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.Frequency range
The frequency range supported by the radio for both reception and transmission.
—
CB (27 MHz). Abbreviation for "Citizens' Band" (sometimes spelled "Civil Band"), i.e. "civil range". One of the most widely used modern ranges, in particular in the CIS, in many countries CB radios do not require licensing. The technical features of the range are such that it is poorly suited for urban development, but provides good communication outside the city. As a result, such walkie-talkies are widely used in vehicles, especially among truck drivers — they allow you to exchange information at a distance of up to 5 km and warn other drivers about the traffic situation in advance. Also this range is used by many emergency services for direct reception of information.
—
LPD (433 MHz). An abbreviation for "Low Power Device", which fully describes the features of walkie-talkies for this range. They have low power consumption and often do not require special batteries (ordinary batteries will do). At the same time, due to the high frequency, LPD models behave well in urban conditions, with dense buildings and an abundance of other sources of electromagnetic interference — the communication range can reach 2-3 km. This range is used mainly in Europe and the CIS, in many countries models for it do not require licensing.
— PMR (446 MHz). Abbreviation for "Private Mobile Radio" — "private walkie-tal
...kie". This range is in many ways similar to LPD (see above): in particular, it is intended primarily for urban conditions, it is used mainly in Europe and the CIS, and walkie-talkies under PMR can be used without a license in many countries.
— FRS (462-467 MHz). It stands for "Family Radio Service", which is "walkie-talkie for family use." It is one of the varieties of the UHF band (see below), it has low power consumption on the one hand and relatively short range on the other. Generally refers to the "urban" bands, similar to LPD and PMR (see above), however, unlike them, it is used mainly in North and South America; in Europe and the CIS, such walkie-talkies require licensing at best, and in some countries they are generally prohibited for use.
— VHF. Abbreviation for "Very High Frequency" — "very high frequency", this range covers frequencies 134 – 174 MHz. VHF radios have good range and signal penetration, suitable for both urban and rough terrain, but such devices require a rather long antenna for reliable operation. As a result, VHF is widely used in professional radio communications, in particular maritime and taxi services, but in many countries such walkie-talkies can only be used after registration and/or obtaining a license.
— UHF. The "Ultra High Frequency" range is "super high frequency", most often this definition means frequencies of the order of 400 – 470 MHz. It is a kind of analogue of VHF: it is widely used in professional walkie-talkies and requires licensing in many countries. At the same time, UHF, due to its high frequency and short wavelength, has good penetration and does not require long antennas, which makes it more suitable for compact "city" type radios.
In addition to the above, it is worth noting two points regarding the licensing and registration of walkie-talkies of all ranges. Firstly, license-free conditions often describe not only the range, but also a number of other technical specs (primarily this concerns the power of the transmitter and the type of antenna, see more about both below). Secondly, in different countries (even within the same region), the legislation relating to radio communications can differ significantly — as a result, a model that is freely sold in one country may be subject to registration or even be banned from use in another. And for professional models, a license may be required not only for a walkie-talkie, but also for a specific frequency. Therefore, before purchasing a walkie-talkie, it makes sense to separately clarify the relevant provisions of the law.Walkie-talkie included
The number of walkie-talkies in the standard delivery set, usually
1 or
2. Pairs are most often supplied for beginners and/or non-professional users: by purchasing such a kit, you immediately get everything you need for two-way radio communication. Very rarely there are sets for 3 or more walkie-talkies.
Range
The maximum communication range that a walkie-talkie is capable of providing when used with the same model.
Speaking of range, note that usually its perfect value is indicated in the specs. And it is achieved only under a combination of certain conditions: the complete absence of obstacles (houses, trees, etc.) and interference in the passage of radio waves (for example, due to increased solar activity or the presence of powerful transmitters nearby), full battery charge, optimal air temperature , high-quality transceiver at the other end of the line, etc. In fact, the communication range, usually, is much lower. Therefore, when looking at this parameter, it is worth taking a certain margin.
Transmitter power
The maximum power at which the radio transmitter is capable of operating. This parameter is one of the most important: it determines both the range of the device (see above) and the features of its use and registration (for more details, see "Frequency range"). For most models of the "amateur" (conditionally) class, the power level does not exceed 2.5 watts. More powerful walkie-talkies are, usually, professional models of the VHF and UHF bands (for more details, see "Frequency range").
Power levels
Many modern walkie-talkies have
several power settings, most often two — low (Low) and high (High). The first option is useful if the the other walkie-talkie is at a short distance: the transmitter will not consume excessive power, respectively, the battery will last longer. If the distance is large, you may need the “High” mode, in fact, the full power of the transmitter.
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).
Active channels
Single-channel walkie-talkies work on receiving and transmitting in only one channel, two-channel ones have
2 active channels in their arsenal, between which you can switch instantly at the touch of a button. The option with two active channels is suitable for communicating with two users who are not in contact with each other on different frequencies. In advanced models of two-channel walkie-talkies, dual-reception technology is also implemented with automatic switching of broadcasting to the channel on which the transmission is taking place.
Number of subcodes
The number of subcodes provided in the design of the walkie-talkie. Subcodes are used to create separate subchannels with different coding within one channel (see "Number of channels"). This allows several groups of users to communicate simultaneously on the same frequency channel without interfering with each other. Thanks to the combination of channel and subcode, the number of subchannels available for communication can be in the hundreds — which is more than enough even in a busy air. In entry-level models with low power, the possibility of using subcodes may not be provided at all as practical uselessness — there are not too many users within their range. But for powerful radios with a long range, the presence of subcodes is very important.