[OZAPRS] Are 4 x iGates in Sydney too many?
vk2ycj at bravo.net.au
vk2ycj at bravo.net.au
Sun May 25 20:19:06 EST 2014
Thanks Ray,
The capture effect of FM and the free for all that happens on a VHF
simplex channel is probably difficult to overcome.
Thanks for the description Ray.
Jamie VK2YCJ
> Guys and Gals,
>
> Take a look at recommended paths and you'll see why multiple digis are
> retransmitting a station.
>
> A mobile with WIDE1-1 WIDE2-1 will have two hops. Most, if not all,
> digis respond to WIDE1-1, so most digis will retransmit a WIDE1-1 packet
> for another hop (to any other digis that hears it) and that (those)
> digis will use the WIDE2-1 part of the path. A path of WIDE1-1 WIDE2-2
> will have three hops, extending the spread to another ring of digis and
> potentially more igates.
>
> The reason for the closest igate not always being the one that appears
> on aprs.fi (et al) is that the nearest igate might be clobbered by
> another station that is stronger than the local digi - think FM capture
> effect - OR the received packet might be mangled in some way through
> collisions, and "lost", whilst a distant igate will receive a valid
> signal via its local digi and deal with it appropriately.
>
> APRS is a bit (a lot!) of a free-for-all for channel access compared
> with connected mode packet where stations hold back transmitting, as
> defined by the channel access parameters of DWAIT, Slottime and
> Ppersistence.
>
> A situation I see reasonably often is, I can be gating a station that's
> using vk2rcn-1 just fine, sending numerous packets to aprs-is and then,
> out of the blue a packet will go via a couple more digis to be gated by
> a station in Tamworth. I'm in Kempsey. Obviously my rx has been
> clobbered by vk2rdo-3, vk2rmy-1 or vk2jub-3 and I lost the packet.
>
> Ray vk2tv
>
> On 25/05/14 17:12, vk2ycj at bravo.net.au wrote:
>> Gary,
>>
>> Interesting yes. I can see a mobile station in Newcastle going to
>> VK2RTZ-1 then to VK2RTG-5 rather than via our local iGate VK2ZEN-5
>>
>> VK2ZEN-5 looks like it's okay and working.
>>
>> Another mobile up the valley is going via VK2RTZ-1 and then to iGate
>> VK2ZEN-5
>>
>> Maybe it's a difficult job to get to site and set the routing table on
>> the
>> VK2RTZ-5 digipeater if changes are needed.
>>
>> Can the routing tables be set remotely via the 145.175 access frequency
>> OR
>> can it only be done with a PC and cable onsite ?
>>
>>
>>
>>
>> Jamie VK2YCJ
>>
>>
>>
>>> Maybe the "path police" should be looking at some of the digi's around
>>> the place.
>>>
>>> I wonder why I see traffic from sugarloaf on highrange being digi'd ? I
>>> would have thought there are closer igates that the path should be set
>>> (& honoured) that highrange wouldn't digi this stuff ? Maybe its
>>> highrange at fault ?
>>>
>>>
>>> On 25/05/14 15:20, vk2ycj at bravo.net.au wrote:
>>>> G'day,
>>>>
>>>> I am thinking about using a hand-held 2m rig like a UV-5R as a low
>>>> power
>>>> "fill in" digipeater for a small country town ?
>>>>
>>>> I drive to Dungog from Newcastle (80Km by road north of Newcastle) 4-5
>>>> days per week and the APRS coverage is poor or non-existent.
>>>>
>>>>
>>>> I was considering two options:
>>>>
>>>> 1. Putting a UV-5R hand-held radio on a hill near Dungog as a "fill
>>>> in"
>>>> digipeater running 1-2 watts and solar powered. The hill is line of
>>>> sight
>>>> to the main digipeater on the Sugarloaf Range in Newcastle.
>>>>
>>>> 2. Putting an Alinco DR-135T (with Argent Data card T2-135) running 20
>>>> watts and not solar powered. The boys at Goulburn NSW have installed
>>>> two
>>>> of these recently with good results.
>>>>
>>>>
>>>> Can someone please comment on the suitability or stupidity of the
>>>> above
>>>> two options ?
>>>>
>>>>
>>>> Thanks, Jamie VK2YCJ
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> I have been looking at the load on one server in the rotation, which
>>>>> is
>>>>> about to move hosting into one of my racks... which is why previously
>>>>> I
>>>>> said there was no issue.
>>>>>
>>>>> I do see some issues about the place, with a few WIDE3* and a few
>>>>> NOGATE. I would have thought a NOGATE should also include NO-DIGI,
>>>>> but
>>>>> its seems maybe I have the wrong assumption.
>>>>>
>>>>> Maybe we do need someone to have a look at some of the paths being
>>>>> used
>>>>> and clean them up.
>>>>>
>>>>> I would have thought its best to try and keep RF clear so more can be
>>>>> handle without drama.
>>>>>
>>>>> Gary
>>>>> vk2zbb/vk2lv
>>>>>
>>>>> On 25/05/14 11:50, Scott Evans wrote:
>>>>>> From a T2 perspective there's no issue! If you're using
>>>>>> aunz.aprs2.net
>>>>>> rotate the load balancing is automatically taken care of, however if
>>>>>> you
>>>>>> have set up a static server and if everyone else had done similar
>>>>>> then
>>>>>> maybe a problem would exist!
>>>>>>
>>>>>>
>>>>>>
>>>>>> On May 25, 2014 11:32:59 AM GMT+10:00, Liz VK2XSE
>>>>>> <edodd at billiau.net>
>>>>>> wrote:
>>>>>>
>>>>>> QTR Thu, 22 May 2014 21:47:13 +1000 Ian Mills QTC
>>>>>>
>>>>>> I've noticed we now have at least 4 x iGates in Sydney, I
>>>>>> would
>>>>>> have
>>>>>> thought that's too many and may be adding extra loads on
>>>>>> the
>>>>>> sever as
>>>>>> they all gate the same traffic?
>>>>>>
>>>>>> Ian vk2him
>>>>>>
>>>>>>
>>>>>> The guys in the US, who have more experience in handling large
>>>>>> traffic
>>>>>> volumes, seem to whinge far more about excessive digipeating
>>>>>> than
>>>>>> excessive iGating.
>>>>>> I did notice on my last trip to Wollongong that my packets
>>>>>> were
>>>>>> being
>>>>>> spread far and wide, and often gated from Newcastle after
>>>>>> being
>>>>>> picked
>>>>>> up by VK2AMW-1. (WIDE2-2)
>>>>>>
>>>>>> The questions can best be answered by experimentation.
>>>>>> There is apparently a need for better RF coverage in Sydney.
>>>>>> How
>>>>>> much
>>>>>> redundancy is required in the iGating system could be explored
>>>>>> by
>>>>>> deliberately turning off internet connectivity at one or more
>>>>>> of
>>>>>> the
>>>>>> Sydney iGates.
>>>>>> Sydney users would need to know when these changes were made,
>>>>>> and
>>>>>> then
>>>>>> comment on negative and positive aspects of the changes.
>>>>>> We would also need to know how many hops people are using in
>>>>>> their
>>>>>> transmissions.
>>>>>>
>>>>>> And is there any information from the APRS-IS server operators
>>>>>> about
>>>>>> network load?
>>>>>>
>>>>>>
>>>>>> -+-+-+-+-+-+-+-+-+-+-+
>>>>>> Liz
>>>>>> VK2XSE
>>>>>> who hopes not to be using APRS in Sinny, 15 years living there
>>>>>> was
>>>>>> enough.
>>>>>> ------------------------------------------------------------------------
>>>>>>
>>>>>> OZAPRS mailing list
>>>>>> OZAPRS at aprs.net.au
>>>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Sent from Kaiten Mail. Please excuse my brevity.
>>>>>>
>>>>>>
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