Any recommendations- VHF aerial

Tintin

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Hi all,

Am gonna be replacing my two masthead VHF aerials.

What's the recommendations now that Salty John is no longer in business?

Thanks
 
I think it a bad idea to have 2 VHF antenna on the top of one mast. Even not connected an antenna can affect the radiation of the active one. Far better (on a sailing boat) to have one antenna on stern rail. This means your standby antenna is available in case of loss of mast. But also means it can be used for AIS. My main antenna is on the stern rail and while range is obviously less than mast top it works very well. (On a trailer sailer, mast is taken down each winter so much easier with no wiring in mast.) ol'will
 
I think it a bad idea to have 2 VHF antenna on the top of one mast. Even not connected an antenna can affect the radiation of the active one. Far better (on a sailing boat) to have one antenna on stern rail. This means your standby antenna is available in case of loss of mast. But also means it can be used for AIS. My main antenna is on the stern rail and while range is obviously less than mast top it works very well. (On a trailer sailer, mast is taken down each winter so much easier with no wiring in mast.) ol'will
Indeed, what a great number of us have, but now Ofcom dictates we have to do calculations to define the safe distance from the aerial. We have to do it for masthead aerials too but for yachts with a 25W vhf set that's just silly.
 
I am also using a spare aerial on the stern as discovered a couple of years ago that the mast aerial was missing... just the antenna so got another from salty john, just before he closed but still have to fit it - didn't bother last year as didn't get out of the river. But that means going up the mast - which I'm not keen on doing after my knee op.
 
I think it a bad idea to have 2 VHF antenna on the top of one mast. Even not connected an antenna can affect the radiation of the active one. Far better (on a sailing boat) to have one antenna on stern rail. This means your standby antenna is available in case of loss of mast. But also means it can be used for AIS. My main antenna is on the stern rail and while range is obviously less than mast top it works very well. (On a trailer sailer, mast is taken down each winter so much easier with no wiring in mast.) ol'will

Agreed, 2 antennas in close proximity will have a gain in one direction and nulls in another. It will be a lottery as to whether it works when you want it to.
 
There is also a risk of a radio or AIS being connected to the second antenna. I made an emergency antenna to the Ham Slim design using 300 ohm window ladder constructing and then filling it into PVC plumbing pipe with caps at ends. Very compact easily stored on a shelf in the fore cabin and works from a flag haliard or just propped up at a safe EMF distance. I twweked the dimensions slightly so it copes with ham and marine VHF at less than 1.5 SWR. Here is a link to a calculator.

Slim-Jim antenna calculator – M0NWK
 
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