Please Recommend a Quality VHF Masthead Antenna

[Ursula pappas]

John
I’m clueless about electronics/tech stuff. Friend getting new system on his boat. I’m across country right now. Want to be able to get extended WiFi service if anchored out a bit. All I need is to be told what to buy to accomplish this. Will write island times. Any other advice appreciated.

[MCilenti]

All,
First, thank you for this thread...I've learned a tremendous amount that will help me as I seek to replace my VHF radio, antenna, cable system (a total system is how I'm thinking about it now).

One question- I assume (hopefully) that my cable is supported throughout the mast and not just hanging. Is there some type of common internal support that most sailboat masts have and is common to the majority of boats or is it highly custom? If there is something common, how can I loosen those supports to thread a new cable through and replace the old one?

Thanks for the help.
Cheers,
Mike

S/V Cymba
1986 Sam Morse Bristol Channel Cutter

[Hartleyg]

Mike,


On every sailboat I've examined, the cable is hanging from the top, and the load is carried with a fairly long "grip" either manufactured (Chinese finger trap looking device) or home-made with wire or cord. Inside the mast, either the cable is run inside a conduit, or (generally on small sailboats) multiple cable ties are put on with the tails attached to keep the cable from banging around inside the mast.
Supporting the cable along the run would require access to the inside, something I've never seen on a sailboat mast. I do recall one big boat that had a long run of lo-stretch line that had the masthead sensor cable, power for the lights and radio cables attached to it - they drew the whole thing out if they needed to replace or repair (it was a 90' mast). Seemed like a good idea to me!



Hartley
S/V Atsa

[MCilenti]

Thanks Hartley!

I'll be doing the work without unstopping the mast so any information in advance of working aloft is a huge help!

Cheers,
Mike

[GTom]

As my masthead is taken by the VHF and don't want a splitter, I am thinking on putting an AIS antenna on my radar pole on the stern.
What's the minimal distance I must keep between the center of the radar dome and the AIS antenna? Do I have to go above the radar dome as well?

[s/v Jedi]

I recommend you put the antenna on the upper spreader ��

[GTom]

Originally Posted by s/v Jedi

I recommend you put the antenna on the upper spreader ��

Sounds obvious, but I thought it would be a good idea to have a backup in case the mast decides to come down.

This one seems interesting:

[s/v Jedi]

Originally Posted by GTom

Sounds obvious, but I thought it would be a good idea to have a backup in case the mast decides to come down.

This one seems interesting:

You will lose most of the range but you need vertical clearance with radar scanner... it is in the radar manual but IIRC one meter minimum (40”).

I would put the antenna on the upper spreader and have an emergency antenna aboard for the very unlikely case of loosing the mast.

[GTom]

Originally Posted by s/v Jedi

You will lose most of the range but you need vertical clearance with radar scanner... it is in the radar manual but IIRC one meter minimum (40”).

I would put the antenna on the upper spreader and have an emergency antenna aboard for the very unlikely case of loosing the mast.

With the AIS I want to achieve 2 things:
- practical navigation: I want to show up on the supertanker's screen in 15 miles in open sea, as they plan their maneuvers about 10miles ahed. No problem, they have 15miles radio horizon even if I am sitting in a dinghy, holding my handheld. Knowing what a 30ft fishing boat is doing 15 miles away has no practical information to me.
- contact with the AIS satellites for offshore tracking: this has nothing to do with antenna height, just the radiation pattern AND the attenuation the signal suffers trough a longer cable, splitter and an additional connector.

Interference is another question though. On a typical arch, used on millions of mobos and quite a few sailing yachts the VHF/AIS gets the full power of the radar lobe, often from a distance of 1', I'd be interested in any real-world experience here...

[Simi 60]

Looking for an AIS/VHF antenna and came across this Glomex one.
Interesting to me as I need more than the usual 5m of supplied cable
Available on eBay and in from the US far cheaper than anything I have found in Australia


https://shop.glomex.it/en/generic/54...supergain.html

Elba AIS is a 3dB gain AIS antenna designed for Sailboats: it’s 970mm / 38” length and very easy to be installed thanks to the supplied “L” bracket. With its black strong fiberglass whip and integrated 20m (66’) RG58C/U coax cable, it’s the best choice to have a stable AIS performance under any navigation conditions.




TECHNICAL SPECIFICATIONS
FREQUENCY RANGE

161,975/162,025 MHz
GAIN AVERAGE 3 dB
IMPEDANCE 50 ohms
POLARIZATION Vertical
SWR <1.4 at 162 MHz
MAX INPUT POWER
50 W

DC GROUND Reads 10K ohms
ANTENNA LENGHT 970mm (38")
ANTENNA WEIGHT 175g (6.2oz)
TERMINATION Cable

I should add my cable run will probably only be around 25ft/7m

[Simi 60]

Also thought this one was interesting




https://www.ebay.com.au/itm/Tram-167...edirect=mobile

[Auspicious]

Originally Posted by Simi 60

Looking for an AIS/VHF antenna and came across this Glomex one.

RG 58 is not very good coax.

Both the antennas you linked to have pigtails with male PL-259 connectors. That is undesirable. A fixed female SO-239 (what you screw a PL-259 into) is best, an inline SO-239 on a pigtail is okay.

[Simi 60]

Originally Posted by Auspicious

RG 58 is not very good coax.

Both the antennas you linked to have pigtails with male PL-259 connectors. That is undesirable. A fixed female SO-239 (what you screw a PL-259 into) is best, an inline SO-239 on a pigtail is okay.

Fair enough.

While not the best our current roof mounted vhf antenna uses the same coax.
We regularly get weather reports from marine rescue over 50nm away which I though was pretty good for vhf.

As I will be chopping 30 feet out of the cable anyway, adding a better connector will be a given.

[Pete7]

How does something like this match if its imported into country?

https://www.saltyjohn.com/product-ca.../metzantennas/

John will also sell any length of RG8 you need. Just bought 5m from him so our AIS antenna could also double as a spare VHF if the mast came down.

Well regarded on YBW.

Pete

[s/v Jedi]

Originally Posted by Simi 60

Fair enough.

While not the best our current roof mounted vhf antenna uses the same coax.
We regularly get weather reports from marine rescue over 50nm away which I though was pretty good for vhf.

As I will be chopping 30 feet out of the cable anyway, adding a better connector will be a given.

I recommend you reconsider your pick and look at the CELmar0-1 antenna.

PDF: https://acantennas.com/sites/default.../CELmar0-1.pdf