Icom M92D DSC Handheld

[Dockhead]

Originally Posted by colemj

That is what a personal AIS-SART is for.

Mark

I realize that, but DSC VHF radio is better in several respects, in my opinion. First of all, DSC messages are more robust and more likely to get through than AIS messages, and to go further. Second, a DSC distress message sets off a piercing alarm on all vessels which receive it. Third, a DSC VHF radio provides two-way communication. Lastly, a DSC VHF radio fulfills other purposes, like ordinary short-range comms.

Therefore, I would much rather have a compact DSC VHF radio on my person, than an AIS-SART, if someone would produce such a thing.

I do have a PLB in my life jacket, but that won't help much for an immediate MOB recovery since the signal is not received on board. Also, I only have one of them.

I also have a 121.5mhz MOB beacon -- two transmitters, and one directional locator. The transmitters go around your neck and go off automatically if they hit water. I bought them from a person back from a multi-year cruise; they are somewhat dated and probably need battery replacements. I have not yet put them into service. They must have cost a fortune -- I reckon thousands -- when they were new.

Better than any of this would be a simple, $200, very compact DSC VHF radio, in my opinion.

[transmitterdan]

Defender is selling the HX851 for $212.79 plus shipping. Until Dec. 31 there is a $30 rebate from SH. So now this radio is less than $200 including shipping. Maybe Santa will get me one...

[Auspicious]

Originally Posted by Dockhead

I realize that, but DSC VHF radio is better in several respects, in my opinion. First of all, DSC messages are more robust and more likely to get through than AIS messages, and to go further.

How do you figure that? DSC is on marine VHF channel 70. AIS is on marine channels 87B and 88B. Same sorts of data streams from the same radios in the same locations. How can DSC be more robust than AIS?

Originally Posted by Dockhead

Second, a DSC distress message sets off a piercing alarm on all vessels which receive it.

True.

Originally Posted by Dockhead

Third, a DSC VHF radio provides two-way communication.

True.

Originally Posted by Dockhead

Lastly, a DSC VHF radio fulfills other purposes, like ordinary short-range comms.

True.

On the other hand AIS/PLB-SART radios go off when they hit the water.

I don't think there is a clear winner, and there is certainly a limit to how much 'stuff' we can strap on while on watch. Choices.

Don't fall off the boat.

[transmitterdan]

Originally Posted by Auspicious

How do you figure that? DSC is on marine VHF channel 70. AIS is on marine channels 87B and 88B. Same sorts of data streams from the same radios in the same locations. How can DSC be more robust than AIS?

There are many more DSC receivers than AIS at this time. DSC MOB alert continues automatically until someone answers the call. Power output on DSC can be higher than AIS B.

Originally Posted by Auspicious

Don't fall off the boat.

+100%

[colemj]

I presume anyone who purchases an AIS-SART already has an AIS receiver on board. That's the whole point of having a personal recovery system on a boat, after all.

Mark

[a64pilot]

FWIW 121.5 is no longer monitored, yes of course it can be DF'd if someone knows to look.

[SVNeko]

An update on the HX851: Beware, after a year's use, the battery now lasts less than 3 hours on standby. It won't get through an entire watch. So if, like me, you planned to use it as a device to be worn on night watches so a MOB can relay his coordinates back to the boat, the short battery life will leave you with a nagging worry. Apparently realizing they had a problem, SH now puts a longer-lived battery in the radio, but won't provide it to buyers of the weaker battery. They offered for me to ship mine back at my expense so they could "test" it, but doing that while on the go in Central America would be far too costly and troublesome. So if you planned to use it this way, be sure to get the better battery. For me, I will use my ICOM M92D, which lasts much longer, or a less bulky, non-GPS handheld and hope the MOB can see the boat's lights.

[galacticair]

Originally Posted by SVNeko

An update on the HX851: Beware, after a year's use, the battery now lasts less than 3 hours on standby. (...) Apparently realizing they had a problem, SH now puts a longer-lived battery in the radio, but won't provide it to buyers of the weaker battery. (...) So if you planned to use it this way, be sure to get the better battery.

Thanks for the info SVNeko. How to tell which battery is which? I just bought the HX851 and would be great to figure out which I have...

[SVNeko]

They have different product numbers. Not sure what they are but a little googling will get you there.

[a64pilot]

If someone finds out will they post the answer?

[transmitterdan]

The standard battery that comes with HX851 is FNB-121LI. It is a 1380mAH 7.4V LI battery. I don't know if that is different than the early HX851 units they shipped.

Defender sells this pack for $34 plus ground shipping. Ground only because it is LI. Defender also sells the alkaline tray FBA-38 for $20 plus shipping.

[SVNeko]

FNB V99LI is the old one.

[a64pilot]

So assuming I go internet shopping, how will I know it I'm getting the old or the new battery?

[transmitterdan]

Originally Posted by a64pilot

So assuming I go internet shopping, how will I know it I'm getting the old or the new battery?

Just received new HX851 from Defender and it came with the 1380mAh battery. Charged it yesterday until full (about 4 hours). Has been running in scan mode with intermittent reception of weather forecasts for 12 hours. No indication of battery low level yet.

I suspect unless you are shopping on used sites or grey market you will get the latest battery.

[colemj]

That is interesting battery data. We have had our HX851 for two years and the battery hasn't lost any capacity as far as I can tell. We don't use it as a main radio or keep it on standby for long periods - it gets used every few days for a hour or so. I think it has only been on the charger 3-4 times total over the past 2 years and it has never shown the low battery icon. However, we are not using it like you do.

Hopefully ours doesn't follow yours into early battery death.

Mark