Re: Too many VHF aerials?

Ryan Meador

Hi Mark,

Do you have a Class A VHF?  Those are the type that use two antennas for DSC, but I've never seen one in the flesh -- most recreational boats use Class D, with a shared antenna.

On our boat, we have one antenna on each mast.  The main mast is split between the nav station VHF and AIS, and the mizzen is connected to the helm VHF.  Both VHFs have DSC.  This setup has worked well for us.  If the splitter fails, it's easy to connect the nav station VHF directly to the radio, and I believe we also have a jumper between the helm and nav station so we can swap the antennas to either radio by plugging a few wires (that's what the wire is labeled as by the previous owner... I haven't tried).  And we also have a handheld as a third backup.

I think having the AIS on the main mast for better range outweighs any drawbacks of having a splitter.

Ryan and Kelly
SM 233 Iteration
Boston, MA, USA

On Tue, Jan 7, 2020 at 12:10 PM Thomas Peacock <peacock8491@...> wrote:
Hi Mark,

We also have one VHF on the main mast, and one on the mizzen. Maybe I have misunderstood the configuration, but here is how I think we have it:

The main mast antenna is hooked up to our VHF analog radio. That radio also has a button for DSC (the D standing for digital), but I always assumed that the DSC signal was transmitted via the same antenna as the analog VHF signal, not on a separate antenna. At least, when I installed the radio, there was only one antenna output terminal on the radio, so I don’t see how it would use two antennas.

Our mizzen antenna hooks up directly to the AIS transceiver, no other devices use it. 

If the either VHF antenna failed, we also have a spare antenna on board that could be partially hoisted for elevation.

Tom Peacock
SM 240 Aletes

On Jan 7, 2020, at 11:56 AM, marklesparkle59 <marklesparkle59@...> wrote:

On my main mast there is the main VHF Radio aerial, on the mizzen are the DSC aerial and the Emergency VHF aerial and I would like to add an AIS aerial to avoid a splitter. I am considering replacing the Emergency aerial with the AIS and using a bolt on emergency. How have other owners coped with this proliferation? 

Mark Porter
Sea Hobo
CARDIFF Marine Village

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