altitude value.)
>    
>    My question would be why on earth was the balloon using a path of
>    WIDE1-1,WIDE2-2? That's a three hop path that would have triggered every
>    WIDEn-N digi including the "WIDE1-1 only" digis out to the horizon.
>    Their path is part of the problem. If digis are causing the delays, much
>    of the problem can be eliminated by not going through so many digis. The
>    more digis it goes through, the more chance of it going through one that
>    can cause a delay. However, from an altitude of less than 3000 feet at
>    least in the samples you provided, maybe the impact wouldn't be huge.

Thank you for your observations. I will follow up locally.

However, these balloons climb to 75000+ft so they are heard by quite a 
number of digi's anyway. Even if they are not digipeated on RF, they 
are going to be sent over the Internet many times.

>    
>    # 1221916877  sam sep 20 09:21:17 EDT 2008
>    VE2WMG-10>APOT03,VE2RAW-3,WIDE1*,WIDE2-2,qAR,VE2PCQ-3
>    :/201321z4519.15N/07322.31WO006/020/A=000949
>    10.1V 19C HDOP01.1 SATS07
>    
>    # 1221916921  sam sep 20 09:22:01 EDT 2008
>    VE2WMG-10>APOT03,VE2RAW-3,WIDE1*,WIDE2-2,qAo,VE2HOM
>    :/201321z4519.33N/07322.16WO060/017/A=001382
>    10.1V 19C HDOP01.0 SATS08
>    
>    Both of the above went through VE2RAW-3. Therefore, VE2PCQ-3 and VE2HOM
>    should have heard the beacon at exactly the same time. It appears there
>    was a delay of abut 44 seconds.
>    
>    # 1221916927  sam sep 20 09:22:07 EDT 2008
>    VE2WMG-10>APOT03,VE2RAW-3,WIDE1*,WIDE2-2,qAo,VE2FET-1
>    :/201321z4519.15N/07322.31WO006/020/A=000949 10.1V 19C HDOP01.1 SATS07
>    
>    Above, it was gated again another 6 seconds after VE2HOM gated it.
>    VE2FET-1 should have heard it via VE2RAW-3 at exactly the same time as
>    VE2CPA-3 and VE2HOM.

Packets #1 and #2 above are different (see the coordinates and altitude). 
The target has traveled horizontally and climbed some 433ft.
Packet #3 is a repetition of packet #1, received 50 seconds after the 
original #1.

Overall, if we take out all packets that have transited through VE2FET-1, 
all is fine.

'73 - Pierre
__

Pierre Thibaudeau
VA2RKA/VE2RIO/VE2RVR/VE2RQF/VE2RTO/VE2LKL sysadmin




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