Stubby AIS aerial on wind generator mast?

[webcraft]

Any reason not to mount a stubby AIS aerial in my windgen mast to get a bit of extra height?

Any recommendations for best stubby?

— W

 

[Plum]

Any reason not to mount a stubby AIS aerial in my windgen mast to get a bit of extra height?

Any recommendations for best stubby?

— W

I successfully used a stubby aerial from an old handheld vhf for my AIS receiver, mounted 1.7m above sea level, for many years. I would reliably receive from small vessels at 4 miles and ships at 8 miles. Yes, a bit extra height will give you extra range.

 

[webcraft]

I successfully used a stubby aerial from an old handheld vhf for my AIS receiver, mounted 1.7m above sea level, for many years. I would reliably receive from small vessels at 4 miles and ships at 8 miles. Yes, a bit extra height will give you extra range.

Will the whirly windgen have any effect?

— W

 

[Sea Change]

Our AIS aerial is a not so stubby thing cable tied to the side of the wind gen mast.
We get about 8-10nm range.
It's noticeably less than when we had a masthead whip, which could easily pick up large vessels 50nm+ away. Same AIS unit.
I did also have to make a break in the cable which won't have helped.

 

[William_H]

You could make your own whip out of ss rod mounted and insulated from mast. 17 inches long screen of coax connected to mast. Centre to rod. Mine works great for main VHFl'will

 

[Sea Change]

Our AIS aerial is a not so stubby thing cable tied to the side of the wind gen mast.
We get about 8-10nm range.
It's noticeably less than when we had a masthead whip, which could easily pick up large vessels 50nm+ away. Same AIS unit.
I did also have to make a break in the cable which won't have helped.

Just in case anybody finds this interesting, I've just chopped down the wind gen pole and mounted the AIS antenna on the rail instead. Exact same aerial, cable run, etc. It's actually located slightly lower than before.

The result? Range has gone from under 10nm to over 50nm. Last night I picked up a ship 104nm away. Pretty remarkable for something that's supposed to be line of sight.

Clearly, strapping the antenna to the side of a big metal pole is a pretty terrible idea

 

[Babylon]

Clearly, strapping the antenna to the side of a big metal pole is a pretty terrible idea

I was going to mount mine on top of the custom-made s/s pole that supports the radome mount at the transom (which I don't think would have effected transmission/reception) but I didn't have enough cable length so just mounted it on the pushpit rail below. At this modest height it still picks up AIS data from more than far enough way for all practical collision-avoidance purposes, and I expect that its transmissions would have a similar range.

 

[webcraft]

Interesting.

We are only getting 4 -6nm range with thevAIS aerial strapped to the pole.

Will try putting it down on the push pit.

Any idea how the pole can effect it?

 

[Sea Change]

Interesting.

We are only getting 4 -6nm range with thevAIS aerial strapped to the pole.

Will try putting it down on the push pit.

Any idea how the pole can effect it?

The pole seems to really mess up the aerial. I've moved the aerial about 18" away from the pole and reception went from ~10nm to 50+, with one ship visible at 104nm.

 

[LittleSister]

I mounted a stubby AIS aerial on the pushpit of a couple of different boats, and the range was plenty for me.

 

[Mud Lark]

I've just fitted one of these Shakespeare 818-HA156C-AIS stub antennas on the pushpit, 4 feet above the water. It picks up the Stenna Birkenhead to Belfast ferry at 10 miles, various fishing vessels at around 5 miles. I'm using it with a Quark AO24 and Marine Navigator.

 

[st599]

Is the stubby antenna designed to operate against a ground plane? The pushpit is a better ground plane than the pole.