VHF antenna installation

[Docktor]

Is there an obvious way to install an external VHF antenna to the roof of a Merry Fisher 625?

The wheelhouse roof appears to be a double-skin GRP construction. The anchor light wiring travels within the cavity. The wiper wiring runs up the centre pillar of the windscreen but exits at the top of the pillar through a grommet as the wiper motor is outside of the roof. And the nav light, which is mounted on the front of the centre pillar of the windscreen seems to be the only accessible point to the centre pillar but it's sealed with sealant.

I was told that some Merry Fishers conduit wiring through the roof grab rails - but this does not seem to be the care in my boat.

Any help would be hugely appreciated!

 

[neale]

Having never worked on one I can't help, but I am sure a Merry Fisher dealer would. They must fit kit to these all the time. Not sure who your local one is in Ireland, but Sea Ventures in the Hamble should be able to help http://www.sea-ventures.co.uk/

 

[Docktor]

Thanks Neale - have been in contact with one MF dealer in Ireland and one in the UK both of whom asked if I had bought the boat from them or wether I was a current customer - before telling me that I would have to bring my boat them to have the installation done!!

Another dealer in the UK told me about the roof grab rail being a solution on some models - a welcome change from the MF policy of secrecy that I had experienced up until then!

They're a popular boat and I assume someone on the forum has done this installation without ruining the roof!

 

[William_H]

The typical VHF whip of about 1.5 metres long in f/g tube does not need a ground plane for correct operation so is the type you should use. ie not the 1/4 wavelength about 17 inch long wire whip which does need a ground plane. A ground plane is the other half of the antenna circuit typically a car roof, radiating wires or ali mast. In the case of the car roof it should be mounted in the middle of the roof.
if you have as said, a f/g whip with circuitry inside to emulate a ground plane then the antenna is suitable for a f/g roof of a mobo. Further it does not need to be mounted in the middle but will be fine on the sides or front of the cabin top. (just in case OP was under a misapprehension. from OP description just above the nav light and using the nav light wiring as a mouse to pull the cable through might be my best suggestion. good luck olewill

 

[KAL]

The typical VHF whip of about 1.5 metres long in f/g tube does not need a ground plane for correct operation so is the type you should use. ie not the 1/4 wavelength about 17 inch long wire whip which does need a ground plane. A ground plane is the other half of the antenna circuit typically a car roof, radiating wires or ali mast. In the case of the car roof it should be mounted in the middle of the roof.
if you have as said, a f/g whip with circuitry inside to emulate a ground plane then the antenna is suitable for a f/g roof of a mobo. Further it does not need to be mounted in the middle but will be fine on the sides or front of the cabin top. (just in case OP was under a misapprehension. from OP description just above the nav light and using the nav light wiring as a mouse to pull the cable through might be my best suggestion. good luck olewill

Or drill a suitable-size hole through the roof and install a deck cable gland for the cable to run through. Straightforward, neat and waterproof.