[OZAPRS] Are 4 x iGates in Sydney too many?

Justin Albury justin at jacomms.com
Sun May 25 21:44:26 EST 2014

We are a bloody hard bunch to keep happy ;-)

So we all love to be able to log onto aprs.fi and see our gated beacons and track others like we do, but then when we hit a black spot with no digi or igate we are all thinking of ways to rectify this.
Goulburn and Highrange were both "black spots" along the highway until I install the digi's and a igate in Goulburn and everyone was happy, messaging works, weather warnings.... the whole bit.  A few dup packet here and there is the least of or issues...... I log every single packet gated daily, the log looks long but the file size is small and is @ 1200 baud ......Im sure a few extra igates and some dup packets is not going to make the aprsis server melt to the ground ......maybe im wrong i dunno.  What is good is to see the system getting use.....we would all hate to see it fade away like packet did....that would be sad.

Do we have a AU config standard???  do all the digi's and igates need to be updated???  this is prob a good question.

love our hobby....dont shoot it down......but lets make it work the best we can with each others help!



Justin Albury
J Albury Communications
justin at jacomms.com

-----Original Message-----
From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of vk2ycj at bravo.net.au
Sent: Sunday, 25 May 2014 8:19 PM
To: Australian APRS Users
Subject: Re: [OZAPRS] Are 4 x iGates in Sydney too many?

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.
>>>>>> -----------------------------------------------------------------
>>>>>> -------
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>>>>>>       OZAPRS at aprs.net.au
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>>>>>> --
>>>>>> Sent from Kaiten Mail. Please excuse my brevity.
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