Marine VHF feature
From KayakWiki
There are a number of features available for Marine VHF radio handhelds that you should consider.
Most handhelds on the market have the same basic set of features.
| USA, Canada and International channel assignments selectable. | Channels are different in each region. This lets you set all channels to the appropriate region in a single step. See Marine frequencies |
| Weather channels (WX) | See Marine frequencies (bottom of page) for information on WX channels |
| NOAA Weather alert | Operable in USA only |
| Multiple power settings | Most have two (1w and 5w) and some have a third (typically 2.5w or 3w). |
| Battery indicator | Lets you know roughly how much power is left. |
| Run time | Expect at least 8 hours. The better units can give 12-14 hours with the most powerful batteries giving 18 hours. Normal usage for this time is 5:5:90 Tx:Rx:Standby. That is 5% of the time is transmission, 5% receive and 90% standby. This may also be shown as 1:1:18. Note that this is on 5w output. At lower power settings, time can be longer. |
| Channel 16/9 quick select | Lets you switch to the call channels in a single button press. |
| Dual or triple scan | The radio automatically scans for traffic on two (or three) preselected channels. |
| Preset channel selection | This allows you to preselect the channels you most frequently use. |
| LDC and Button backlighting. | Useful for night use. |
| Key lock. | Prevent accidental button presses. This does not lock out PTT, power setting and a couple of other buttons. |
What really differentiates the various brands and models is the extra features - waterproofness, battery choices and special add-ons.
[edit] Waterproof
Look for a minimum of JIS-7 waterproofness. That means that it can be submerged for 30 minutes at a depth of one meter. It will handle the occasional dunking and can be safely rinsed to remove any salt water. It's a good idea to get a waterproof bag for it anyway. These are made by companies like Cascade Designs (Seal Line), Voyageur and Aquapac. The radio bags include a place to hold the antenna.
[edit] Battery choices
There are three battery types commonly available.
- Nickel Cadmium (NiCd)
Old technology and reliable. These batteries are best used frequently and heavily. However, kayakers tend to use VHF infrequently and other battery technologies are better suited. - Nickel Metal Hydride (NiMH)
Newer technology. These are well suited to kayakers, since the batteries can be discharged and recharged on an irregular basis without problem. The biggest drawback is that these batteries tend to self-discharge relatively quickly - about twice the rate of NiCd. As such, they tend to discharge even when not in use over a long trip. Note that they will hold about 60% of their power after a month on the shelf, so it isn't a drastic problem. - Lithium Ion (Li Ion)
These are the newest and most expensive technology. However, they have none of the disadvantages of the other types. They can be recharged on an irregular cycle without problem and do not self discharge at a rapid rate. They have the longest shelf life of the rechargeable batteries. These are the easiest to recommend if you want to go on a long trip and carry the VHF for emergencies. As well, it is the battery technology that is most reliable if you want to leave the radio on the shelf and then just grab it and go.
You can also look at special battery pack options for your VHF. Some manufacturers provide a AA battery tray option that will allow you to use any AA battery type. For example, you can get a NiCd standard and use NiMH AA or even Lithium AA (non-rechargeable) in a spare pack. Check the manual before buying - some will not allow you to use rechargeable batteries in a AA tray as they don't include overvoltage protection in the tray. In some of the tiny handhelds, the AA option only allows for low power operation. Larger units may or may not allow full 5w power - check before you buy.
Some also allow you to connect an external 12V power pack to recharge - you could carry a small AGM battery as a backup. As well, you can usually get a cigarette lighter adapter so you can recharge in the car.
[edit] Special Features
- DSC - Digital Selective Calling.
- This is a digital transmission protocol implemented on channel 70. It is available on a few high-end handhelds at this time. It allows for an automated distress call to be sent on marine VHF. See Electronic distress signal equipment for details.
- VHF/FRS Combination
- This is available in a few handhelds. By combining both VHF and FRS units into a single handset, it allows one kayaker in a pod to carry a VHF for communication with other boaters and allows the remaining kayakers to use FRS for inter-kayak communication. This allows kayakers who wish to to use cheaper, unlicensed FRS radios to chat amongst themselves and avoids the problem of one (or more) buying both a VHF and an FRS unit. Just watch for battery consumption.
- VHF/LMR Combination
- This is available in a few handhelds. Land Mobile Radio (LMR) is used for industrial radio communications on land. Useful for some commercial operators. LMR frequencies have separate licensing requirements.
- VHF/GPS Combination
- A couple of handhelds provide GPS capability in addition to conventional radio features. This can be useful in that it reduces the number of gadgets that you have to carry. However, it also means that you have to watch the battery consumption, as frequent use of a GPS can draw down a battery quickly.
- Remote Speaker/Microphone.
- Allows you to keep the radio on deck or inside your PFD and attach the small waterproof mic/speaker to your pfd.
- VOX Headset
- Voice activated headset. No need to press PTT (push to talk) - when you speak, the mic switches on the Tx. Advantage: hands free operation. Not sure if all headsets are completely waterproof.
- Barometer
- An option that you can add to some units. This widget allows you to track barometric pressure. Useful if you want to be your own weatherman. However, I'd recommend a separate weather meter if you really want to play weatherman.
- Voice Scrambler
- An option for the paranoid kayaker, though probably useful for commercial operators. Both you and your buddy have to have units with the same or a compatible voice scrambler.
- Distress Beacon
- A light that flashes SOS. It saves you having to carry a separate flasher. Since they seem to be LED based, a separate xenon flash based unit might be a better choice.
- Other Radio Frequencies
- AM/FM bands are available. Not bad if you want to listen to the ball game while kayaking. Aviation bands (receive only) are found on a few units.
