Re: 2-Way radios
Here is some 2-way radio information I have posted elsewhere:
Most of the license free radios are FRS (Family Radio Service) which is a low power (half a watt), 14 channel UHF service. Radios are inexpensive, some as low as $10 each, and the range is about a half a mile or so. The problem will be the number of groups using them. On a cruise with 2000+ people, a fair percentage will be relying on these radios. I would recommend getting a model that has sub-codes, CTCSS, "Interference Eliminator Codes" or whatever each manufacturer chooses to call this feature. Basically this feature uses a filter circuit to block transmissions from other radios not set to the same code (a sub audible tone). Most models with this feature have 38 codes to choose from. Advanced models have as many as 99 codes.
This feature does not eliminate all the traffic that shares 14 channels. Occasionally you will not be able to get through when others are transmitting on the same channel. What is does do is prevent strangers triggering your speaker every time they transmit. That might be every few minutes! By choosing a channel and sub-code combination for your group, the odds of being interrupted by others will be greatly reduced. When your friend/family calls using the correct, previously set code, only their voice will come through. When you wish to start a conversation on a channel, it is good manners (and legal policy) to check if the channel is free. Almost all radios have a "monitor" button that opens the receiver squelch to listen to the channel. If you hear static, the channel is free. If someone is talking, wait a minute and try again. If a particular channel is often busy, switch all your group's radios to another channel that is less popular.
Another type of radio is the GMRS (General Mobile Radio Service). GMRS is a higher powered UHF service that shares the 14 FRS channels and has 8 channels of its own. Range is greater (up to 5 miles) when using the GMRS channels. Altogether there are 22 channels in models that are both FRS & GMRS. The downside is that an FCC license is required (no test, just $75 to Uncle Sam) if you use the GMRS channels and/or higher power. One license is good for the entire family and all their radios, it is called a "system license" and is valid for 5 years. Also, these radios are a bit more expensive ($30 and up) and will eat batteries faster if you always use the higher power setting. The model chosen should also have the CTCSS/sub-codes feature. The most common models have both FRS and GMRS modes combined into one radio.
If you plan on using these radios everyday of the cruise you should consider getting rechargeable batteries (NiMH type with a charger). Most radios require four AAA type batteries and can burn through a set of alkaline batteries each day if you use them often. On a 7 day cruise you might need over 50 fresh batteries to keep 2 radios going.
Other features that are worth considering are: Vibrating call alert (good in noisy places), memory scan (nice if you need to monitor more than one channel) and weatherproof cases (if they might get wet).
Jim
