[OZAPRS] Possible change of APRS Frequency for Victoria

Mon May 23 19:58:01 EST 2005

Hi Richard and others.. From a VK5 perspective I suspect we would present
a large problem for you on a regular basis going by the number of openings
to VK3 that we get to Mildura for example..

The Igate traffic here currently only propagates on 3 digis using a
specific path. The current recomended paths are WIDE2-2 at home and
Relay,WIDE2-2 for mobiles. This may present a problem.

I also note your reference to South Eastern Australia. Along these lines
thinking of SE South Australia. You may or may not be aware that they are
running a suedo APRS mixed network on 147.575 and the likelyhood of them
moving to 145.175 is low. Especially if you are going to put parts of VK3
on 145.175 .. So we wont get any coverage change or convergence in the Mt
Gambier Millicent and SE-SA areas.

As far as overlap you said

3)       Possible effective increase of RF coverage for overlapping
systems.

I cant see this working in VK5 really. There are still huge gaps in the
coverage overlaps in the area of 100-200kms. Unless more digis are
introduced along the borders we wont see any real advantages apart from
the frequency hopping issues. Trying to find digi sites with enough
altitude to make them worthwhile is a problem too along the highways out
there. Trying to justify a digi out there for the odd traveller once a
month is also hard. Its like putting VHF digis all the way across the Hay
plains. You would need your head read..

All that along with the duplication of the SE-SA system on 147.575 what do
you do ?

So that leaves VK2 and VK7 overlap areas.. But you said that this
frequency change was going to be for Southern VK3.. Where does this
overlap seriously with VK2 and VK7 on 145.175 ??

Theres currently a imaginary line drawn between 3RON and Hopetoun I think
where there is a change from 145.175 and 144.900 from memory. This is an
interesting area. I dont know if you intend changing anything around there
probably not by the sounds of it.
Your talking about Southern VK3 but I wonder what the effect will be in
Mildura ?

So by all means go for it but its going to have a certain impact as youve
noted. Frankly if VK2 or VK7 decided to change to 145.175 from another
channel I wouldnt be worried. The point being that they allready are on
there and we rarely see any traffic from them. The one path that would
worry me would be VK3 and so far we have not clashed for obvious reasons..

Tell me I am over reacting , fine.. The thing is that we see openings from
VK3RON 3WRM 3RVL often and for hours .. I suspect we inflict alot of
traffic on them. More than they inflict on us. I have not complained
because there are so few stations over there basically. The amount of VK2
traffic we see from Wagga and Canberra is not even worth talking about in
comparison..

We typically have 10-15 home stations and 2-3 mobiles in the metro area.
Not a huge concern generally. We also run the odd WICEN exercise on
145.175 and handle mass messaging traffic for a few days which tends to
really oversaturate the channel. For example the comming Rally of SA in
August.. We shut down alot of things in the network to help the message
traffic move through..

Yes its a national channel so there should be a way for us all to be on
there.

I wonder if its just a conveinient way to split the VK3 network and split
the traffic at the same time ? If your going to ever get the whole state
across to 145.175 you have to start somewhere I guess . Its hard to see
you changing it all at once..

Now everything Ive said may sound like pretty negative talk.. But I for
one am sick of being a APRS Policman at times telling people what paths
they are running and what they are doing to the network etc etc.. We still
have the odd mobile that pops up running RELAY,WIDE3-3 so that, no doubt
will thrill you to bits over there.. Killing certain paths in the digis
may be a option but when the propagation starts even that gets defeated.

Theres my 2 bobs worth from a VK5 perspective..

Tony Hunt VK5AH..  Flame on !!

PS. I gotta comment on this one Richard
>2)       A better shearing of infrastructure between areas.

Maybee if we stopped growing so much wheat in the Wimmera area we could
get more sheep on the land and have the required shearing. I am however
all for Sharing or shareing however you spell it..

----- Original Message -----
From: Richard Hoskin  <mailto:vk3jfk at amsat.org> (VK3JFK)
To: ozaprs at marconi.ics.mq.edu.au
Sent: Monday, May 23, 2005 2:42 PM
Subject: [OZAPRS] Possible change of APRS Frequency for Victoria

Hi,

The Victorian APRS group has had some new discussions on the possibility
of changing southern VK3’s APRS frequency to the national APRS frequency,.
Every one in the group has positive views on the change to the National
frequency, but as it will affect all of South Eastern Australia we would
like your input to the proposal.

Some background

144.900Mhz was selected as the APRS channel Before the WIA allocated the
national channel (145.175Mhz) as there was some existing infrastructure on
the channel that we could use.

The frequency change advantages are;

1)       When an operator is mobile between areas he does not have to
remember and figure out when to change channels,

2)       A better shearing of infrastructure between areas.

3)       Possible effective increase of RF coverage for overlapping
systems.

4)       Access to the nearest IGate may be reduced by a few hops.

The main disadvantages of being on a different channel are;

1)       An increase in interference from other states (VK2, VK7, VK5) for
our RF network when VHF DX conditions are good. (This effectively reduces
the coverage area of a digipeater and the network).

2)       An increase in interference for other states (VK2, VK7, VK5) from
our RF network when VHF DX conditions are good.

3)       The possibility operators may use ridicules paths such as
RELAY,WIDE3-3 or higher which would damage the RF network reliability. (
We only need RELAY,WIDE in VK3)

4)       Work involved in providing education to all operators on the
changes and if required build blocking digipeaters if operators used poor
pathing. (This would be required from VK2, VK3, VK5 and VK7).

The requirements to enable the change of frequency are:

1)       We can rase the money to pay for hardware (xtals etc) through
donations.

2)       All the digipeaters can be licensed for 145.175Mhz.

3)       There are no major objections in response to this email that can
not be overcome.

4)       There are enough people to assist in the work to change the
equipment at each site.

If you have any ideas suggestions or objections for this proposal we’d
like to here from you.

If you would like to provide a donation to assist in the frequency change
please email me.

Cheers,

Richard

VK3JFK

  _____

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