The marine AIS (Automatic Identification System) is an automatic tracking technology used by ships to send and receive position reports. Vessels send positions derived by GPS to inform others and optionally receive positions from other vessels for local display.
In Wellington we’ve been fortunate to have a DMR repeater on the world-wide DMR MARC network since August 23, 2011 where at 1930 the first contact was made with Bill N1EB. At that time there were about 60 repeaters in the network, today there are more than 300 machines in 22 countries.
Members of the DATV Project Team recently met with representatives of several Government agencies to
discuss the final series of adjacent-channel spectrum compatibility tests.
Following the extensive series of field tests that have been carried out, and laboratory simulations using an output filter
consisting of a 6-pole cross-coupled bandpass filter plus a 6-notch filter, we expect a successful
outcome from the tests.
We are grateful to one of our corporate sponsors for the bandpass filter, and also to our member Steve ZL2ASF,
for the notch filter.
From Sunday 29 September 2013 analogue television will be switched off in the lower North Island freeing up the 50 to 51 MHz portion of the Amateur 6m band for use, you will still need a 6 metre contract to operate in this part of the band.
The 502 to 510 MHz Digital TV Transmitter is being prepared for the final series of spectrum compatibility tests, to be witnessed by users of the adjacent spectrum.
Ever mindful of the cost of these tests to the users of the adjacent spectrum, we want to ensure the tests are successful at the first attempt. Accordingly, we have performed an extensive series of field tests and laboratory simulations to determine the performance margins of the transmitter system.
The unmodulated CW carrier on 506 MHz has been turned off, on the completion of coverage testing. Our thanks go to everyone who provided a reception report.
A prototype 2-way splitter, being one third of the 4-way drive splitter, has successfully passed all tests. A similar prototype, a 2-way combiner designed for higher power operation, is now under construction.
Transmission of the unmodulated CW carrier continues on 506 MHz, with horizontal polarisation. Reception reports are welcome.
Four power amplifier modules have been constructed and tested one-at-a-time with the digital exciter. Their gain and linearity match within half a dB. The four modules will operate in parallel to achieve the licensed power.
A 4-way drive splitter and 4-way output combiner have been designed and are under construction.