I installed class B AIS in Hong Kong specifically to be "seen" by commercial shipping.? Just prior to departure, when cruising from Aberdeen Typhoon Shelter up to Clearwater Bay to meet a sister-ship,?we discovered that neither of us could "see" the other on AIS until we were approximately 1 mile apart.? Further discussion with the electronics tech in HK suggests that the transmit power was quite low -- approx .5watt.? Spec (for the COMAR CSB200 Class B AIS Transponder) is 1 - 4 watt transmit, which should be sufficient.? Other than the sister-ship real-life check, I had one other opportunity to get a check on our transponder, when arriving off Dutch Harbor in the Aleutians the harbormaster reported they couldn't pick up our AIS signal off their?antenna which is quite high, and should've seen us as we approached from the NW coming around Cape Cheerful.? Following some changes to the NMEA data wires in Dutch Harbor, we had no further AIS transmit or receive for the rest of the voyage.? As the boat gets put back together, I'll have further opportunity to explore this issue.? This may be an issue of my particular installation, but I'd be interested in hearing if anyone else is experiencing insufficient?power to make the AIS useful for the intended purpose. Dave Nagle M/V?DavidEllis,? Diesel Duck 462-02 Seattle

You can test your transmitter using the marine traffic link below. Zoom into the city where you want to see the AIS traffic and see if you are sending and seeing a signal. You need to have Internet capability obviously. I found that this site works great in many locations but not all so it can be spotty. I routinely check my receive status. Regards, John Coyle M/V Seabright http://www.marinetraffic.com/ais/default.aspx?centerx=30&centery=25&zoom=2&level1=140 On Fri, Sep 11, 2009 at 1:08 AM, <dnagle1949@aol.com> wrote: > I installed class B AIS in Hong Kong specifically to be "seen" by > commercial shipping.? Just prior to departure, when cruising from Aberdeen > Typhoon Shelter up to Clearwater Bay to meet a sister-ship,?we discovered > that neither of us could "see" the other on AIS until we were approximately > 1 mile apart.? Further discussion with the electronics tech in HK suggests > that the transmit power was quite low -- approx .5watt.? Spec (for the COMAR > CSB200 Class B AIS Transponder) is 1 - 4 watt transmit, which should be > sufficient.? Other than the sister-ship real-life check, I had one other > opportunity to get a check on our transponder, when arriving off Dutch > Harbor in the Aleutians the harbormaster reported they couldn't pick up our > AIS signal off their?antenna which is quite high, and should've seen us as > we approached from the NW coming around Cape Cheerful.? > > > > Following some changes to the NMEA data wires in Dutch Harbor, we had no > further AIS transmit or receive for the rest of the voyage.? As the boat > gets put back together, I'll have further opportunity to explore this > issue.? This may be an issue of my particular installation, but I'd be > interested in hearing if anyone else is experiencing insufficient?power to > make the AIS useful for the intended purpose. > > > > Dave Nagle > > M/V?DavidEllis,? Diesel Duck 462-02 > > Seattle > _______________________________________________ > http://lists.samurai.com/mailman/listinfo/passagemaking-under-power > > To unsubscribe send email to > passagemaking-under-power-request@lists.samurai.com with the word > UNSUBSCRIBE and nothing else in the subject or body of the message. > > Passagemaking Under Power and PUP are trademarks of Water World > Productions, formerly known as Trawler World Productions.