I love the Futaba 6J but...

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I love the Futaba 6J but...

Postby s vernon » Sun Aug 25, 2013 3:44 pm

Three of us were sailing our EC-12s from the lee shore of the big lake in wind that topped out at about 20. Very choppy. There were two collsions while sailing upwind, both involving one of the boats. Not WHAM, but just minor hits, sort of a side by side hit and then stbd/port masts hitting in the second incident. In both cases that same boat lost radio contact. The thing that restored control of sails and rudder was turning the 6J radio off and back on. That was pretty much the only thing we could do standing on shore and watching the boat sail itself across the lake. Thank goodness.

That boat has the receiver velcroed fairly high on the hull side. (I have been working on the skipper to move it to under the deck.) The boat did not have problems at any other time during the couple of hours out there. Very little water in the boat.

There must have been something other than demons and devine intervention at work. Any ideas?
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Re: I love the Futaba 6J but...

Postby Fred Maurer » Sun Aug 25, 2013 7:46 pm

Just a note on receiver placement: I Velcro the receiver to the underside of the deck and the antennas are taped to the underside of the deck at or near the center of the deck. Two good things happen. One if not both antennas are always above water level and can "see" the transmitter. Two, they stay dry.
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Re: I love the Futaba 6J but...

Postby hedderick » Sun Aug 25, 2013 9:39 pm

Was the boat using an NiMh battery? If so, a very possible cause would be a brief period of "low voltage". The RMG winch and rudder demands in high winds can cause system voltage to drop when using an NiMh battery. This will then cause the receiver to momentarilly shut down and lose touch with the transmitter.Can happen with any radio.
Solution: Switch to LiFe batteries in the boat. They can deliver the high power demands without volatge drop.
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Re: I love the Futaba 6J but...

Postby s vernon » Sun Aug 25, 2013 10:42 pm

That boat would have gone into RMG battery limiter/failsafe mode and still would have been operable if the battery voltage dropped. That did actually happen early in the day, before the collisions. (Not my boat, but I had been working on it during the week and did not think to charge the boat battery.)
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Re: I love the Futaba 6J but...

Postby hedderick » Mon Aug 26, 2013 11:48 am

With a very momentary voltage drop, the RMG winch may or may not go into failsafe.
The RMG winch requires a brief 15+ amp power surge everytime it starts to move. Most NiMh batteries can only put out 1 amp, so the voltage drops very briefly. This can cause the receiver to drop out.
Using LiFe batteries has eliminated many "radio problems". The better LiFe batteries can put out 20 Amps continuous. There is lots of info referenced in the Life battery section under electronics. :lol:
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Re: I love the Futaba 6J but...

Postby s vernon » Mon Aug 26, 2013 1:45 pm

Richard,

It seems to me what you are talking about - temporary low voltage - would be the same as if you just turned off the boat switch (no power to the receiver so boat goes dead) and then flipped it back on. In that case the receiver and the boat would come back to life.

In our case the boat/receiver went down and stayed down until the radio was cycled off and on. And then the boat came back to life.
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