Comparison Kenwood TK-3107 vs Kenwood TK-2107

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.

The frequency range over which the walkie-talkie is capable of transmitting. This parameter is usually indicated if it does not completely match any of the standard radio operating ranges (see “Frequency Range”). For example, the transmission range is often specified for VHF and UHF models, as these bands themselves are quite wide, and individual walkie-talkies can only use a subset of these frequencies. The opposite option is also possible - wide-range models, whose specs go beyond the standards.

The frequency range in which the radio can receive transmissions. It is usually indicated if it does not coincide with one of the standard ranges of the radio; see "Transmission frequency range" for details.

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.

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").

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.

The type of antenna used in the radio.

— Non-removable. As the name implies, such an antenna is permanently attached to the body of the radio. Technically, it is most often possible to remove it, but for this you will need to disassemble the radio; replacement for such an antenna with another, of a different type, is not provided at all.

— Removable. The detachable antenna was originally designed to be quickly detached from the body of the radio, most often without the use of any tools. In addition to ease of transportation and storage, this design often provides the ability to change the stock antenna to a more powerful one, or even connect the walkie-talkie to a separate external antenna — to increase the range.

Note that the legislation of some countries refers the design of the antenna to the parameters that determine the conditions for licensing and registration: for example, walkie-talkies with removable antennas may be subject to licensing, while for completely similar models with non-removable antennas, it will not be required.

— Headset connection. The ability to connect a headset to the walkie-talkie — an earpiece (or headphones) with a microphone. The main purpose of the headset is to free your hands during a conversation. In addition, in noisy environments, an earpiece is often more convenient than an external speaker.

— Bluetooth. Medium-range wireless technology (10 to 100 m, depending on version) for direct communication between different devices. The main and almost the only way to use this technology in walkie-talkies is to connect wireless headsets that allow you to free your hands when talking. Bluetooth can be provided in both portable and fixed radios.

— Speech masking (scrambler). The presence of a speech masking feature in the radio: the built-in encryption module (scrambler) encodes the sound and broadcasts an encrypted signal, which is decrypted by the similar scrambler at the receiving end. The main purpose of this feature is to protect against unauthorized listening and interception of “sensitive” information: even if an outsider tunes the radio to the appropriate channel (or subchannel, see “Number of subcodes”), he will hear only a set of meaningless noises. For correct operation in this mode, the scrambler modules for all users must be identical. Also note that speech masking walkie-talkies may be subject to licensing in so...me countries.

— Voice activation (VOX). The ability to control the walkie-talkie with the help of voice: during the silence of the user, the device works for reception, and when the microphone captures the voice, it switches to transmission mode. Usually this feature is implemented through a headset (see above), which allows you to completely free your hands and makes the use of the walkie-talkie as convenient as possible: you do not have to press the button every time to switch to transmission mode. And to avoid accidental activation due to extraneous sounds, many models with VOX have a sensitivity control that allows you to set the volume level for triggering the switch.

— Volume control. The ability to adjust the volume of the speaker, which allows you to choose the optimal volume level depending on the environment. This feature is present in most modern walkie-talkies, with the exception of only the most inexpensive models.

— Auto noise reduction. The function of suppressing noise generated on the air by extraneous sources of interference, when the radio is receiving. Such noises create a signature hissing sound in the speakers (the same one that is heard when the radio is not tuned). It's useless "ethereal garbage", because when talking, it reduces the intelligibility of speech, and when silent, it wastes the battery charge to reproduce a meaningless hiss (which is also unpleasant to hear). The noise suppressor blocks these noises, thus increasing speech intelligibility and providing silence between phrases. Usually, walkie-talkies with this feature provide setting the level of noise suppression — for optimal separation of the useful signal and background noise.

— Channel autoscanning. The ability to operate the radio in automatic channel scanning mode (for more details on the latter, see "Number of channels"). In this mode, the walkie-talkie independently tunes in turn to each channel in search of a transmission signal. Channels without transmitters are skipped, and when a signal is detected, scanning is suspended — for a while or until a special user command. Thus, the user can listen to all active channels and select the desired one.

— Channel monitoring. The ability to operate the radio in the channel monitoring mode. In this mode, noise reduction is completely disabled (see above), and the user can listen to the unfiltered signal on each selected channel. This allows you to evaluate both the traffic load of the channel with calls and the overall level of interference, and select the optimal communication settings.

— Roger-Beep signal. The presence of an automatic end-of-transmission signal on the radio, the so-called Roger Beep. Such devices, when switching from transmit mode to receive mode, broadcast a special sound signal (usually in the form of a short squeak, hence the name), indicating the end of the transmission. This eliminates the need for the user to specify the change of modes himself (for example, with the traditional word "over") — his interlocutors will receive a signal about this automatically.

— Power saving mode. The walkie-talkie has a special mode designed to maximize power saving and allow you to extend the work without recharging the battery (or changing batteries). This feature is especially useful if you have to carry the radio with you for a long time, only occasionally getting in touch. Specific features in different models may vary: for example, some walkie-talkies in this mode are almost completely turned off, only periodically “waking up” and scanning the channel for activity; in others, specific power saving features can be selected as desired by the user.

— Vibration. The walkie-talkie has a vibrating call feature similar to that used in mobile phones: when a signal is received on the selected subchannel, the body of the walkie-talkie starts to vibrate. This feature can be useful in noisy environments where it is difficult to hear the sound signal from the speaker — or vice versa, in silence, when any extra noise is undesirable.

— Keypad lock. The ability to block the keys of the radio from accidental pressing. This allows you to carry the device in your pocket or tight case, without fear that due to an accidental movement, the settings will go wrong, the transmission will turn on, etc. The lock itself is usually controlled in a way that excludes as much as possible the possibility of its accidental release — for example, by simultaneously pressing two buttons.

— On/off button sound. The ability to turn on and off the beep that sounds when each button is pressed. An audible signal serves as a convenient confirmation of a full press; on the other hand, it may not be appropriate in some situations.

— GPS module. It implies the presence of a built-in module for receiving GPS data from satellites, which allow you to determine the exact location of the user. The accuracy of work largely depends on the number of satellites that see the receiver at a particular moment, and weather conditions, but, usually, it ranges from one to ten metres. The functions of the portable radio with built-in GPS may vary depending on the specific model. So, the device can simply display the exact position at the moment on the screen (latitude, longitude, altitude), as well as the direction and speed of movement. More advanced models with a large screen can show locations on a map or, for example, transmit the user's coordinates to the dispatcher.