Ais ariel on the pushpit

[steve yates]

Looking to add ais to my ipad, got relevant bits from foums for sale section and now just need to add an ariel on the pushpit. Any reccomendations? Its for my little boat, the bradwell 18, for dotting about the thames estuary and east coast in general, mainly to see whats coming to hit me and dont really need to know about boats 30 miles away.
Thanks.

 

[Dellquay13]

I bought a stubby antenna for my pushpit, a Shakespeare HA156C-AIS heliflex v-tronix tuned to the AIS end of the spectrum. 162Mhz.
I haven’t fitted it though, as I changed my mind and fitted an EasyAIS splitter on my masthead antenna instead.

 

[Plum]

Looking to add ais to my ipad, got relevant bits from foums for sale section and now just need to add an ariel on the pushpit. Any reccomendations? Its for my little boat, the bradwell 18, for dotting about the thames estuary and east coast in general, mainly to see whats coming to hit me and dont really need to know about boats 30 miles away.
Thanks.

I have a stubby from an old handheld vhf mounted just over 1m above water level and gives me a reliable range of 5 miles and mostly 8miles for ships which is perfectly adequate for me.

Www.solocoastalsailing.co.uk

 

[FWB]

I have stubby AIS tuned antenna mounted below. Works perfectly.

 

[William_H]

An antenna in it's simplest form and quite efficient consists of 17 inches of stiff wire connected to the centre of the coax cable. The outer is connected near that same point to a large grounded structure. Mast or pushpit. Called a 1/4 wave length whip. Very simple the tricky part is to fabricate an insulator to support the rod and provide robust attachment to the rail.
I had an open end to the pushpit corner post and was bale to feed the cable up through the post. I pushed into the open post a piece of plastic conduit 15cms long The braid of the cable came out a hole in the conduit to attach with a lug to a screw through post. I flattened the end of the stainless steel rod so I could drill a hole through for a screw and lug onto coax centre. The rod was then centred and held in place by resin. Note length of the piece of coax centre from exit of cable to the rod should be included in the 17 inch length. If you don't have a post with open end you could fit another SS tube clamped next to corner post which could raise the antenna higher. Every bit of height is good. I use mine not for AIS but for VHF communication. Works well and no cables in mast. ol'will

 

[doug748]

Like FWB I use a stubby on the pushpit and think it's fine for what you want.

I also have a back up as described by William_H.

1) Take a length of coax and cut off 17in of the outer insulation, exposing the braid.
2) At that point 17in from the end of the wire work the braid open and fish out the inner plastic core. Pull it through so that you are left with the inner 17in and the floppy braid also 17in. ( Copyright PBO circa 1985 )

Now the crafty bit. If you work the two 17in lengths under the frame of the spayhood forming a tee shape you have an horizontal dipole aerial. Sometimes the sleeves of the cover can completely hide the wires. A BNC connector on the end of the coax completes the job, this works well for me as my AIS is under the sprayhood anyway

.

 

[john_morris_uk]

Although I understand why people think that reduced range is ok, I quite like the thought that we appear on ships AIS as far away as possible. (I’m assuming Class B transmission and reception) Ships invariably take action to keep clear of sailing vessels so why not make their lives easier by not popping up on their display from only a few miles away because you’re on an inefficient antenna low down?

 

[langstonelayabout]

I use one of these on my Konsort’s pushpit: Glomex 1.5m Fibre Glass Antenna and it has always worked well. CG could see me well south of Poole bay on a bad day. Very happy with it.

 

[Daydream believer]

My aerial sits one one half of a 2.4 metre telescopic sailboard boom. I cut the first part with the sharp bend off & that left a fairly straight section with a telescopic bit out of that. It is clamped to the pushpit with 2 "U" bolts set diagonally. The slight curve at the base is handy as it turns the end into the deck gland which is set slightly inboard on a flat section of deck.
Normally the unit is not extended & gives at least 10 mile range. I have been contacted by ships I cannot see. In fog I raise the aerial up by extending the boom to give a few more miles range.
There are loads of sailboard bits around in people's garages, so one can normally get one easily enough. The aluminium is usually a good quality anodised & strong.
My echomax radar reflector sits on the other half of the boom

 

[GHA]

One thing to bear in mind, range changes all the time so if anyone says "I pick up targets 100Nm away" it's pretty much meaningless apart from there and then. And easy to log & plot if you have a raspberry pi, if anyone is interested with time & antennas to do some testing I'll post the node red flow which does the work.
For pottering around the east coast recieve on push pit sounds fine.

This is sort of fairly common on the Algarve, though quite often less. Sometimes down to the Canaries when ducting is strong.


UK you may well get less ducting, marinetraffic receiving station data can be handy to look at, it can show up how well or not the ptopogation is that day.

Ducting seems to turn on and off pretty quickly..

 

[bitbaltic]

I had a pushpit stubby (the usual Shakespeare) for 10 years for my receive-only AIS. It was torn off the boat 3 times in 9 years by neighbouring boats either in marinas when my boat was unattended or once before the start of a race where we were rafted up fore to aft against another boat that laid its spinnaker lines inside our pushpit during the raft and we didn’t notice when pulling off. Last season, I fitted a 1m pole to lift it away from such hazards and at end of season the marina berthed a crappy mobo next to us owned by a bloke (I was later told) ‘didn’t know how to drive it on coming in’. The gunwales of the mobo were exactly level with the new raised height of the stubby and I came back to our (again unattended) boat to find the whole apparatus ripped off presumably by a loose line and the cable stripped out of the stubby.

I fitted a comar splitter that I’d got off eBay for 50 quid and cured the problem. No more stubby problem and a great increase in AIS range.