Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 01-11-2019, 09:28   #1
Registered User

Join Date: Sep 2013
Location: Windham NH
Boat: Bristol 29.9 1978
Posts: 105
AIS Transmitter Suggestions

Several years ago I added a McMurdo Smartfind AIS receiver to my boat's electronics. The AIS receiver is tied in with my Uniden UM525 VHF radio and my Garmin 540s chart plotter. This arrangement works very well. I can see all AIS targets within about a ten mile range and I'm prepared for emergency DSC broadcasts in the event of some dire situation.

I have noticed that the number of vessels using AIS transmitters has increased dramatically in the past two years. Since these vessels must also have AIS receivers, it can be assumed that the number of vessels with receivers has also increased. Perhaps it is time to consider adding a transmitter to my own configuration.

Given my current configuration, which I am very happy with, what would be the most efficient and economical way to add an AIS transmitter?
__________________

Homer Shannon is offline   Reply With Quote
Old 01-11-2019, 09:42   #2
Registered User

Join Date: Oct 2015
Posts: 1,613
Re: AIS Transmitter Suggestions

You have to replace your existing receiver, or keep it as a backup. Nobody sells a "transmit only" Class B AIS.

If you are connected to your radio and MFD via NMEA2K you can probably leave the existing receiver in place and tell the displays to ignore it, although that will require a separate antenna.

If you are connected via NMEA0183 you'll have to disable the existing receiver. In a simple system there is not (usually) a way to have two NMEA0183 talkers saying the same thing because the sentences don't come with a source ID.
__________________

billknny is offline   Reply With Quote
Old 01-11-2019, 10:29   #3
Registered User

Join Date: Sep 2013
Location: Windham NH
Boat: Bristol 29.9 1978
Posts: 105
Re: AIS Transmitter Suggestions

It wouldn't be a big deal to remove the existing AIS receiver - and it wasn't a big investment. I am using NEMA2000 communications and receiving on the standard VHF antenna, a basic Shakespeare job. Any recommendations on a good AIS transceiver?
Homer Shannon is offline   Reply With Quote
Old 01-11-2019, 11:24   #4
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 8,407
Re: AIS Transmitter Suggestions

Are you looking for AIS-B or B+? I like Vesper Marine because of the service they give on CF. They seem to monitor CF and join in when they are able to help out.
DeepFrz is offline   Reply With Quote
Old 01-11-2019, 11:37   #5
Registered User

Join Date: Sep 2013
Location: Windham NH
Boat: Bristol 29.9 1978
Posts: 105
Re: AIS Transmitter Suggestions

OK, I had to do a little reading to give you a good answer. I think for my needs a standard AIS-B would be sufficient. I don't move very fast (sailboat) and I don't normally travel in highly congested areas.
Homer Shannon is offline   Reply With Quote
Old 11-11-2019, 06:31   #6
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 419
Re: AIS Transmitter Suggestions

I suggest you look closely at em-trak. em-trak is the house brand of SRT Marine Systems. SRT is more or less the gold standard in AIS devices. They design the actual silocon chips used in AIS, and they are the original equipment manufacturer (OEM) for many products sold under private label brands.

The em-trak Class-B model B100 used to retail for about $550, but the price has recently been reduced. You can find this Class-B AIS tranceiver for under $350. It may be headed for end-of-life and replacement with a newer model, but it represents a best-buy at this moment. See:

https://us.binnacle.com/p10043/em-tr...duct_info.html
[No affiliation with this vendor]

There is a more recently introduced model, the B300, which sells for about $480.

https://www.milltechmarine.com/em-tr...der_p_423.html
[No affiliation with the vendor]

At one time I was trying to keep abreast of Class-B transponders, and I wrote and updated an article on them. The article is a bit out of date now, but it may be useful for you. See

AIS Class B Transceiver Round Up
continuousWave: Whaler: Reference: AIS Class-B Transceiver Round Up

If you do get a Class-B transceiver (or transponder), I suggest using a dedicated antenna for it, rather than using an automatic antenna switching device to share an antenna. The AIS frequencies are at the very high end of the VHF Marine Band at 162-MHz. Most ship station antennas are tuned for the very low end of the band at 156-MHz, where all ship transmitters operate, and their VSWR bandwidth is usually not very broad.

AIS transmitters often will object to operating into a transmission line with a VSWR above about 2:1, and may not work very well trying to feed an antenna tuned for the wrong end of the band.

Also, the transmission interval of Class-B is rather infrequent, and it would be a shame to miss an opportunity to transmit when scheduled due to the shared antenna being in use by the other transmitter. The whole point of AIS is to transmit your position, and impeding that by sharing an antenna seems to be at odds with the point of having an AIS transmitter. A Class-B transmitter is just operating at a few Watts of power. You ought to provide the transmitter with a low-loss, low-VSWR transmission line to a well-tuned antenna.

The better antenna sharing automatic switching devices cost more than a second antenna will cost. They also add complexity to the system. Adding a second antenna for AIS will add redundancy to the system; you could is the AIS antenna for the voice transmitter in an emergency.

For those reasons, I suggest having a dedicated AIS antenna that is tuned specifically for 162-MHz.

If you must use a shared antenna, it would be best to replace the current antenna with a new antenna that is designed to have a wide VSWR bandwidth and is useful on both voice and AIS. Those antennas usually are made with larger diameter radiating elements to produce a broader VSWR bandwidth. Of course, they cost more than single-purpose antennas. Again, the dedicated AIS antenna seems like a good choice.
continuouswave is offline   Reply With Quote
Old 11-11-2019, 06:52   #7
Registered User

Join Date: May 2013
Location: Mangareva, French Polynesia
Boat: Heritage West Indies 36
Posts: 692
Re: AIS Transmitter Suggestions

We did what you want to do recently - indonesia required it - and it didn't require any messing around with the existing setup.

We bought a matsutec standalone AIS transponder from aliexpress for something like $350. You program it yourself with your MMSI (very, very easy. US or EU retailers won't let you do this. They want to program it for you before delivery I believe) and connect it to an antenna either via a splitter or a second antenna (we went with a second, deck-mounted antenna. That way if we lose our mast it can double as a backup).

Having two receivers running at the same time isn't an issue. Your existing setup stays the same and the Matsutec displays on it's own screen. Your existing unit should recognise the signal from the transponder as 'self' (because both units are programmed with the same MMSI no.) automatically and require no action on your part.
DefinitelyMe is offline   Reply With Quote
Old 11-11-2019, 07:05   #8
Registered User
 
Nicholson58's Avatar

Join Date: Jan 2011
Location: Caribbean live aboard
Boat: Camper & Nicholson58 Ketch - ROXY Traverse City, Michigan No.668283
Posts: 4,628
Images: 84
Re: AIS Transmitter Suggestions

Given that your current set up works and you like it I would add a second totally independent backup. We really like our Watchmate 850. It uses less than 10 watts and also performs as an excellent anchor watch. It can be networked but we leave it independent. On the hook, everything else is off and the Watchmate alarms if we exit the circle. Nearly all cruising boats in the Caribbean operate class B

Our VHS is also an AIS. Having a backup is nice. We consider AIS essential, second only to depth.
Nicholson58 is offline   Reply With Quote
Old 12-11-2019, 01:16   #9
Registered User

Join Date: Nov 2019
Location: Vancouver
Boat: Ericson 27
Posts: 3
Re: AIS Transmitter Suggestions

I installed a Vesper Marine XB-8000, and have been quite happy with it. We navigate using iNavX on our iPad, and this unit (combined with an NMEA multiplexer) puts all our data onto our iPads via Wifi.
hjohnson is offline   Reply With Quote
Old 13-11-2019, 12:21   #10
Registered User

Join Date: Dec 2018
Posts: 2
Re: AIS Transmitter Suggestions

Thanks for helpful comment - I am looking for installation of the AIS unit myself and I was considering various producers, but most of them are really expensive with no apparent advantages. Therefore I may be going with Em-Trak.
I would agree with the installation of the separate antennas for many reasons, but at the same time - do you have any suggestions as where this antenna should be installed (I would like to have it on the mast) to not to interfere with VHF antenna?
mjadczyk is offline   Reply With Quote
Old 14-11-2019, 20:32   #11
Registered User

Join Date: May 2013
Location: Mangareva, French Polynesia
Boat: Heritage West Indies 36
Posts: 692
Re: AIS Transmitter Suggestions

Quote:
Originally Posted by mjadczyk View Post
I would agree with the installation of the separate antennas for many reasons, but at the same time - do you have any suggestions as where this antenna should be installed (I would like to have it on the mast) to not to interfere with VHF antenna?
People often put a second antenna on a spreader, inboard near the mast. We put ours on the aft rail and it works well enough.
DefinitelyMe is offline   Reply With Quote
Old 15-11-2019, 00:00   #12
Registered User

Join Date: Mar 2018
Location: New Zealand
Boat: 50í Bavaria
Posts: 1,342
Re: AIS Transmitter Suggestions

If you're going to install a second antenna, there's an argument that it would be best on a separate pole such that you could use it for your vhf in case of dismasting.
Tillsbury is offline   Reply With Quote
Old 15-11-2019, 03:12   #13
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 12,441
Images: 14
Re: AIS Transmitter Suggestions

Quote:
Originally Posted by mjadczyk View Post
Therefore I may be going with Em-Trak.
We installed the Em Tack B100 last weekend and fired it up. 10 minutes work adding the MMSI number and details (you are allowed to do your own in the UK) and it started to transmit without any problems, showing up on Vessel Finder later that day.

I really didn't want to drill more holes than necessary to run the external GPS antenna outside, so mounted it inside next to the chart table. Works perfectly and the AIS software shows a good signal as expected.

The VHF antenna is a high quality Shakespeare 5400 recommended by Nick (SV Jedi). This is mounted on a 2m pole on the stern with the cable routed through to the chart table and will reach the VHF, if the masthead antenna were to develop a fault. We used this previously with a RX only AIS and it gives a good range of about 7 miles, often more.

Please Recommend a Quality VHF Masthead Antenna

The Vesper series get good reviews on CF, but I don't need AIS wifi and the cheaper price £300 for Em Trak against £500 for the Vesper 6000 clinched the decision.

Pete
Pete7 is offline   Reply With Quote
Old 16-11-2019, 15:22   #14
Registered User

Join Date: Apr 2011
Location: Northport, Michigan
Boat: Trailerable cruising boat
Posts: 419
Re: AIS Transmitter Suggestions

Quote:
Originally Posted by mjadczyk View Post
do you have any suggestions as where this antenna should be installed...to not to interfere with VHF antenna?
The best separation for two vertically polarized monopole antennas is to separate them vertically while keeping them in line, i.e., one above the other, but some distance between them.

More about mounting two antennas on a boat at

Mounting Two VHF Marine Band Antennas on a Small Boat - CONTINUOUSWAVE
__________________

continuouswave is offline   Reply With Quote
Reply

Tags
ais

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
AIS, Receiver or Transmitter fishsail18 Marine Electronics 291 19-09-2016 05:12
Why is an AIS transmitter so much more expensive than a receiver? David Dennis Marine Electronics 36 26-06-2014 10:14
AIS Transmitter Only Parisnice Marine Electronics 4 03-05-2014 11:38

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 17:42.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×

ShowCase vBulletin Plugins by Drive Thru Online, Inc.