chuzzlewit
Member
At what range would you expect AIS data to appear on your screen? The aerial is mast-head (40') and shared via a splitter with the VHF. Mine manages no more than 12 miles.
AIS
- Thread starter chuzzlewit
- Start date
MidlandsOnSea
New member
I believe AIS is line-of-sight like VHF, so that sounds about right.
CPD
Well-known member
That is my understanding (line of sight) too, although you should be able to achieve more than 12 miles. I am expecting (hoping !) to achieve that with a pushpit mounted 1m whip aerial, so would have thought you should be getting more. Connections ?
whipper_snapper
New member
Given that most ships will also have their AIS transmitting antenna high up, you should achieve over 12 miles, but not hugely more. You can work it out from 'dipping distances tables' in your almanac.
I reckon that 40' mast to ship antenna 100' up gives you a dip distance of 19 miles.
The first thing I would do is throw away the splitter; why compromise 2 important systems with a box of tricks and a bunch of extra connections? Mounting your AIS antenna on the rail will give a small reduction in range (10' rail to ship 100' ASL gives 15 miles), a more robust installation and a spare antenna.
I reckon that 40' mast to ship antenna 100' up gives you a dip distance of 19 miles.
The first thing I would do is throw away the splitter; why compromise 2 important systems with a box of tricks and a bunch of extra connections? Mounting your AIS antenna on the rail will give a small reduction in range (10' rail to ship 100' ASL gives 15 miles), a more robust installation and a spare antenna.
Salty John
Active member
The formula is D = 1.23 (root H1 + root H2), H is height of the two antenna's and is in feet, D is in n.m. , confirming your dip distance.
I agree about the splitter.
I agree about the splitter.
chuzzlewit
Member
Thanks everybody. The splitter goes.
steve6367
Member
Have just fitted the Easy AIS and splitter on my L33 - from Cobbs Quay in Poole it picks up targets about 35 Nm away.
Steve
Steve
jimg
New member
[ QUOTE ]
At what range would you expect AIS data to appear on your screen? The aerial is mast-head (40') and shared via a splitter with the VHF. Mine manages no more than 12 miles.
[/ QUOTE ]
12 miles is enough warning anyway? /forums/images/graemlins/confused.gif
At what range would you expect AIS data to appear on your screen? The aerial is mast-head (40') and shared via a splitter with the VHF. Mine manages no more than 12 miles.
[/ QUOTE ]
12 miles is enough warning anyway? /forums/images/graemlins/confused.gif
davies
New member
Knowing about a pirate at more than 12 miles would be good, but he probably wouldn't be doing AIS.
steve6367
Member
Although limited use........it is very interesting to watch........well for me anyway - maybe I should get out more!
Oldhand
New member
... and I have had 25nm over the top of the IOW with an Easy AIS splitter when surrounded by masts in a Solent marina.
chuzzlewit
Member
Limited use? It got me through the busy channel shipping lanes when unexpected fog descended last week. Radar with MARPA did not give such a clear picture of the situation.
tcm
...
yes, well over 20nm for first hit. There again, sometimes under 10nm...
