Communication type
According to the type of communication, all modern walkie-talkies are divided into
analogue and
digital. Here is a detailed description of each option:
— Analogue communication. The simplest, from a technical point of view, way of working: the sound received by the walkie-talkie microphone is "embedded" into the radio signal directly, without converting to digital format. Accordingly, the main advantages of analogue radios are the simplicity of design and low cost. The key disadvantages of this option are the relatively low sound quality, which, moreover, strongly depends on the actual signal power: the weaker the signal, the worse the audibility and the higher the level of interference. In addition, the connection itself is not protected from eavesdropping: any user in the range of the walkie-talkie, having tuned in to your range and channel, will be able to hear your conversations. On the other hand, this can be both a disadvantage and an advantage — for example, if we are talking about a CB range car radio, often used to communicate with unfamiliar people. And you can protect the channel from listening, for example, using a scrambler.
— Digital communication. With this communication format, the analogue audio signal (electrical oscillations) is first converted to digital (a sequence of zeros and ones), and only then is sent to the transmitter. In the receiver, accordingly, everythin
...g happens the other way around: the digital-to-analogue converter restores the original sound from the stream of numbers. Digital walkie-talkies are noticeably more complicated and more expensive than analogue ones, but they have a number of advantages over them. First, the signal is much better protected from interference. Secondly, its quality does not change when the power changes: the receiving party either hears the sound in its original quality (even at the minimum signal level), or hears nothing at all. Thirdly, the digital format allows the use of various additional features, such as text messages. And fourthly, in such walkie-talkies it is much easier to implement eavesdropping protection. So, within the same range, hundreds or even thousands of channels can be provided, with random selection and periodic switching between them (a similar technology is used in mobile networks and Wi-Fi equipment). And interconnected devices can "agree" on a common unique encryption key — as a result, an outsider will not be able to decrypt digital data, even if he finds a communication channel.Number of channels
The number of channels on which the radio can operate. Each channel is essentially a fairly narrow subband within the main operating band (see "Frequency range"). The division into channels allows several groups of users to work simultaneously on the same territory and in the same range so as not to overlap on the air and not interfere with each other. The
more channels provided in the design of the walkie-talkie, the more likely it is to find a free channel and the better it is suitable for working in conditions of intense extraneous radio traffic. This is especially important for powerful "long-range" models. At the same time, simultaneous operation of several groups on one channel is also possible thanks to subcodes (see below).
Power source
— Ni-Cd. Nickel-cadmium batteries have strength, reliability, and resistance to low temperatures, which makes it possible to use walkie-talkies with such battery in cold weather. Also, Ni-Cd batteries tolerate high charging currents well, which significantly speeds up the process. Their main disadvantage is the so-called "memory effect": if the battery is started to charge without being completely discharged before, its capacity decreases. The original capacity can then be restored, but this requires certain tricks. In addition, Ni-Cd batteries are considered environmentally hazardous. As a result of all this, today they are very rare.
— Ni-Mh. Nickel-metal hydride batteries were developed as a replacement for nickel-cadmium batteries (see above), in order to eliminate their main disadvantages. Such batteries hold voltage well (it decreases only when the charge is almost completely exhausted), resistant to low temperatures, environmentally friendly and almost not affected by the "memory effect" - it only appears when stored in a partially charged state for more than a few days. As a result, Ni-Mh batteries have become quite widespread in walkie-talkies. Among their disadvantages, one can name a slightly shorter life cycle than that of Ni-Cd, a significantly longer charging time and unsuitability for storage in a discharged form.
— Li-Ion. Lithium-ion batteries are by far the most common type of batteries for portable electronics, including radios. They
...have good capacity with small size and weight, they charge quickly, and most importantly, they are not affected by the “memory effect”. At the same time, Li-Ion batteries are quite sensitive to low temperatures, and they are more expensive than "nickel" types (see above).
— Li-Pol. Lithium-polymer batteries are actually an improved version of lithium-ion batteries (see above) - with the same advantages, they have even more compact dimensions and lighter weight. However, the main drawback - sensitivity to cold - also remains, and the price may be even higher than that of Li-Ion. As a result, this type of battery is quite rare among walkie-talkies, mainly in premium models.
It is worth noting that among the walkie-talkies there are models with both built-in and replaceable batteries. In the latter case, the batteries can be the size of standard AA or AAA batteries. This allows, if necessary, to replace them with conventional disposable batteries or other batteries of the same size. Technically, you can even install batteries of a different type in such a walkie-talkie - for example, replace the complete nickel-metal hydride batteries with more advanced lithium-ion ones. However, if the kit comes with a charging stand (see below), you cannot use it for a "non-native" type of battery, because. different types of batteries have significantly different charging modes. In the above example, this will mean that only the bundled Ni-Mh batteries can be charged on the stand, and Li-Ion will require a separate charger.
— From the vehicle's electrical system. This type of power supply is used exclusively in stationary models (see "Type"). This option is convenient primarily because you do not have to monitor the condition of your radio's own batteries/accumulators: as long as there is voltage in the vehicle's electrical system, it will work. It is not even necessary for the engine to be running — the radio can be powered from the vehicle's battery (moreover, such devices consume relatively little power, and the batteries installed in modern vehicles are quite capacious). For this reason, stationary models usually do not have their own autonomous power sources at all.
