The official records in Australia are maintained by John Martin VK3KWA on behalf of the Wireless Institute of Australia (WIA).
Tables of the various records, along with rules and a claim form, are available on the WIA (Federal) web page at
http://www.wia.org.au/vhf_uhf/
Record distances are generally quoted to a precision of 100m, so station
positions need to be calculated to about 50m.
Maidenhead locators are not precise enough for this, so latitude and
longitude should be used.
1 second of latitude corresponds to 30.9m, and 1 second of longitude at
the latitude of Sydney is 25.6m.
Alternatively 0.01 minutes of latitude is 18.5m, and 0.01 minutes of longitude
at the latitude of Sydney is 15.4m.
Most stations will in practice use a GPS receiver to determine position -
referenced to GDA94 (Geodetic Datum of Australia 1994).
Over the past 30 years various geodetic datums have been used in Australian
maps, notably AGD66 and AGD84.
The applicable datum is indicated in the information section of the map.
AGD66 and AGD84 differ by a negligible amount.
AGD84 and GDA94 differ by about 5.7 seconds of latitude (176m) and 4.2
seconds of longitude (108m), a total distance of 206m on the ground. Thus if one
station uses a GPS receiver (GDA94), and the other uses a map referenced to
AGD84, the calculated distance between them may be in error by up to 206m
depending on their relative direction. This is hardly a serious error, but if
would be better if both stations agreed to use the same geodetic datum for their
position.