Marine Radios

[renpirate]

I'm thinking about getting a hand held marine radio to take with me when I go diving. I was thinking about the Icom - IC-M88 Handheld VHF Radio Submersible and placing it in another water proof container to protect it from depth.

I am curious to get the input of other divers on their views of this safety precaution and whether their is a better radio.

 

[Don Burke]

I'm thinking about getting a hand held marine radio to take with me when I go diving. I was thinking about the Icom - IC-M88 Handheld VHF Radio Submersible and placing it in another water proof container to protect it from depth.

I am curious to get the input of other divers on their views of this safety precaution and whether their is a better radio.

When they hear you on the radio, how do they know where to look for you?

 

[renpirate]

When they hear you on the radio, how do they know where to look for you?

Situation #1 Left by dive boat

Call the boat to return to the last location. I would use a strobe and whistle to signal then. If calling the coast guard, they can use the radio signal to hone in on the general location.

Situation #2 Diving from shore, in distress

Tell whomever I get a hold of the general dive location and to send help.

 

[Don Burke]

Situation #1 Left by dive boat

Call the boat to return to the last location. I would use a strobe and whistle to signal then. If calling the coast guard, they can use the radio signal to hone in on the general location.

You might want to check on the range of a handheld radio at the surface of the water. You will be surprised how short it is.

Situation #2 Diving from shore, in distress

Tell whomever I get a hold of the general dive location and to send help.

A cellphone would be far more effective for that.

 

[renpirate]

You might want to check on the range of a handheld radio at the surface of the water. You will be surprised how short it is.A cellphone would be far more effective for that.

Good point about the range. I will check into that one, but I'm thinking that it is still going to be a couple of miles.

I always keep a cell phone in the car, but I was imagining a situation where I was out in the water and needed help.
A cell phone is good, but I haven't seen any that are submersible and the coverage is real spotty along the north coast of California where I dive. I always keep a cell phone in the car, but I was imagining a situation where I was out in the water and needed help.

 

[Don Burke]

Good point about the range. I will check into that one, but I'm thinking that it is still going to be a couple of miles.

Based on what I have seen out on the water, you will be lucky to get two miles.

A cell phone would be good, but I haven't seen any that are submersible.

I have seen some, but they were pretty expensive.

and the coverage is real spotty along the north coast of California where I dive.

That may bode poorly for contacting anyone on VHF as well.

 

[miketsp]

Good point about the range. I will check into that one, but I'm thinking that it is still going to be a couple of miles.

There is a range calculator on
http://www.artscipub.com/simpleton/simp.range.html
use 5W 150MHz and you will see that you are not even on the scale. At 6" antenna height your range will be negligable.

Antenna height is fundamental.

You really need to get your antenna to at least 9ft high by means of telescopic sections or sections of plastic tube that you can plug together. These sections could be bungied together to your cylinder when not in use. But you need to get a portable VHF unit that would allow use of an external plug-in antenna. A stainless steel VHF whip antenna with 10-12ft coaxial cable is easily obtainable. The big problem is to water protect the plug.

 

[Charlie99]

When they hear you on the radio, how do they know where to look for you?

You simply tell them what direction to go to come pick you up.

Look at the various incident reports. In virtually all cases, the divers could see the boat, but not vice versa.

The other advantage is that when the boat gets called on the radio, they know it is the time to do the sort of intensive, detailed visual search that is impractical to continuously carry out during the entire time that the divers are in the water. (A less benign description would be "it's time to stop daydreaming and to take a look around".)

At short ranges, audible signals also have the advantage of alerting an inobservant boat crew. The world's best visual signalling equipment isn't useful if nobody is looking.

 

[miketsp]

I was thinking a little more about the antenna business.
Probably the best solution would be a flexible antenna supported by a 9ft sausage.
Something like:
http://cap-es.airsmc.com/projects/antenna.html

 

[Don Burke]

You simply tell them what direction to go to come pick you up.

Look at the various incident reports. In virtually all cases, the divers could see the boat, but not vice versa.

The other advantage is that when the boat gets called on the radio, they know it is the time to do the sort of intensive, detailed visual search that is impractical to continuously carry out during the entire time that the divers are in the water. (A less benign description would be "it's time to stop daydreaming and to take a look around".)

At short ranges, audible signals also have the advantage of alerting an inobservant boat crew. The world's best visual signalling equipment isn't useful if nobody is looking.

It sounds like a loud whistle and a mirror would be a better solution to that problem. A couple of aerial flares and dye markers would be helpful too.