Two fixed VHF stations

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Paul&Ness

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A quick question regarding fixed VHF. Are there any technical reasons why I couldn't have two fixed DSC VHF units fitted, one at the lower helm and the other on the flybridge? I have two antennas fitted, one is a dummy in that it has no co-axial cable connected. I currently have a discontinued Icom fixed VHF at the lower helm and a discontinued command mic for the upper helm. The command mic doesn't work and I like the idea of having a redundant system so this may be a good time to put another fixed VHF unit up top. There are a number of affordable DSC VHF units on the market that would suffice and cheaper than the cost of any command mic's... I have handheld VHF for the tender and the grab bag etc but it doesn't have the range of the fixed units. So back to the question, is there a technical reason why I couldn't have two fixed VHF units operating? :)
 
And you will need to cancel DSC alerts on each and may get more feedback / interference if the aerials are close.
 
Perfectly ok, with 2 aerials and same mmsi. If you wanted to be super safe you could power the upstairs one with a local 12v battery that would take longer to be immersed if you sank. And you'd need charging for it of course - a local battery charger or a splitter diode or if lucky you might have slave output off your existing charger
 
The radio which came with my boat is non DSC type , but not particularly old and good quality. My plan is to fit an additional radio - with DSC . No point in removing a perfectly good radio.
The black box type radios with two mikes are quite a neat solution where space on the dashboard is limited - but expensive.

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MartynG said:
The radio which came with my boat is non DSC type , but not particularly old and good quality. My plan is to fit an additional radio - with DSC . No point in removing a perfectly good radio.
The black box type radios with two mikes are quite a neat solution where space on the dashboard is limited - but expensive.

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I believe if you have them listening on the same channel you will get feedback when you transmit but I think it is an excellent idea in terms of backup and safely.

I have the battery backup that JFM mentions and if you are interested I will get a list of the parts.

Andrew
 
How would the DSC system work with two radios replying simultaneously (ack message) with the same MMSI number?
Wouldn't this cause problems?
I'm not saying don't install two radios, I think it's actually a good idea and if done correctly will give you some redundancy but having two with the same code on at the same time I'm not so sure.
Would be interested in hearing of anyone using this set up and how it works in practice. One set left switched off maybe?
 
Oscar24 said:
How would the DSC system work with two radios replying simultaneously (ack message) with the same MMSI number?
Wouldn't this cause problems?
I'm not saying don't install two radios, I think it's actually a good idea and if done correctly will give you some redundancy but having two with the same code on at the same time I'm not so sure.
Would be interested in hearing of anyone using this set up and how it works in practice. One set left switched off maybe?
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I have the main DSC radio on the boat and an ICOM DSC handheld as well that has a different MMSI number.
 
Wouldn't necessarily have both VHF sets on at the same time... easy enough to turn on and off as required. We tend to use the flybridge most of the time!
 
Would be interested in your list of parts if possible :) I like the idea of the dedicated battery backup and as someone else suggested, positioning the battery higher than the main battery bank. I could I suppose mount this additional battery under the flybridge consul or in the main carbon tucked away so that it doesn't degrade too much in the winter months.
 
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