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Old 30-08-2013, 02:42   #1
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Raymarine AIS 250

Had trouble for 2 years with RayM AIS 250. Losing reception after Ī 30 minutes warm-up, losing all signals on the plotter screen but the RM plotter still sees the AIS as present/active.

It has been in twice with Raymarine in the UK. The first time they reported "no problems" "it received about 20 targets in a 5 hour span" which did not convince me at all.... After functioning initially and receiving information (an be seen from a flickering red led) it stops receiving.

I now received a brand new AIS from Raymarine, even out of warranty! Thanks Raymarine!

However, I want to avoid getting the same problem for which I have 2 suspicions:

1) after initial installation using the masttop VHF antenna through the splitter in the AIS250, I remarked interference from the unit on the adjacent marine VHF frequencies in my old Icom 80H VHF. I then installed a dedicated AIS antenna on the pushpit. This received well enough, goen the interference, but it is on the opposite side of the SSB-sloping "alternative backstay" wire antenna, about 3 meters away.
=> MAYBE THIS BLOWED SOMETHING IN A RECEIVER STAGE OF THE AIS250?
(I now went back to using the splitter and masttop antenna)

2) the RayM installation manual states "installing the AIS250 blackbox minimum 2m away from an SSB transceiver and 1 m away from a marine VHF "to avoid EMC issues". Mine is only about 50cm (0.5m) away from those...
=> CAN THIS BE THE CAUSE OF PERMANENT DAMMAGE?

Glad to hear your opinion and eventual precaution advice. (did install large clamp-on ferrites at the AIS blackbox.

Jan
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Old 03-09-2013, 05:10   #2
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Re: Raymarine AIS 250

Com'on guys!
Tell me!
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Old 03-09-2013, 05:14   #3
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Com'on guys!
Tell me!
Yes there's a possibility that damage could be caused to the rf input stages.

Dave
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Old 03-09-2013, 06:25   #4
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Re: Raymarine AIS 250

so you didn't follow directions, and your having issues, do we have to put this in text for you?
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Old 03-09-2013, 07:14   #5
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Re: Raymarine AIS 250

Scoobert,

everything in yout boat is installed to the letter, especially with regard to avoiding EMC interference. Yes?

There is a differnece between EMC issues and a receiving stage blowing or being dammaged.

There is NOTHING in the installation manual about antenna distance, evenso the standalone AIS antenna was 3m away from the SSB antenna....

I find it hard to believe that the AIS receiver would be dammaged when it is 50 cm away from an Icom marine VHF and a HAM SSB transceiver, both operating at VSWR <1:1.5.

So I suspect more the previous antenna placement (now corrected back to using masttop VHF).

But I asked about both possible causes anyway.

Sorry for doing so!
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Old 09-09-2013, 07:38   #6
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Re: Raymarine AIS 250

Installed the replacement Raymarine AIS 250 (sorry Scoobert...exactly in the same location). It works OK.

I also did a receiving loss test receiving either directly via the masttop antenna to receiver (A) or (B) masttop antenna via AIS 250 splitter to receiver.

As receiver I used my FT897 as it has an S-meter.

As transceiver an Icom handheld VHF, set to low power, 2 km away, set in a fixed position and ensuring minimal operator interference when pushing the PTT to transmit.

On the (rather not calibated) S-meter there was clearly loss for (B) .:
S9 without the splitter (A)
S7 with splitter (B)

Well of course I would never rely on the FT897 LCD S-meter to relate it to dB's or microVolts, but there is a CLEAR loss! The Raymarine AIS manual does not state a loss in dB but "advises to use the VHF without the splitter for optimal performance.

Even if this test is far from standardised I do think that an S1 and S3 signal will make a difference in weak signal reception and I will definitely go back to a dedicated AIS reception antenna and VHF via masttop antenna.

I also wired the AIS and the Navtex receiver to a seperate swith breaker on the panel so I will be able to switch them off when wanting to transmit the SSB and avoid dammage to both receiver stages.

Jan
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