[Vk1tac] RE: Ginini 2 metre services

Neil Pickford vk1tac@happy.emu.id.au
Sat, 18 Jan 2003 00:20:23 +1000


-------- Original Message --------
Subject: Fw: Ginini 2 metre services
Date: Fri, 17 Jan 2003 14:47:50 +1100
From: "Mr Gilbert Hughes" <ghughes3@bigpond.com>
To: "Richard Elliott" <richard.elliott@dfat.gov.au>,"Paul Elliot"
<pkbelliot@bigpond.com>, "Paul Bell" <paul.bell@afp.gov.au>,"Neil
Pickford" <neilp@goldweb.com.au>,"Keith Malcolm"
<kmalcolm@tpg.com.au>,"John Woolner" <johnwoolner@auslig.gov.au>,"Mike
Dower" <vk1eng@tpg.com.au>

Next in line on this subject!

Regards
Gilbert Hughes
mailto:ghughes3@bigpond.com

----- Original Message -----
From: "Peter Westerhof" <Peter.Westerhof@aspect.com.au>
To: "'Mr Gilbert Hughes'" <ghughes3@bigpond.com>
Sent: Tuesday, 14 January 2003 9:41 AM
Subject: RE: Ginini 2 metre services


> G'day Gil,
>
>  well what can I say, he may be right in theory, but in paractise it
all
> works fine, 10 mobiles and ten stations locally with the addition of
gated
> traffic have no adverse effect on our current setup...  As I said
before we
> have trialed a  WIDE on Ginnini and had alot of success..  Our plan
would be
> to revert VK1RBM-1 to a RELAY only digi and make Ginnini the full
WIDE.  I
> don't wnat to start a debate or argument about another WIDE etc but I
think
> that since packet activity is just about dead in the ACT let's use the
good
> old Aussie attitude and GIVE IT A GO (if only as a trial)....
>
>
> hope it helps.... APRS is becoming more popular, since beginning we
have
> gone from 1 to 18 plus 8 mobiles(some of wich are our older members.
>
>
> Enough from me.....
>
> Cheers
>
> Peter
> VK1NPW
>
> -----Original Message-----
> From: Mr Gilbert Hughes [mailto:ghughes3@bigpond.com]
> Sent: Monday, 13 January 2003 6:32 PM
> To: Peter Westerhof
> Subject: Fw: Ginini 2 metre services
>
>
> Hi Peter
>
> Got your e mail and message.
>
> Please see Owen's comments below. In summary I believe you say a wide
at
> Ginini would work provided there were fewer other wides within range,
> plus packet messages can also be supported by this system.
>
> Owen says it wont work.
>
> Feel free to talk to Owen and hopefully get an agreed position that I
> can take to the Committee and members for a decision!
>
>
> Regards
> Gilbert Hughes
> mailto:ghughes3@bigpond.com
>
> ----- Original Message -----
> From: "Owen Duffy" <owen@oda.com.au>
> To: "Mr Gilbert Hughes" <ghughes3@bigpond.com>
> Cc: <paul.bell@afp.gov.au>
> Sent: Monday, 13 January 2003 11:30 AM
> Subject: RE: Ginini 2 metre services
>
>
> > Gil, some thoughts below instream:
> >
> > >===== Original Message From "Mr Gilbert Hughes"
> <ghughes3@bigpond.com> =====
> > >(Could one of you please forward this to Karl Makin - I do not have
> his
> > >address)
> > >
> > >Following the installation of the new tower there is a much greater
> > >isolation (about 70 dB compared to 30 odd dB on the old tower)
> between
> > >the new Tx and Rx antennas.
> > >
> > >In order to save floor space (and cavity resonators) we can re-work
> the
> > >2 metre multi-coupling (currently 14 cavities) to make it easier to
> fit
> > >the Ginini 70 cm hub of the linked repeater project, and the 6
metre
> > >repeater diplexer (modified 70 MHz cavities) and the 2 mtr and 70
cm
> Rx
> > >voting equipment.
> > >
> > >This has causes us to think about what 2 mtr services we really
want
> to
> > >have on the site.
> > >
> > >Some thoughts are:
> > >
> > >1. Only two 2mtr services can easily be engineered eg voice and
> packet.
> > >
> > >2.  Does the current usage of the 4800 baud packet justify
continuing
> > >the service - (or move it to Bulls head??)
> > >
> > >3. An APRS wide has been suggested, however we understand that a
wide
> > >coverage store and forward service could do more harm than good if
> APRS
> > >continues to gain in popularity and more 'wides' are installed.
> > >
> > >4. Is there any advantage to packet users of making the site a 1200
> baud
> > >hub? (we understand that the answer is no for a number of reasons.)
> > >
> > >Does the 2 mtr packet currently  get much use now?
> > >
> > >Is the usage likely to decline even further?
> > >
> >
> > I ran up a packet station a couple of years ago, and was interested
in
> > determining why throughput was so bad on the 2m 1200Baud and 4800
Baud
> > channels, and exploring ways to improve the situation. The following
> comments
> > on packet relate to observations at that time.
> >
> > The 4800Baud channel was quite congested, which was the prime reason
> for poor
> > throughput. The mode of operation of the repeater may have
exacerbated
> that.
> > In a scenario where most stations using the repeater could not hear
> each
> > other, there is a high probability of collisions which wastes
> bandwidth. This
> > problem becomes worse at high utilisation levels where collisions
> result in a
> > snowball effect.
> >
> > It is interesting to drill down on what constitutes the traffic. My
> > observations were that it is mainly machines talking to machines in
a
> batch
> > oriented mode (eg node list transfers, network management, large
file
> > transfers often of material that is shareware and one might argue is
> has a
> > pecuniary aspect and should not be transmitted by amateur networks).
> The
> > traffic has grown to a point where the congestion renders the medium
> generally
> > unsuited to intereactive traffic, and even email (where in my
> experience, it
> > would take 1 to 3 days to get a message to a mailbox in the
> Netherlands).
> >
> > Interestingly, the example I quote above was one where I was
> collaborating
> > with a person in the Netherlands re changes to fix bugs in some
packet
> > software... but the packet network could not provide a reasonable
> > communications service to support its own development - we had to
move
> to
> > Internet email.
> >
> > My recollection is that Dave Thomson, in one of his fits of
> frustration with
> > batch transfers spoiling their digi, tore it down.
> >
> > I formed the view that packet activity was mostly about establishing
> networks
> > without any clear objectives of what service the network could
> provide, and
> > that network overheads and mindless use rendered the networks
unusable
> for
> > interactive traffic and email. Further, there is considerable
> resistance to
> > change or experimentation.
> >
> > BTW, the 70cm digi at Ginini was almost unused. The best performing
> (most
> > consistent and highest througput) path from my QTH to VK1BBS was up
to
> Ginini
> > on 70cm, across to the 4800 node, and down to VK1BBS. Even when the
2m
> 4800
> > channel was very busy and gave hopelessly low thoughput to stations
on
> 2m, it
> > was possible to get 'priority' access to the 2m node via the 70cm
> node.
> >
> > It seems to me that in 15 years, there has been little progress in
> packet in
> > this country.
> >
> > APRS, although using packet protocols (AX.25), albeit in a limited
> way, is
> > more about transmitting packets (in a broadcast mode) without
> apparently much
> > regard to whether they are received anywhere of use. My experience
is
> that
> > success rates are low, caused again in part by congestion, and
> incorrectly
> > aligned transmitters.
> >
> > My though is that wanting to increase the number of WIDE nodes that
> are heard
> > in a community increases congestion. So whilst simple thinking is
that
> lots of
> > WIDES and RELAYS increase the change of a position report being
heard
> > somewhere usefull, increased traffic causes congestion and decreases
> the
> > probability that a position report is not clobbered by another
> (hidden)
> > station.
> >
> > My suggestion is that before committing resources to a network of
> digis in an
> > adhoc fashion, that some service levels be considered, the traffic
> modelled,
> > and that the models be validated with some controlled field trials.
> >
> > Back to Ginini, the 2m voice repeater seems to get less use as time
> passes. I
> > suspect that is part of the changing amateur community that we don't
> > understand very well. Indeed, I see signs that the linked repeaters
> seem to
> > get less use the more widespread the linking - perhaps users
preferred
> the
> > 'local' context.
> >
> > If the moves that I understand are under way to downgrade the
> qualification
> > requirements for amateur radio (step 1: foundation licence, step 2:
> coerce the
> > multiple classes of licence to a single class based on the
foundation
> licence)
> > to bolster numbers of licencees (and hopefully active operators),
> there may be
> > considerable growth in demand on the facilities like 2m repeaters
that
> offer
> > much better service than the CB repeaters.
> >
> > >Would the regular users agree to either move the service to Bulls
> Head,
> > >or close it down?
> > >
> >
> > As noted earlier, my experience of a couple of years ago was that
> there is
> > considerable resistance to change in the packet network.
> >
> > Note that a number of modern transceivers come with 1200 and 9600
> packet
> > modems built in. When I looked around a couple of years ago, the
> original HAPN
> > (4800) modems had been discontinued by the Vancouver group. I am not
> aware of
> > any transceivers with an integrated HAPN (4800) modem. I suspect
that
> it may
> > be easier to get on 9600 packet than 4800, but the shared
> infrastructure is
> > supports 4800. The ready availability of both TNCs and transceivers
> with
> > integral TNC with 9600 support is a factor that perhaps ought be
> considered
> > when planning future packet resources.
> >
> > The way ahead might be to continue the 4800 service at Bulls Head,
but
> to
> > incorporate a 9600 node as well.
> >
> > It is hard pleasing all of the people all of the time Gil!
> >
> > Owen
> >
> > BTW, I have carefully avoided recommending in favour or against any
of
> the
> > services, but put on paper some thoughts on some of the factors that
> might be
> > considered in your deliberations. I hope they are of use.
> >
> >
> > >Lets have an exchange of views as a first step.
> > >
> > >Regards
> > >Gilbert Hughes
> > >mailto:ghughes3@bigpond.com
> >
> > --
> > ===================================================
> > Owen Duffy  (owen@oda.com.au)
> > Phone:  +61 2 6257 3872            (02) 6257 3872
> > Mobile: +61 417 408 424            0417 408 424
> > ===================================================
> >
> >
>
>
>
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