VHF DSC

Mike has it on the nail there
It has been made for those who "have to"

It is no diff than all the useless banter on CH16 on a bank holiday weekend.
Only thing is you can't turn it down.
At least with DSC you can get your Mayday out which you can't if Fred and Bob are sorting out which pub to have lunch at!

There is good and bad in everything I guess.

Regards

<hr width=100% size=1>Jon Brooks Icom UK Ltd. 01227 741741
 
Just returned from the Channel Islands, where the alert/ alarm is every hour or so, preceding "securite" broadcasts from Cherbourg Traffic Control.

<hr width=100% size=1>"I am a bear of very little brain and long words bother me..."
 
In case it clears the situation a bit this is what the new ITU IEC62238 says for Class D. I only have the ultimate draft of the standard, not the published version, but I do not believe any important changes took place in the final version). I have paraphrased and shortened.

- Acoustic alarm and a visual indication, activated automatically when distress or urgency has been received. Not to be possible to disable these alarm circuits.

- Other categories - acoustic alarm and a visual indication, activated automatically on receipt of calls of categories other than distress and urgency. Not to be possible to disable the acoustic alarm circuits.

- Cancellation of alarms is to be automatic after 2 mins if not already manually cancelled.

- Alarm Power - The acoustic alarm shall be loud enough that is clearly distinguishable, but not interfere
with, radiotelephone communications. If not manually cancelled within 10 s, the power should rise to a level of at least 80 dB(A) at a distance of 1 m from the equipment before automatic cancellation.

I think those are all the relevant bits and it is clear that on a small vessel 80db is a bit of a pain (literally). Note that it is incorrect to state that this standard is oriented to large vessels (they will not be Class D), but will certainly apply to small commercial vessels.

Finally, what the EU/UK is going to require I do not know, as far as I am aware they have not accepted the new Class D standard which has requirements roughly in line with the sets the rest of the world could buy for the pleasure market ie it is substantially less severe requirements than the old Class D.

On my own set (an international Icom) it is possible to disable the DSC and only maintain a audio watch on CH16 and scan.

John

<hr width=100% size=1>
 
Where does the alarm sound?

If the alarm comes out of the loudspeaker then you can transfer it to an external loudspeaker - I hope where it can be dealt with by the watch keeper.
If its on a separate squeaker then maybe one can get at that and tone it down - if only by covering it with chewing gum.

<hr width=100% size=1>Roger
 
Re: Where does the alarm sound?

Hi does anybody know if its possible to test the DSC in any way, it would be good to know that when I send a distress call the set is in fact sending a signal that can be received. Up here in the NW as yet I have not come across anybody with a DSC MMSI number that I can send a DSC call too, I suppose iits possible the CG at Liverpool will have a MMSI for taking individual calls, come to think of it they must have so we can give them RT calls. Isuppose we call them on DSC then transfer to 68 or which ever chanel they request.
Mike

<hr width=100% size=1>www.sailingforfun.co.uk
 
Re: Where does the alarm sound?

You mite find these helpfull.

HM COASTGUARD MMSI ALLOCATIONS

002320001 MRSC SHETLAND

002320002 MRSC PENTLAND

002320004 MRCC ABERDEEN

002320005 MRSC FORTH

002320006 MRSC TYNE TEES

002320007 MRSC HUMBER

002320008 MRCC YARMOUTH

002320009 MRSC THAMES

002320010 MRCC DOVER

002320011 MRSC SOLENT

002320012 MRSC PORTLAND

002320013 MRSC BRIXHAM

002320014 MRCC FALMOUTH

002320016 MRCC SWANSEA

002320017 MRSC MILFORD HAVEN

002320018 MRSC HOLYHEAD

002320019 MRSC LIVERPOOL

002320021 MRSC BELFAST

002320022 MRCC CLYDE

002320023 MRSC OBAN

002320024 MRSC STORNAWAY

002320060 JERSEY RADIO

002275200 CROSSMA JOBOURG (Cap de la Hague)

002275300 CORSEN (Brest area)

002050480 OOSTENDE

002500300 DUBLIN

<hr width=100% size=1><A target="_blank" HREF=http://powerskipper.mysite.freeserve.com/>http://powerskipper.mysite.freeserve.com/</A>
Julie
 
Re: Where does the alarm sound?

Yes you can test your DSC set. Firstly most manafactureres handbooks advocate testing the distress function once a year by pulling back the cover and tapping the distress button once, your screen should then display the distress message that would be sent if you held the button down for a further five seconds. (obviously do not hold the button down after the initial tap).

To test the DSC function itself try calling your Coastguard digitally next time you need to call them. Liverpool CG MMSI is 002320019. I would reccomend anyone who has installed new equipment send a test message to ensure the equipment works.

On the matter of people turning of their DSC sets due to the alarms, this results in the same problem as when people turned of or down their sets due to excessive voice calling. DSC is supposed to solve this problem by reduciong voice calling on Ch 16. The best solution is as already described to fit an external cockpit speaker so that off watch crew are not disturbed when sleeping.

I myself am a fan of DSC as the safety alerts that everyone is complaining about are sent for our benefit to announce a nav warning, gale warning or maritime safety information broadcast

<hr width=100% size=1>RYA Courses in the Solent at http://www.stormforce.biz
<P ID="edit"><FONT SIZE=-1>Edited by Doug_Stormforce on 05/05/2004 17:39 (server time).</FONT></P>
 
Re: Where does the alarm sound?

If you fit a cockpit speaker you cannot then hear it below at the set (the set speaker is automatically disconnected), to get round this you fit TWO extensiion speakers one below and one in the cockpit. Then you are back to square one and off-watch crew below still get the full alarm volume as often as the warning is repeated. If this happens I'm afraid the set will be switched off, maybe I'll get the (non-DSC) handheld out of the grab bag, maybe not....

I agree I want to hear the alerts. I don't agree that they should be so loud (and may be repeated in some cases every 15 minutes) that they would wake the dead never mind sleeping crew. This is a bigger problem perhaps on yachts because they are more often at sea at night and do not have 2 girt great diesels running anyway!

One friend has now refitted his old non-DSC set alongside the new, just for night use. Counter productive or what?



<hr width=100% size=1>
 
Re: Where does the alarm sound?

I'm also a fan of DSC, but until you've experienced incessant alerts you probably won't appreciate the problem.

On my set (Simrad RD68) plugging in an external speaker doesn't disable the internal speaker so your suggested solution wouldn't work.

<hr width=100% size=1>
 
Re: Where does the alarm sound?

I'm with Robin on this.

Crossing the channel last week, CROS Jobourg puts out securité msgs very frequently. These are NOT preceeded with a DSC alert. If they were it would be a nightmare. Maybe the answer is for the CG, etc, to save DSC alerts for distress and genuinely urgent traffic only, not for routine warnings such as weather, maritime info, etc.

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>
 
Re: Where does the alarm sound?

Absolutely. The real problem though is that big brother has decided we, the user, cannot be trusted so the alarm volume is fixed at a level that would wake the dead in the engine room of the high speed Condor Ferry (audible range 10mls in the Channel) with their DSC set on the bridge.

<hr width=100% size=1>
 
Re: Where does the alarm sound?

I have to say that I think it's telling that both Mike Martin and Jon Brooks are RIB enthusiasts. When I owned a RIB, it was impossible to keep any radio watch even at full volume. Hence they don't see any problem with full on alerts, it seems.

Disappointing that they can't consider a broader case and put themselves on board a short-handed sailing vessel at night.

<hr width=100% size=1>
 
Re: Where does the alarm sound?

That thought had crossed my mind too, it is a different world. I guess many flybridge power boats too might have a separate radio up top? Certainly you wouldn't run up & down from a flybridge to answer radio calls/alerts, which is precisely what most of us on yachts have to do, the set is below and at best there is an external speaker up top in the cockpit.

I may well put our old set back somewhere too for night use, we have a 2nd (spare) aerial in place on the gantry anyway so if I can rig an easy way of switching the speaker leads over at night that might be the way to go.

Camels committees and horses seem to come to mind!

<hr width=100% size=1>
 
Re: Where does the alarm sound?

With all due respect, I have done that as well.

It is just my chosen time on boats at this time is on a Rib.

It is not down to Mike or I or even my company.
It is down to the IMO that make the rules
We make the kit to meet the rules or exceed them.

Mikes mob enforces the rules laid down.

Kind regards


<hr width=100% size=1>Jon Brooks Icom UK Ltd. 01227 741741
 
You must log in or register to reply here.

Other threads that may be of interest

stav
Active antenna AAX5 is it just a vhf antenna?
Replies
3
Views
170
stav
stav
T
Notices to Mariners - Week 50
Replies
2
Views
721
tillergirl
T

Share this page

Top