What Cheap AIS test aerial (receive only)

[Minerva]

My boat is a 3 hour drive away and I have just bought a Nasa AIS engine to feed into OpenCPN via an NMEA to USB connection via an Arduino. (parts ordered and on way).

I'd like to check that I've got the set up & coding correct by driving the 15mins to the coast nearest my house which is within spitting distance of a working port which will have lots of AIS targets to pick up.

To test this rig in my car, what's the cheapest way to rig up an aerial to receive some AIS targets with say a 1 to 3mile radius? Ideally something like a stubby or free standing arial I can stick on the car roof without looking too much of a plonker.

Thanks

 

[NickRobinson]

Strip 18" of screen off a patch lead so the core points up and the screen down. Vids on YT
I've been using this setup alllast season from the crosstree and getting good results on Tx/Rx voice
eg-

 

[Rappey]

My ais picked up targets to one mile with no antenna so any wire in the back has to be an improvement

 

[Plum]

My boat is a 3 hour drive away and I have just bought a Nasa AIS engine to feed into OpenCPN via an NMEA to USB connection via an Arduino. (parts ordered and on way).

I'd like to check that I've got the set up & coding correct by driving the 15mins to the coast nearest my house which is within spitting distance of a working port which will have lots of AIS targets to pick up.

To test this rig in my car, what's the cheapest way to rig up an aerial to receive some AIS targets with say a 1 to 3mile radius? Ideally something like a stubby or free standing arial I can stick on the car roof without looking too much of a plonker.

Thanks

Similar to the posting above. I made my receive AIS antenna 5 years ago and have been using it on the boat ever since. I get 8 mile ship range with it mounted 2m above sea level. It was going to be temporary but it was so good it became permanent. Strip the outer insulation for about 75cm from a length of 50ohm coax cable. Now milk the exposed braid back over itself back down the cable on top of the still insulated length leaving the insulated inner core sticking out. Trim the length of braid that is now forming an outer screen to 46cm length. Trim the insulated centre core that is sticking out to 46cm length. Poke the whole 92cm length inside a thin wall stiff plastic tube to keep it straight, put a waterproof cap on the tip and mount vertically. Might work from your upstairs bedroom window if there are no buildings or hills in the way.

Www.solocoastalsailing.co.uk

 

[Minerva]

Similar to the posting above. I made my receive AIS antenna 5 years ago and have been using it on the boat ever since. I get 8 mile ship range with it mounted 2m above sea level. It was going to be temporary but it was so good it became permanent. Strip the outer insulation for about 75cm from a length of 50ohm coax cable. Now milk the exposed braid back over itself back down the cable on top of the still insulated length leaving the insulated inner core sticking out. Trim the length of braid that is now forming an outer screen to 46cm length. Trim the insulated centre core that is sticking out to 46cm length. Poke the whole 92cm length inside a thin wall stiff plastic tube to keep it straight, put a waterproof cap on the tip and mount vertically. Might work from your upstairs bedroom window if there are no buildings or hills in the way.

Www.solocoastalsailing.co.uk

Brilliant, that’s worth a shot. Thank you!

 

[lustyd]

when I was doing similar in the summer I bought an emergency antenna with cable and case. Its not as cheap but since I didn't have an emergency antenna on board it seemed less wasteful overall

 

[laika]

There's a few old threads on here to be googled about making your own, e.g.:
Making a DIY emergency VHF aerial

Year before last I made up a dipole from a couple of old bits of wire and attached it to a dAISy HAT on a raspberry pi. Its hanging indoors ( rented 1st floor flat: can't drill a hole in the balcony doors) with buildings all round yet still manages to pick up targets 3-5 miles away. I'm pretty ignorant where radio stuff is concerned so if I can solder something workable up anyone can.

 

[zulloboy]

Yes, have a go at making your own. I get ships up to about 15 Nm from my home-brew push-pit-mounted stick, which is about 3m above the water It also got surprisingly good range when I trialled it for the VHF.
A bit of coax, a bit of pvc conduit, a bit of silicone and a few quid saved, that can be spent on whisky instead.