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ZL APRS Forum NZART Conference
Held
Attended by
around 55 operators, facilitated by Alan ZL1AMW
1 Beacon intervals recommendations for ZL
operators
This topic
occupied much of the overall time, with some spirited discussions. It was recognised there is a trade-off
between sending beacons at a faster rate to give useful indication of location
when travelling, and keeping beacon rate slow to allow for more stations to
share the same frequency.
Some users
wanted a fast rate to ensure their track is well plotted, or the ensure person
they are viewing is closely tracked.
Others were much more concerned over the eventual overload of the radio
frequencies allocated. Some were
mistaking poor radio performance (which caused beacons to be dropped) with slow
beacon rates.
There was
wide agreement for fixed station beacon rates as follows:
For mobile
stations, it was stated a dumb (ie fixed timed
interval beacon) tracker should optimally send every 50 secs
for good tracking.
For smart
trackers, it is desirable to set up the parameters so that the maximum rate
would not seriously impact on the channel traffic. The min turn time setting of the Tiny Track
has a major impact on this, and 30 seconds is recommended as the smallest
number suitable for most circumstances.
2 IGATES desirable undesirable? Restrictions on power?
There was
some discussion over encouraging IGATE stations to feed international traffic
onto the radio channels. There was total
agreement at the meeting that IGATEs should limit
traffic to New Zealand beacons only, although it was noted that other views had
been expressed recently on the ZL APRS email group.
The meeting
felt that stations wanting to view or interact with overseas stations can
easily connect to an APRS server themselves, and view through their internet
connection.
It was noted
that the ZL port on the VK APRS server (aprs.net.au:10154)
used by many IGATES includes traffic from all stations with ZL Callings, plus
all stations operating within New Zealand, plus any station actively messaging
with a ZL station.
There was
no view expressed on a previous suggestion to reduce the transmit power of
IGATE stations.
The lack of
a continuous IGATE in Christchurch at that time was raised, but passed back to
Canterbury users to resolve.
3 Digipeaters
locations?, frequencies?
Three APRS
special hill-top digipeaters were noted:
In addition
there were a number of nodes and home stations acting as nodes and digipeaters mentioned.
4 Data repeaters (duplex)?
Duplex data
repeaters carrying APRS (with other packet traffic) noted were:
5 Linking between areas Desirable? How (what technologies)? Frequencies?
This was discussed
very briefly, and a preference for using RF for linking where possible was
expressed, and using internet linking where radio channels do not exist.
It was
noted the use of simplex digipeaters would impact
seriously on the maximum traffic, as all beacons are then repeated on the same
radio frequency, reducing the maximum through-put by 50%
6 Xrouter settings
enable APRS responses?
Brief
discussion indicated confusion on whether Xrouter
stations can reply to individual APRS queries.
This needs further research and clarification.
7 HF APRS Bands? Frequencies? Operating
patterns (mobile, home station etc)?
There were
some different views expressed on which is the best band, 30 metres or 40
metres.
It was
agreed that this did not really matter, all that is needed is for someone to
hear the HF tracker beacon, and if there are stations on both bands, then one
will probably pick up the signals.
The ability
for signals to be picked up by VK stations, and gated into the ZL APRS network
via internet then VHF means it is unimportant whether the signals are heard on
HF in New Zealand or not.
Time then
ran out, and there was not opportunity to talk over hardware or software usage.
Notes by Alan ZL1AMW
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