X-Band or AIS transponder ? - Page 4

Last Tango · 11 November 2018, 08:21

Just an update.....

I elected to fit a Matsutec hp 33A, seemed to have been around a while, good price, IPX56, very nice display and lots of features. With the huge variance in price I bought about "middle of the range" at £330 through Amazon from a UK supplier. (That was fortunate).

It's initial performance, fitted with a pukka 1mtr 161/162 AIS rail mounted aerial on the windscreen frame, was poor. When I change to a cheap (£26) VHF Aerial on the "A" frame the range trebled which was closer to what I was expecting.

Moving on two months it started playing up. Intermittently wouldn't power up....leave it for an hour try again and it would work. Similarly sometimes it wouldn't power off. I don't know for certain the cause but when we get that kind of problem with the medical equipment at work it's virtually always down to fluid ingress in the keypads.

A brief communication with Amazon, we were sent a "returns" shipping label and fully refunded by the vendor as soon as the parcel was posted despite being well beyond the thirty day return window. They didn't even wait to receive it so full marks to them.

I've now fitted an Icom MA-500TR. Cost nearly twice what I paid for the Matsutec, the display is not as good, it doesn't have all the nice features and worst of all it didn't fit the hole the other one came out of....perspex bezel made to suit. However it's IPX67, warrantied for three years and (initial tests) it's looking like it's performance is way better............here's hoping.

ShinyShoe · 11 November 2018, 13:11

Not sure ip56 on a rib is going to cut it...

Last Tango · 11 November 2018, 15:08

Quote:

Originally Posted by ShinyShoe

Not sure ip56 on a rib is going to cut it...

From my suspicion I'm thinking that's probably the case. However the definition of it's resilience is "high pressure jets of water from any direction". I've never had salt spray anywhere near the console instruments so the worst it's had to contend with is a bit of rain and even at that it was panel mounted and sheltered by the windscreen.
It was maybe nothing to do with water but as they say.....walks like duck... ?

ShinyShoe · 11 November 2018, 18:14

Yeah but if you look at the test spec, even for IPx7 it needs to survive 30mins immersion in water at a depth of 1m.

But it doesn't need to work immediately. It can be left to dry.

The test is with water, not salt water.

I wouldn't expect a piece of paper on the console to come off dry... But it will depend on consoles, boats and conditions...

Last Tango · 11 November 2018, 18:55

Quote:

Originally Posted by ShinyShoe

Yeah but if you look at the test spec, even for IPx7 it needs to survive 30mins immersion in water at a depth of 1m.

But it doesn't need to work immediately. It can be left to dry.

The test is with water, not salt water.

I wouldn't expect a piece of paper on the console to come off dry... But it will depend on consoles, boats and conditions...

I'm pretty confident IPx7 will do. If it's not properly sealed and water gets in it's not going to dry inside and corrosion on PCBs would pretty soon kill it. All the connectors are on the back of the unit and inside the console (as was the Matsutec.) so should be ok. Regards the salt water issue there is no sea spray at all ever hits the instruments on the console and to be honest I would expect the paper to come off more or less dry. Doesn't stop rain falling on it when the boat is stationary but IPx56 should deal with that.
My inclination is the manufacturer has not actually tested this at all. The unit is sold as a receiver only and is CE marked but the transceiver variant is not.

As I said it could be nothing to do with ingress but I was not going to buy another one the same. ;

gotchiguy · 14 November 2018, 13:12

Having had AIS for about 5 years now over the past couple of years there has been a big increase in the number of vessels fitting it, and indeed having it turned on.

I would now be pretty confident that most things over 10m will be transponding, and certainly most commercial boats although there continue to be reports of trawlers turning it off to avoid giving their favourite spots away to competitors.

Radar on the other hand does have the added factor of helping you be sure of your position - if the GPS fails you can cross reference coastal echoes to a chart without too much difficulty.

I don't think there's much point in fitting an rx only unit nowadays, the price different to a transponder has come down so much and you have to fit an antenna anyway.

Xk59D · 21 November 2018, 00:34

I've got this coming this week to replace my AIS receiver, looks decent on paper spec wise but time will tell.

Anyone got one per chance?

https://shop.marinetraffic.com/ais-t...0-class-b.html

Last Tango · 21 November 2018, 10:40

Regards our discussion about how the Class B AIS info finds it's way onto the internet........

https://www.marinetraffic.com/en/p/expand-coverage

Xk59D · 21 November 2018, 11:04

You called that correctly, nice.

So given I couldn't see part of your trip and it went to 30 min updates there is a coverage gap in that loch, probably both lochs actually? If the receiver is at KIP, as we speculated, that would maybe tie in as you were probably about 10 miles from KIP when you and breeze stopped updating.

Did you show up on it when you were testing it at home?

Next question is how class A gets on there in middle of an ocean.

willk · 21 November 2018, 13:27

Quote:

Originally Posted by Xk59D

Next question is how class A gets on there in middle of an ocean.

Satellite picks up the vhf AIS and downloads. All commercial based. Marine Traffic show the most basic data as a sales tool. Monkey see monkey want.

paulbrown22 · 21 November 2018, 13:36

Quote:

Originally Posted by Xk59D

You called that correctly, nice.

So given I couldn't see part of your trip and it went to 30 min updates there is a coverage gap in that loch, probably both lochs actually? If the receiver is at KIP, as we speculated, that would maybe tie in as you were probably about 10 miles from KIP when you and breeze stopped updating.

Did you show up on it when you were testing it at home?

Next question is how class A gets on there in middle of an ocean.

Satellite. I have a similar setup on our sailing yacht, only using mobile data - when within range of some form of 2G/3G/4G coverage, I can upload AIS positions for us and everything we are receiving.

The large commercial vessels do the same via their sat comms.

Xk59D · 21 November 2018, 14:15

Quote:

Originally Posted by paulbrown22

Satellite. I have a similar setup on our sailing yacht, only using mobile data - when within range of some form of 2G/3G/4G coverage, I can upload AIS positions for us and everything we are receiving.

The large commercial vessels do the same via their sat comms.

We had assumed/speculated it would have to be sat based comms.

So does your yacht have Class A I assume? Does it have SIM card in it or is it sent via on-board WiFi/234g setup?

paulbrown22 · 21 November 2018, 14:22

No, sadly only class B on our sailing yacht.

There are some more modern AIS units with direct upload ability (via built in cellular/wifi connections) , but I just have a standard (must be something like 8 years old now) DigitalYacht AIS transponder interfaced to both a computer and the onboard plotters/instruments, and if I can get some form of network to the computer (typically a cellular-based router with a 3 SIM in it), then I can upload the AIS data whenever I have a connection.

I have a similar setup at home, but a super cheap NASA class-B receiver with an aerial mounted on the chimney connected to a knackered old computer that sits in a cupboard transmitting over the wifi network.

Xk59D · 21 November 2018, 18:09

Thanks for info, all this came about because I was watching last tango and breezeblock vanish from one of the online AIS things up loch long. Their entire trip into loch goil wasn't there delaying getting the kettle on until they arrived back in range

paulbrown22 · 21 November 2018, 19:02

Yes, there can be a massive difference in the coverage of receiving stations for online services like MarineTraffic - because this is often random people sticking aerials in their houses/gardens and uploading the data, as opposed to some official Coastguard type arrangement, some receiving stations are much better than others.

It's certainly noticeable along the south coast, where some aerials are stuck on RNLI/Coastguard/NCI antennas at ~150m height, and others in personal property at maybe only a few metres high.

Personally I just use a standard marine VHF aerial mounted on the house, but some people design their own monster antennas that do seem to be quite an improvement.

AIS class B transmitters only use low power (2W) as well, so very easy to drop off MarineTraffic, especially if in an area of lower coverage, and on a RIB with a fairly low mounted aerial.

matata · 21 November 2018, 21:40

I've been following this thread and also considering an ais transponder or an x band. We sail as well as rib. mark one eye ball is obviously the best but if someone goes missing on the ais for 1/2 hour i'd be really worried if the visibility is poo. We are sailing around ireland next year and i'm looking for kit I can rely on in poo weather and i'm now having my doubt about ais. Specially if you can turn it off, typically if your fishing,there are loads of fishing vessels off the irish coast...thoughts?? Nik

Xk59D · 21 November 2018, 21:56

You wont go missing on AIS, you will maybe go missing on the online AIS sites, very different thing.

I don't know the regs for turning it off.

paulbrown22 · 21 November 2018, 22:27

Agreed - for it's "intended" usage of direct vessel to vessel reporting, at close range there should be no issue with AIS, assuming it's turned on. Range for vessel to vessel depends on the aerials/aerial heights of both vessels, and the transmitting power (class A or B), so might not be more than a couple of miles in a bad case.

Online AIS tracking is completely different to the "intended" usage, and yes, you can go "missing" if you go out of range of a receiver that is uploading it's data to the internet. That doesn't affect what your receiver on your boat will see though in it's receiving radius.

Obviously 1.) AIS is only compulsory fit for certain vessels, so not everything will have it fitted anyway, and 2.) There is a "silence" button on it which turns off the transmit feature, or the unit may go faulty. I've seen Navy and Border Force ships come and go on AIS, but who knows how many other vessels choose not to transmit for various reasons!

Personally I wouldn't be without an AIS transceiver on our sailing yacht - makes cross Channel and coastal passages so much easier, to be able to easily see most of the commercial traffic and much of the leisure traffic, and also know we are broadcasting our position to many others. We do also use radar and passive and active radar reflectors though if visibility is really that bad, to try and ensure nothing is missed.

At the end of the day, however much fancy kit you buy and install, agree with your original comment - a good lookout is vital!