Splitter recommendation?

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Ric

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Anybody got a recommendation for a VHF splitter? Or at least makes to avoid?

I bought a Glomex RA111 antenna for my AIS but it is rubbish - the AIS works almost as well without it attached! I am going to have to fit a splitter from my masthead antenna, which I had hoped to avoid.
 
Not sure about splitters but I wonder what is your definition of rubbish? I have a Digital Yacht AIS and their purpose built AIS antenna on my pushpit which they recommended rather than a splitter. From my mooring in Gosport I can pick up the larger ships moored at Fawley and in Southampton docks which I consider more than adequate. However,I did have an issue with the first antenna supplied which was dealt with very swiftly so it might be worth trying an alternative to see if your Glomex is faulty.
 
I too bought the Glomex (splitter) and it is rubbish! Much to much interference with the radio, glad to hear it was not just me complaining. I sent mine back and got a new on in its place but it is equally bad, so l too am looking to replace with something that works!

I also bought the receive only Digital Yacht 100 and this had to go back too. It worked for about a day and then gave up. I sent it back and they said they had tested it for 24 hours, but when put back, nothing! What to do.....

Probably fork out for a separate aerial...
 
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The Glomex RA111 is only 1dB gain - pretty much worse than a bent coathanger! 1m whip aerials for sailing boats are 6dB - and that's a logarithmic scale. If mounted low down the range is likely to be a couple of miles at best. Splitters which split broadcast FM from marine band VHF seem to work OK, but AIS frequency is adjacent to the VHF band so may be more difficult to find. Is there a reason why you don't want to put a second masthead aerial in? That would also give you a spare for the VHF. Can anyone confirm that the VHF shouldn't cause damage to the AIS when transmitting?

Rob.
 
How would you separate the two antennas? Unless you accept a non-omni radiation pattern which is far from ideal.

It's not really a redundant install - most major faults - dismasting, lightning strike - would take out both.

With a NASA ais and a cheap rubber ducky antenna on the pushpit, the last install I did can see vessels upto 20 miles away (depending on size).
 
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richardbrennan said:
Not sure about splitters but I wonder what is your definition of rubbish? I have a Digital Yacht AIS and their purpose built AIS antenna on my pushpit which they recommended rather than a splitter. From my mooring in Gosport I can pick up the larger ships moored at Fawley and in Southampton docks which I consider more than adequate. However,I did have an issue with the first antenna supplied which was dealt with very swiftly so it might be worth trying an alternative to see if your Glomex is faulty.
Click to expand...

I intended to put the Glomex antenna for the AIS on the pushpit, and use it also as an emergency VHF antenna.

However, having spent the best part of the day fiddling around with it, the range seems less than a mile or so, and some of my AIS data is not even transmitting (eg only MMSI would show up on MarineTraffic).

As soon as I plugged in my VHFs masthead antenna, I could pick up ships about twenty miles away, and some shore stations 200 miles away. My boat's name also popped up fairly instantly on MarineTraffic.
 
It must surely be the wiring. I get AIS contacts from 20 nm and my aerial is inside the boat. Best place for it. Easier to fit, no leaks, still works if the mast comes down and range is more than needed for the job.
 
Ric said:
I intended to put the Glomex antenna for the AIS on the pushpit, and use it also as an emergency VHF antenna.

However, having spent the best part of the day fiddling around with it, the range seems less than a mile or so, and some of my AIS data is not even transmitting (eg only MMSI would show up on MarineTraffic).

As soon as I plugged in my VHFs masthead antenna, I could pick up ships about twenty miles away, and some shore stations 200 miles away. My boat's name also popped up fairly instantly on MarineTraffic.
Click to expand...

Unless you are doing these tests in a marina, or well up the river, I would say you had a fault in either the antenna or the coax connection.
VHF is pretty much line-of-sight, so testing on the mooring surrounded by a lot of other moored yachts can give poor results compared to out in the Solent etc.
The height of the antenna on the ships makes it all work.
 
Ex-SolentBoy said:
It must surely be the wiring. I get AIS contacts from 20 nm and my aerial is inside the boat. Best place for it. Easier to fit, no leaks, still works if the mast comes down and range is more than needed for the job.
Click to expand...

Are you using a Glomex RA111?
 
Against my better judgement I just recently fitted a Glomex splitter along with a Digital Yachts AIS on a "let's try it and see" basis for a customer as he already bought them, I wasn't hopeful but tried to make the best of what I thought was going to be a bad job by using proper install regime with shielded cables, proper grounding of data cables and the like, changed the BNC connector on the splitter for a PL259 instead of using an adaptor etc. The VHF is only on a coach roof but a radio check (R&T), VHF interference levels and AIS targets are all at acceptable levels despite the boat being surrounded on all sides by buildings. All that said I would still go the separate route normally as that, though it worked, is a sample of only one
 
I'm trying to avoid a splitter if I can, but the results with a separate Glomex RA111 antenna on the pulpit seem very poor given my testing so far.

Possibly it is a poor connection with the solderless coax terminals that Glomex provide, or perhaps it is because my testing so far has been done in port. Tomorrow I'll solder the terminals and try hauling the antenna to the masthead on a halyard.
 
You shouldn't have any problems with AIS transmission or reception with the antenna mounted on the pushpit or a radar arch. If it is masthead mounted, you need to observe a minimum 1 metre vertical displacement with your VHF antenna
 
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