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Would a two way handheld like the one Sportys make be good enough? Or am I missing something?
It seems if the Sporty's Handheld worked good enough to listen on the ground, then you could also use it in the plane when your coms hit the crapper.
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A handheld transceiver similar to the models that Sporty's advertises would work great in the event of 2-way radio failure. It is also awesome for listening on the ground. However, for SCANNING, you kind of need a scanner.
A scanner has a set number of channels, each of which can have a specific frequency assigned to it (i.e. 121.9 in Ch. 1, 119.1 in Ch. 2, 135.3 in Ch. 3, etc). The scanner then "listens" to each frequency for a fraction of a second, and stops on a channel if it detects a transmission being made. Many models even delay the continuation of the scan after a transmission to ensure that the listener can hear the return transmission.
Most models in production now (stay away from Radio Shack...with a few exceptions, they're wayyyy overpriced) even allow you to name your channels (BNA GND, APPCH EAST, BNA CLNC, etc). This way, you even know who you're listening to without having to memorize all of the freqs.
These features really come in handy at a major airport. For example, at BNA when it's busy, there is a tower freq, clearance, ground, anywhere from 3-5 aprooach/departure freqs, etc, etc, etc. Then, of course, center, ATIS-D, ATIS-A, the list goes on and on sometimes. It's nice not to have to enter any frequencies when it's time to listen to airplanes (or Police officers, EMS, etc.).
Hope this rant helps...