[CK]VHFs with tri-watch

[TechnoEngineer]

by selecting tri-watch and then locking the keypad, I can paddle along in relative comfort knowing my radio will pick up any traffic on 16, 6, or the current channel so I will hear general broadcasts, I will hear my group (and any vessels using 6 during the day) and I will hear the forecasts, subfacts and whatever the CG broadcast in a given area.

Which radios do tri-watch?

[MikeB]

Icom, Standard Horizon certainly do.

[Jim]

Icom M71

[Sprucey]

My standard Horizon will "Scan" more than thee channels at the same time. I've never understood the tri-watch function when the Scan function will listen in on more? (I'm a bloke and not too good at reading instructions!)

Sprucey

[TechnoEngineer]

I suspect that the "scan" listens to channels sequentially, whereas the tri-watch would listen to them concurrently. So a "scan" is likely to miss something.

[Grahamd]

I have an Icom M71 with tri watch, but I tend not to use it. Like Srucey not quite sure what is does and not felt the need for it when I can use the scan function to monitor as many channels as I want to TAG.
I think you are probably right Technoengineer in that the scan is sequential. However, it runs between all the channels very quickly, probably not much more than a second. If it finds activity on a channel it stops on that channel until the traffic is fninshed. It also seems to prioritise channel 16, so probably monitors this all the time, but I think you have to set it to scan-dual to get Ch 16 priority.

[MikeB]

I suspect scan uses more energy - but thats just a guess. if nothing else, even in low traffic areas its a nuisance picking up extraneous calls when all I really want to monitor is our designated one. I guess down in somewhere like Southampton Water that need might change though!

[The Shiner]

I suspect that the "scan" listens to channels sequentially, whereas the tri-watch would listen to them concurrently. So a "scan" is likely to miss something.

Yes but you can listen to one transmission at a time!

I've just been playing around with my S/H VHF, and when I highlight the channels I want to monitor (by pressing the "Mem" button) and then press "Scan", it really does scan through the channels fast!
I just highlighted QHM VTS CH16 & CH67, it was really good and was flitting in between transmissions and then scanning very rapidly in between breaks.

Surely that has got to be just as good if not better than Dual or Tri watch? Because you can monitor more channels if you need to.

[TechnoEngineer]

Rich you wouldn't want to hear two concurrent transmissions being interleaved; the point of dual/triple watch is to operate a priority. See here:

http://forums.iboats.com/showthread.php?t=358227

[The Shiner]

Aah, I see.
I just looked at my unit again (and the instructions), it says "PScan" when I push scan which makes it scan 16 every other channel, and I'm presuming it would also overide a transmission on a channel if there was something on 16.
If I hold the button down whilst in scan mode it changes it to scan, with no priority.

It's amazing what you learn when you read the instructions, lol.

[Sprucey]

Mike is probably spot on re: power usage while scanning and is also spot on when he talks about paddling in the Solent, particularly around Portsmouth Harbour entrance. The power thing is not an issue for day or evening paddles but obviously would be if one was away on an extended paddle but you probably wouldn't scan then.

In the winter, we paddle a lot in the dark from the Sally Port beach 100m outside Portsmouth Harbour entrance. Being able to listen to QHM (who sits slightly higher than God in these parts!), Southampton VTS, Ch9 for pilot boat movements as well as CH16 & CH67 gives us a full picture of large ship movements at a very busy time in the evening. Over the course of a regular 1.5 - 2hr evening night paddle there maybe as many as 6 Isle of Wight ferry movements, 2-3 hovercraft transits, 3 cross channel ferry / hi=speed ferries plus other commercial and pleasure boat movements. A busy time!

Using the VHF to let QHM know we are there (he actually knows because we are tracked on IR cameras placed all around the Dockyard!) gives him (often "Her" on the Wednesday evening shift) confidence that we are competent and aware and also gives us good practice with radio protocol and making short concise radio transmissions.

Sprucey