Hi,
can sombody indicate the range at which access is still possible tp weather transmissions on VHF out of Darwin harbour. I relise this is dependant on a few variables with my gear but have been in contact with the Harbour station from the set locally to accertain that it is working and all appears to working fine in transmision and reception strength. I am assuming that, that station at least would be operating through a coastal repeater station. My question is how far away would one expect (and others have) to be able to contact that station. I am planning a 3 night trip within the month to either south of Dundee/ Perron to Capes ford and Scott or to Minni Minni out of either the South or mabey the East and am thinking that I wouldnt mind the back up of access to the weather scheds. Or essentially would coastal shipping and barge traffic be the only VHF contact candidates that far from Darwin Harbour, in others experience. It is my to post some details of proposed trips in a few days to gauge reaction to both the practicallity of alternative plans and if others may be interested in an outing.
Wouldnt like to be to far away at the moment with this easterly bust on at the moment though.
Thanks in anticapation any help would be appreaciated.

AM

As you said, it depends on what setup you have as to how far you can pick transmissions up so I can only go by what I have had. With an Icom 403 and 6ft aerial I have picked up the channel 16 callover for weather at both Fourcroy and around Camp point and Soldier. I have also picked it up as far as just west of the Perons but not in closer to Blaze. There is nothing at the Mini and I have never received any Darwin radio broadcasts from that side at all. Now with the Raymarine unit my distance is not increased much but have picked Darwin up outside Port Hurd and as far as Cape Ford in good weather. Hope that helps, but I find the insurance of a sat phone the best option when doing any of the wide trips.

Cheers.

_________________

Hi

I planned, designed and installed the VHF repeater network in Qld and other states.

The proper talk-through-repeaters (ttr) not the remotely controlled ones mistakenly called " repeaters".

However the principle for working out the range remains the same.

Range is directly proportional to height above the water.

A VHF set on top of a 900ft hill will have a radio horizon range of 60 nautical miles.

The rule-of-calculation for VHF marine (which is simply hi-band VHF) radio horizon is :

horizon distance in nautical miles = 2 x sq root of height in feet.

eg 900 ft high = 2x 30 = 60.

Radio horizon of your boat (assuming the centre of the antenna is 9 ft above the water = 2 x 3 = 6 nautical miles.

Doesn't sound much does it?

The actual range is found by adding the horizons together.

Your boat trying to listen to a weather station on a 900 ft hill would have a workable range of approx 60 ( base horizon) + 6 (your boats horizon) = 66 nautical miles.

Your workable range to another boat similar to yours would be approx 6 (your horizon) + 6 ( the other boats horizon) = 12 nm direct boat to boat.

Your range to a yachtie whose radio antenna was on top of his 49ft mast would be 6 (your horizon) + 14 (the yachtie's horizon which is 2 x sq root of 49 or s2x 7) making 20 nautical miles.

Find out where the weather station base is and look the height up on a countour map. Do the maths and that gives the radio horizon of the base station.

A 900ft base would let it work boats from 66 nm in all directions. Bit further if the boat antennas are higher like yachties, trawlers etc.

But only the base station would have that range. Your wouldn't in your little boat.

However, if the base was turned into a proper talk-thru-repeater, your range would increase significantly. As long as you were within range of the ttr you would be able to talk to anybody else who was also within range. eg if you were 65 nm south of a ttr and another boat was 65nm north of the same ttr , you'd be able to talk boat-boat over 130 nm range!

I put 35 of these ttr repeaters into service in Qld and NSW in the mid-eighties. When I was the national communications officer for both the coast guard (AVCG) and the Air Sea Rescue oprganisation.

Despite my offer to NT organisations to install some for no cost, nobody in the NT was interested in doing anything. So I didn't bother either.

Those ttrs have saved many lives in Qld. I don't know if anybody eventually got off their backsides in the NT and did anything about installing VHF ttrs. If not they should.

Note that the distances are nautical miles not km

Radar ranges are calculated in a similar fashion using horizon additions except the multiplier is 1.2 x the sq root of the height in feet due to the higher frequencies being used.

If u know where the Darwin weather station radio base is actually located, let me know and I'll find it on a contour map and work out ranges to sea for u if u like.

regards
Ronj

Thanks very much replys! a fair bit to digest in the later one ronje. I might print that one and see if a small amount of Shiraz might aid in digestion this evening.
I can agree with the comment about the TTR in SE Qld after fishing for many years wide of the breaksea spit, without any shadow of doubt assistance is just a radio call away 24/7 not to mention the sea phone if it it still operates.

Am,

Seaphone is dead, that is how I managed to get a subsidised sat phone kindly donated by the Federal Government.

_________________

OK AM
.
The Breaksea Spit is pretty bad country. I put a repeater on Sandy Cape Lighthouse just to service the Spit area and areas wide of Fraser Island.

Hervey Bay Air Sea Rescue minitored that repeater ( Ch 83 initially from memory).

Aslo put in the one at Big Angle and Mt Wolvi at the bottom end of the island.

Also did the UHF cb repeaters on the Island and Double Island Point lighthouse.

The Seaphone people (OTC) tried to stop the repeaters going in as it it would kill the limited Seaphone servoice that OTC was trying to make money out of unsuccessfully.

There was a bit of VHF marine about the coast but the standoff was that few had VHF because OTC wouldn't provide a decent service.

OTC wouldn't expand Seaphone cause few had VHF. Catch 22.

John Dahl of Magnum Marine Electrinics in Brisbane and me in Bundaberg put in VHF marine repeaters at Mt Glorious in Brisbane and the Sloping Hummock at Bundaberg on the same day.

That broke the stalemate and the rest is history. NZ and the US picked up the repeater system principle. Seaphone and OTC eventually folded up.

regards
Ronj

Sorry Ronje, but I made the call a thousand times , VMR 466, VMR 466 Vessel JQ , JQ (Juliet Quebec in bad reception) on VHF channel 22. In those days Ken and his boys did an increadible job, as said 24/7, may the VMR network live forever. We would do the face to face thing once a year at the toyota fishing comp where they would set a complete stand alone local VHF station up with a comp frequency for a week, great days. we may ave a few mutual aquantances.

Nope

Ch 83 was the original channel.

I used 80-81-82-83 and 84 originally on all the repeaters. 84 was set aside for pro fishing to keep them off the other channels.

OTC tried to get the Dept of Communications ( the radio inspectors) to stop the spread of repeaters. I was the District Radio Inspector for Wide Bay/Burnett for the Dept of Communications at the time. I offered to stop the spread of ttrs if OTC would guarantee to fix their coverage deficiencies. They wouldn't do that but offered to put extra Seaphone services on Ch 83 and Ch 84.

It was simply a ruse to restrict the number of repeater channels which could be used.

Mt Dept said ok and allocated Ch 21 and Ch22 instead of 83 and 84 thinking they were doing the right thing by me and marine users. Their thinking was technical in that the frequencies of 21 and 22 were interleaved with 80, 81 and 82. Nice and technically neat.

OTC never put services on 83 and 84 in Qld justifying my claims of a ruse at the expense of safety of maritme users. OTC was a flawed federal government organisation hungry only for the dollar.

The Federal Govt ( under its obligations to ITU agreements) paid OTC several million dollars a year to provide radio monitoring on marine distress channels 2182, 4126 and 6214 along with Ch 16 VHF. They provided minimum service and absorbed the rest into their budget coffers. Disgraceful behaviour by a govt agency.

However, my silly work colleagues from Brisbane and Canberra ( having no experience of hands-on marine radio operations ) didn't realise that the channels were inconveniently at opposite ends of the dial! So I was stuck with 21 and 22.

I then changed some of the operating channels for those on 83 and 84 including Sandy Cape Lighthouse.

Unbeknowns to DOC and OTC I had previously used Ch 22 on Fraser Island for a temporary repeater for the Orchid Beach fishing competition and Sandy Cape ended up on 22 as a natural change. My memory the comp was organised by a couple of brothers from Brisbane who had a motor dealership ( Toyota I think).

They provided a brand new 4WD and Qld Harbours and Marine Dept Publicity Manager Wayne Box, the police radio section boss Neils Petersen of Maryborough and I drove around the top end of the island for a couple of days to find a suitable site for this temporary repeater. The thinking was that the Maryborough/Hervey Bay police and Hervey Bay ASR would only get involved if something went wrong and they wanted a relaible comms channel out there. In the meantime it could be used by the comp for coordination purposes.

We stayed with my friend Harry Tait who was the lighthouse keeper at Sandy Cape.

Instead of me having to get involved with the fishing competition each year ( I couldn't afford the time), I handed the annual project over to a work colleague of mine who loved fishing etc.

His name was Boyd Rayment from my Brisbane DOC office.

I had also previously spent another week on the island with John Fisher and Graham Lucke ( radiocommunications servicemen from Bundaberg) finding sites for UHF CB repeaters.

We put 1 repeater on Double Island Point lighthouse looking down Teewah beach and up Fraser I beach. We put another repeater at Indian Head looking down Fraser Is beach and up towards Sandy Cape.

I had friends in the Federal Dept of Transport who administered the lighthouses and was guaranteed access.

One of the more interesting ones was Cape Byron lighthouse in NSW. I put a repeater in there weeks before the "hug old buildings" Heritage brigade gained control. They had to undertake to ensure that any relocation of equipment from the lighthouse would not be disadvantaged. So they had to pay to shift it to one of the accommodation houses at their expense. I think it was the NSW version of the AVCG/ASR ( maybe Coastal Patrol or NSW SES?) who benefitted from that move.

I also had dealings with a well known boat builder from the Gold Coast who ( in conjunction with Bill Hammond of Beenleigh Marine) supplied free of charge the radio equipment for the first 10 repeater installations. They could see the advantages of what I was up to for maritime users and indirectly for their businesses.

The motivation was aimed directly at helping the rescue groups with decent comms for rescue and search coordination purposes while at the
same time encouraging boating users to go VHF.

Bill died a few years after that from Big C and John Haine died just recently.

My memory one of the groups I contacted in the NT was the St John Ambulance Brigade who were doing marine stuff under some arrangement with the NT Govt. None of the groups I contacted had any idea about VHF and ( I think) OTC at Darwin were running a bit of an interference campaign to prevent VHF marine repeaters coming. Anyway, I had enough on my plate with Qld, NSW, Tas and Vic so concentrated on them leaving NT to return to blissful slumber.

Any of those names familar to you?

regards
Ronje

Hi Ronje ,
The only one that does is Boyd whom I beleive I met at one of the earlier toyota comps on the Island he was assisting the Qld Transport set up a radio base station for that comp and we were involved with the century battery sponsership of that Depatment with Wayne Box at the time.
A lot of water under that bridge since then.

U know Wayne ended up as guest of her majesty?

The story is that as the public relations guru for the H&M Dept he was caught out taking kickbacks under sponsorship deals for various activities.

He had a bank account under a false name into which the kickbacks were paid and he appeared on TV one night. One of the bank tellers was watching tv and recognised him as the owner of an account under a different name at her bank. The rest is history!

Boyd was the obvious choice to take over from me as he was a keen fisherman and just loved the social side of competitions although he was a teetotaller!

What were u doing in the Wide Bay region? I drove the big 8.8m cat with 2 x 225 hp o/boards of Bundaberg Air Sea Rescue for 12 years. Spent some time around Breaksea Spit and surrounding waters.

regards
Ronj

Yeah Ronje Im aware of the history and know Wayne, and his wife and kids quite well seems he did the crime and the time (albeit a while ago now). Still see a bit of them actually around Anzac day usually.

At the time I was line fishing commercially for mackeral and demersal fish on a beach launched 6.7m trailer boat with my father inlaw who still lives at Orchid Beach now though retired.

Hope Wayne was able to get his life back on track.

Wouldn't be the first one who got so enmeshed in working life that eventually something had to give. Next time u see him say hello from me (the radio inspector from Bundaberg and Boyd Rayment).

Used to know most of the pro fishermen in the Wide Bay region through work . Most of them were fishing due to it being a way of life and they mostly eventually failed.

The ones who treated it as a business did OK. If they failed it was usually due to matters outside of their control like Govt changes to the industry.

Had a lot of dealings with Sid Melksham ( unofficial mayor of FI) of Eurong, the sandminers at Rainbow and eventually the anti-logging brigade on the island. Some tough times there.

Got to know Vern Lee of Tin Can Bay well. He had a trawler for each of his children. Best trawler operator was his daughter who became qualified and skippered her own boat. Tough and smart lady ( quite young). Vern used to originally run the Fish Board in Tin Can Bay and branched out.

Nigel Fremantle used to operate the taxi service and 4WD recovery service on FI. Guess lots do now.

Last time I was on Fraser Island I was helping the coppers with a problem associated with the anti-logging movement. Pretty interesting.

I ended up camping in the anti-logging camp. Most were rent-a-protest people paid an allowance of $7 per day for food by the wilderness crowd from NSW. Professional protestors. Dick Smith store provided them with comms equipment which we were able to intercept so always knew what was coming and therefore no surprises ensued.

Waddya doing now?

regards
Ronj

Couple of years ago now.

Got some info about the VHF transmitting sites for these 2 places.

Darwin installation ( called Coast Radio Darwin) is operated by harbour personnel on Darwin harbour.

The actual transmitter is on top of NT House in Mitchell St at a height above the water of approx 80 metres (262 ft).

Its transmitting range to a recreational boat ( commonly called skid boats) is approximately 38 nautical miles.

So draw a 32 nautical mile radius from NT House.

Its range to a yacht with its antenna on top of a 50ft mast would be approx 46 nautical miles.

At Gove the transmitter is on top of a 60 metre ( 196 ft) gantry gives a range to skid boats of approx 34 n miles and to a yacht with its antenna on top of a 50 ft mast would be approx 42 n miles.

So much for the hilltop sites of 900 ft or so!

Anybody know of a 300ft or better hill/ridge 50 - 70 k to the south-west of Darwin not far from the coast that's accessible?

Ronj

What about the light house at charles point...???

Thanks 2 rods.

Unfortunately I don't know where Charles Pt is.

Can u give me a lat/long so I can find it on google-earth?

Mate I also need to know how high it is. If u have an admiralty chart it will have the height of the light on it or alternatively it will give u the distance at which the light can be seen. I can work backwards from that.

An existing structure would be ideal if it produces the distances required.

regards
Ronj