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[aprssig] Re: One last question on digipeater code for TNC-X

Ian ZL1VFO zl1vfo at yahoo.co.uk
Thu Aug 18 05:39:26 UTC 2005


>>
>>Would you consider implementing an individual time 'offset' much like
>>the UI-Digi firmware intended to have but didn't quite work right?
>>(Well, it didn't seem to work for me at all, really...)
>>
>>-Ian ZL1VFO
>>  
>>
> Could you comment a bit further on what this is supposed to do.  I've 
> read a couple of pieces of on line documentation, but I'm afraid I still 
> don't understand what it's getting at.

> Thanks,
> John W2FS

I get the APRS-Sig via digest mode, so my apologies in advange if
anyone has explained this before I receive the digest & find out
myself.

OK. Consider the folowing. We start with the time that power is
applied (i.e. it's switched on) to the repeater controller as 0
(zero), and for the sake of the example, it'll be midnight.

To keep the explanation simpler, I'll use only 3 beacons.

Beacon 1 has an offset of 15min, and a rate of 30 min (say a path of
ID, or nothing perhaps) It should beacon at 1/4 past, and 1/4 to every hour

Beacon 2 has an offset of 30min, and a rate of 60 min (say a path of
wide2-1) so it beacons at 0:30, 1:30, 2:30, 3:30 etc

Beacon 3 has an offset of 0min, and a rate of 120 min (say a path of
wide2-2) so it beacons at 0:00, 2:00, 4:00, 6:00 etc

so we get
12:00                      Beacon 3
12:15  Beacon 1
12:30             Beacon 2
12:45  Beacon 1
 1:00
 1:15  Beacon 1
 1:30             Beacon 2
 1:45  Beacon 1
 2:00                      Beacon 3
 2:15  Beacon 1
 2:30             Beacon 2
 2:45  Beacon 1
 3:00
 3:15  Beacon 1
 3:30             Beacon 2
 3:45  Beacon 1
 4:00                      Beacon 3
 4:15  Beacon 1
 4:30             Beacon 2
 4:45  Beacon 1
 5:00
 5:15  Beacon 1
 5:30             Beacon 2
 5:45  Beacon 1
 6:00                      Beacon 3

 ok, so the immediate area gets beacons 1 & 2 every 15 min - this is
 probably excessive to some degree, but I'm only using this as an
 example, and every so often, we miss a beacon. 1:00,3:00,5:00. (Hey
 good use for a 4th beacon, offset 1hr, interval 2 hrs...)

 With the UI-Digi, what appears to happen is that even if one sets the
 OFFSET time to some non-zero amount (big, small, whatever), the
 apparent offset it uses is zero. So in the above example, we would
 actually get this (below)
 
12:00  Beacon 1   Beacon 2  Beacon 3
12:15
12:30  Beacon 1
12:45
 1:00  Beacon 1   Beacon 2
 1:15
 1:30  Beacon 1
 1:45
 2:00  Beacon 1   Beacon 2  Beacon 3
 2:15
 2:30  Beacon 1
 2:45
 3:00  Beacon 1   Beacon 2
 3:15
 3:30  Beacon 1
 3:45
 4:00  Beacon 1   Beacon 2  Beacon 3
 4:15
 4:30  Beacon 1
 4:45
 5:00  Beacon 1   Beacon 2
 5:15
 5:30  Beacon 1
 5:45
 6:00  Beacon 1   Beacon 2  Beacon 3

 You end up with 'Clusters' of 2 or 3 beacons.. One can mitigate this
 to some degree by using numbers that aren't a multiple of others
 (Primes, perhaps), but it's a pain-in-the-backside & would be nice
 to have the Interval + Offset times work as they were intended
 (according to the configuration text,  anyway...)

 Hope that clarifies things..
 
 And on a related note, if you are open to a wish list, the ability to
 somehow connect 2 or perhaps 3 TNC-Xs up together to cross-digi would
 be a great thing.
 Think 144.39 Tx/Rx, 144.99 Rx, 70cm backbone/link Tx/Rx

73s
Ian Zl1VFO

P.S. Has the TNC-X yahoo groups reflector died of under-use...?


		
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