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Goudurix 30-08-2013 01:42

Raymarine AIS 250
 
Had trouble for 2 years with RayM AIS 250. Losing reception after 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? :banghead:
(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

Goudurix 03-09-2013 04:10

Re: Raymarine AIS 250
 
Com'on guys! :whistling:
Tell me! :confused:

goboatingnow 03-09-2013 04:14

Quote:

Originally Posted by Goudurix (Post 1329893)
Com'on guys! :whistling:
Tell me! :confused:

Yes there's a possibility that damage could be caused to the rf input stages.

Dave

scoobert 03-09-2013 05:25

Re: Raymarine AIS 250
 
so you didn't follow directions, and your having issues, do we have to put this in text for you?

Goudurix 03-09-2013 06:14

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! :D

Goudurix 09-09-2013 06:38

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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