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Introduction of new VHF Marine service (flashback)

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It may interest the younger folk and amuse the older folk that we have just passed the 45th anniversary of the introduction of Marine VHF radio in New Zealand.

The New Zealand Post Office - which is those days administered all things radio, including licences and examinations, introduced the service in April 1976.

Initially coverage was provided for Auckland and the Hauraki Gulf via Auckland Radio ZLD (with transmitters at Musick Point, Motutapu and on the Coromandel), Wellington and Mana/Cook Strait via Wellington Radio ZLW, and in Tauranga via the Tauranga Harbour Board.  Services were provided via channel 16 and 68 or 71 only.  These comprised listening (ch 16), weather forecasts on one of the working channels, and the taking of emergency and telegraph traffic.

If you were a club or organization wanting a shore station, you needed to apply to the Post Office.  There was an initial fee of $35 and a bi-monthly fee of $15.85. For boats the annual license fee was $16.

There were few VHF radios available in New Zealand at that point, though one was the ICOM M25, which was a fully functional 25 watt set.  ICOM still uses the M25 designation today - now as a 5W handheld.

Prior to this, many of us had inefficient AM/DSB transceivers, the simplest of which could only transmit on 2182 kHz but could receive on 2207 kHz (for weather).  If you sailed further afield you probably had one of the SSB sets available at the time.  These were crystal sets and so covered a selection of fixed frequencies across the available bands usually either 6 or 10 frequencies to cover the emergency and working frequencies of choice.  The most common transceivers for pleasure boats were built in Australia or New Zealand and had between 30 watts and 150 watts PEP depending on your needs and how much money you had to spend.

Of course the coverage and nature of VHF services expanded rapidly, as did the choice of radios.

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2 hours ago, harrytom said:

The reason they gave at the time was to much traffic for DSB. But you could transmit from virtually anywhere.

it was a bandwidth issue, DSB as it name suggests is Double Side Band/Amplitude Modulation, whilst Single Side band speaks for itself, uses half the bandwidth. Marine SSB is upper sideband whilst amateur (HAM) is lower side band

The change was an agreement by all signatories to ITU to introduce VHF and SSB world wide. NZ was a late adopter.

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9 hours ago, marinheiro said:

it was a bandwidth issue

Bandwidth was in part what I meant when I mentioned inefficiency.  The other aspect was the antenna required for efficient transmission; typically a backstay antenna with insulators.  The short whip antenna for the VHF 2m band was/is simpler and an easy option for powerboats and launches.  On my last boat in N.Z. I didn't bother with a masthead VHF antenna, and just used a whip antenna at the stern mounted a little over 2 meters high.  That was enough to give full coverage across my cruising range between the BoI and Mercury Bay thanks to the repeaters on high points of land. 

HAM operators (I am one) use both LSB and USB; typically LSB at 7 MHz and below and USB above that.  So the common HAM maritime net frequency of 14.3 MHz uses USB.

Interestingly, given the other thread discussing the recent rescue off Bream Bay, our VHF came in handy not long after they were introduced to N.Z.  Sailing south from the BoI we were a few miles off Bland Bay when we saw a smoke flare maybe 3-4 miles away.  We could see the smoke but not the boat.  At 5 knots under either sail or power it was going to take us well over 30 minutes to get there.  It was the only time I have ever called mayday.  A fast launch near Oakura heard the call.  We were able to give him an EP for the flare and he got to the distressed boat a few minutes before we did.  I believe that response time would have been slower if, these days, a boat had relied on a cellphone rather than the ability to put out an "all stations" call.

The "victim" was a plywood fizz-boat; one of those Frank Pelin (or similar) designs that were common as home-built boats during the 60s and 70s.  It had come off the top of a wave at speed and split the hull open.  When we got there it was totally swamped with four people in the water.


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