Daydream believer
Well-Known Member
Seriously?
On the other hand, if it looks like a duck and quacks like a duck ...... guess what?
Richard
Then she must be a witch - Burn her:encouragement:
AIS aerial vs AIS/VHF splitter
- Thread starter Champagne Murphy
- Start date
Then she must be a witch - Burn her:encouragement:
RichardS
N/A
I know that you've quoted me in your post ... but after that I'm completely nonplussed. Did you intend to quote one of the forumites who was ridiculing you for using Google 'cos neither of those were me.
Richard
TSB240
Well-Known Member
Is there also a another potential disadvantage of using a highly placed AIS receive at the masthead?
I understand that class B transmissions are restricted in preference and give priority to class A communications.
So scenario is you may be picking up many more Class A Targets with a mast top mount at distances that are irrelevent to your current and potential collision course with a more local class A or B target.
Is it possible that these long distance class A targets could restrict the ability of your class B to give an updated position to a potentially much closer Class A or B contact?
I have seen the effect of my class B transmissions being delayed by a concentration of class A signals quite close to my location.
This was only because of a software fault in my transponder. It started to show our AIS transmitted boat position as a shadow and at one point was at least 1/4 of a mile behind our actual position.
This is in a boat only doing 5 knots and with a pushpit mounted antenna!
I suspect in crowded shipping lanes I would prefer my chances with a pushpit mount! Especially if I am going to be using the VHF to check on any proposed actions of potential danger?
I understand that class B transmissions are restricted in preference and give priority to class A communications.
So scenario is you may be picking up many more Class A Targets with a mast top mount at distances that are irrelevent to your current and potential collision course with a more local class A or B target.
Is it possible that these long distance class A targets could restrict the ability of your class B to give an updated position to a potentially much closer Class A or B contact?
I have seen the effect of my class B transmissions being delayed by a concentration of class A signals quite close to my location.
This was only because of a software fault in my transponder. It started to show our AIS transmitted boat position as a shadow and at one point was at least 1/4 of a mile behind our actual position.
This is in a boat only doing 5 knots and with a pushpit mounted antenna!
I suspect in crowded shipping lanes I would prefer my chances with a pushpit mount! Especially if I am going to be using the VHF to check on any proposed actions of potential danger?
PhillM
Well-Known Member
So are you telling me getting a cheap tranciever and using a stubby I side the wooden cabin won’t work? I ask because I don’t have a splitter atm nor a push pit on which to mount a second aerial.
moomba
N/A
I know that you've quoted me in your post ... but after that I'm completely nonplussed. Did you intend to quote one of the forumites who was ridiculing you for using Google 'cos neither of those were me.
Richard
Hee Hee yes your right again It must be a mental connection I have to you this the second time I need to apologizes
My most humble sorry
moomba
N/A
It does seem in very busy shipping lanes Class A and B can be restricted due to to many signals
moomba
N/A
Can you put it on you cabin roof or to the side of it, it uses digital signals not analogue but still is restricted by height and line of site, the higher it is and further away from the VHF and in clear space the better the signal and reach
PaulRainbow
Well-Known Member
The GPS receiver should work inside, but i can't see you getting much of a range with the VHF antenna inside.
PaulRainbow
Well-Known Member
Of course, which is another reason the sillyness of picking up every vessel with 200 miles is, erm, sillyness.
lw395
Well-Known Member
The VHF aerial for the AIS would 'work' to some extent 'indoors'.
But there is not much point in AIS if you are not reasonably confident you will receive every ship that matters. And if you're transmitting AIS, you want to be doing a proper job, not messing everyone else around with poor transmissions.
It's not that hard to put an AIS aerial on a 6ft post at the stern.
RichardS
N/A
Although if installing a post and cable is "not that hard", then installing a splitter has to be "child's play".
Richard
lw395
Well-Known Member
Although if installing a post and cable is "not that hard", then installing a splitter has to be "child's play".
Richard
Indeed.
But I could cobble together a useful post from 'junk' and get a cheap aerial for significantly less money.
If you've already got a stubby aerial, it's tempting to go the post route.
How much are AIS splitters these days?
Pinnacle
Well-Known Member
moomba
N/A
AIS spliters are around 180 to 350 pounds , such variation can be seen as the cheaper versions maybe having more issues in regards to deciphering lots of signals
a VHF/AIS antenna around 35 to 80 pounds but cable would needed to be added but guaranteed no interference from broadcasting the VHF.
Really down to personnel choice as like choosing your lady love
Last edited:
moomba
N/A
I have just got a new tub........
Clearly then it must be a good thread , very informative and pleasant reading
lw395
Well-Known Member
That seems rather a lot, in relation to the price of VHF and AIS transceivers.
TBH, the sensible thing would perhaps be to have all one's needs in the VHF band in one box.
Maybe with all the RF gubbins at the masthead, to avoid the need for heavy, expensive cable.
pvb
Well-Known Member
You've been looking in the wrong places! AIS splitters start from about £40, and indeed the OP in post 1 gave a link to a Glomex splitter for £65. Splitters aren't involved in "deciphering lots of signals", that's what receivers do. A different type of splitter is needed for AIS transceivers, and these start at around £190.
moomba
N/A
I was under the impression I was talking abut AIS transceivers for spltters so that the signals could be deciphered
my apologizes if this was not clear the pricing is therefore about right :encouragement:
pvb
Well-Known Member
The OP was asking about receive-only AIS. Transceivers need a different type of antenna splitter, although a number of transceivers have integral splitters, giving a simpler installation and at possibly less cost than a separate splitter. There's no "deciphering" in any sort of splitter.
moomba
N/A
Agreed but this thread went a little to the far right and it should really have answered the OPS questions