contalketech-blog

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ContalkeTech CTET-ZLINK4 3G4G POC radio DMR Mototrbo DMR radio Gateway

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4G LTE Tier II DMR Advanced Multi-mode Radio Headset With Body Camera NFC

Contalk CTET-99XS is a revolutionaly device in crossband industry. The first of its kind to offer an integrated solution to professional users, including law enforcement officers, security guards, airports and railways station staffs etc.

The radio supports multi-mode communication in different scenarios, whether it is daily routine patrols or emergency response, broadband or narrowband, utilising the public or private network.

3G/4G optional version

CTET-99XS have 3G WCDMA version and 4G LTE version for optional, which makes it have fast access to mobile network and support real-time data/photo/video transfer. It could be adapted to various push-to-talk(PTT) platform and all kinds of expanded functions of the platform could be performed on 99XS.

DMR/analog UHF mode

CTET-99XS is with built-in digital and analog UHF 400-470MHz frequency circuit. It contains 199 channels and with output power up to 3W. DMR/analog is an important supplyment when network weak or not covered.

Dual modes, dual standby, crossband communication in same group

99XS is a combination of wideband and narrowband, there is no conflict between modes. Instead, it is dual mode standby which means as long as in same group, it receive the signal from both POC radio user and DMR user, and when transmitting, all users could receive the signal

Body camera, pixel, night vision

Usually police officers or security staff take walkie talkie and body camera along at the same time. CTET-99XS could reduce the burden and increase convenience by integrating the body camera in the radio. 720p front camera and 1080p back camera, infrared night vision up to 8m, the whole evidence collecting could be done in 99XS and uploaded to center.

GPS_GLONESS_BEIDOU

GPS，Beidou and Glonass are optional on the radio for precise locationing, track playback, location sharing

NFC

Think about in routine guard patrol, a security guard need to take a two way radio and a patrol device at the same time which could be a burden. A two way radio with NFC function has been the first choice of clients in these areas

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What is ATEX Radio? What is Intrinsically Safe Radio and what are their difference?

Recently there are some clients come us for inquiring ATEX radio and Intrinsically Safe radio, here we introduce briefly about it.

Q: What is ATEX radio or Intrinsically Safe radio?

A: ATEX radio or Intrinsically Safe radio are usually used in environments that can be hazardous or volatile, in workplaces such as oil refineries, chemical processing plant, manufacturing facility, grain elevators etc. where dangerous can be caused by unintentional ignition of flammable gases, mists and vapours or by combustible dust etc. Normal radios used in these environments may cause severe consequences so taking safety as a priority, workers on these jobs need secure, reliable two way radios.

Intrinsically Safe radio means the radio is safe to use in hazardous environments where the presence of a potential spark, heat or flame could potentially create a safety hazard like in working site of oil rigs and refineries, gas mines, coal mines, chemical factories etc.

 Q: From the description I cannot tell the difference of an ATEX radio and IS radio, what’s their difference?

A: Intrinsically safe is low energy signaling technique that ensures the safe operation of electrical equipment in hazardous area by limiting the energy ( both electrical and thermal ) available for ignition.

The ATEX directives are mainly relevant for industry, environment or application that found to be at risk of explosion. So it mainly refer application in explosive atmosphere.

 Q: Is there international standards for ATEX radio and Intrinsically Safe radio?

Yes, in 2003 EU released directives to protect employees from risks in areas with an explosive atmosphere:

The ATEX 95 equipment directive 94/9/EC, Equipment and protective systems intended for use in potentially explosive atmospheres

The ATEX 137 workplace directive 99/92/EC, Minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres.

Though there are new ATEX directives in 2004, we noticed that the documents from our clients are still with requirements of 94/9/EC.

The standards include directives in different atmospheres with zone classification from Zone 0 to Zone 22 and corresponding frequency, equipment, equipment groups and category, area of application, level protections etc.

 As to Intrinsically Safe radio, usually clients require the products with Factory Mutual, TIA, or CQST certificates etc.

[contalketech-blog]

ContalkeTech launch the latest POC 4G LTE network to Motorola/Hytera DMR gateway

ContalkeTech launch a new device gateway CTET-ZLINK-4 as a complete solution to realize the communication among POC to DMR/analog with reliability and flexibility.

 CTET-ZLINK-4 use advanced analog to digital signal processing technology to transfer the POC signal to DMR, and vice versa. There are 4 ports, each to a different system, like port 1 with Motorola DMR in and port 4 with POC radio in, these two of the terminals as transfer medium, the communication of the Motorola DMR and POC radio are realized.

Since ContalkeTech release the gateway, we have already participated in various projects to assist police station, railway station, security guards etc. to connect their wideband system and narrowband system, realizing the communication among POC to DMR, POC to PDT, POC to Tetra system etc.

[contalketech-blog]

ContalkeTech IP67 Waterproof Walkie Talkie

When go for a kayakinh, sailing, fishing or any water-based movements, or working in heavy rain and terrible weathers, regular radios will not be able to work in these circumstances and what user need, is IP67 waterproof two way radio. Waterproof two way radio could not only withstand splashes water or falling droplets of radio, but also could also be submersed in water for certain time without losing their functionality. So waterproof two way radio is essential in some scenarios and ContalkeTech IP67 waterproof walkie talkie could provide various options to fulfill your needs.

 CTET-6710 is one of best selling waterproof radio this year due to its outstanding performance. It is with rugged robust shell for withstand any external forces as well as droplets or splash of water. And it is with 10W high power output for long range talk, which is rare in the market. The SOS function allow user to send emergency signal to outside if any accidents.

CTET-6703 is another model from ContalkeTech Co.,Ltd. Which is designed specifically for waterproof purpose. It could reach the standards of anti-immersion for 30 min and with speaker automative wave remover. For this model, 3W output and 5W output could be customized and multiple colors are available as well.

Well, in some countries, analog radios are no longer popular and digital radio is required in the same scenarios. ContalkeTech Co.,Ltd. is also dedicated to waterproof DMR projects and models like CTET-310, CTET-380 etc. have already passed the rigorous waterproof test of authoritative institutions.

If you are interested in the details or specs of these radios, pls. do not hesitate to contact with ContalkeTech for more information.

[contalketech-blog]

ContalkeTech Bluetooth Smart Walkie talkie CTET-GS88 Offgrid Digital Two Way Radio provide text, talk and offline maps to Android or IOS when no cell service or wifi

Bluetooth walkie talkie Mesh Network Digital Radio CTET-GS88 developed by ContalkeTech Co.,Ltd. is a revolutionary product which provides private and safe network to mobile phone in off-grid scenarios.

 CTET-GSGS88 works with a smartphone APP to provide a batch of service including audio communication(private talk, group talk, public broadcast), text messaging, GPS location mapping, SOS etc.

 2pcs or of bluetooth two way radio GS88, each connected with a smart phone via bluetooth,  could provide a private network with coverage of 4-5km in outdoor field.  The GS88 uses advanced technology and do not need to rely on cell towers, routers or satellites.

 Unlimited GS88 and smartphone could be added into the team to form a wide coverage net. Groups could be built flexibely and public broadcast could reach to all users. All the conversation are encryped.

 The downloading offline maps provide detailed GPS location in live-surrounding territories and buildings and you could easily find your friends.

 In outdoor field, it any accidents happen, the SOS function allow user to reach their team members in one second, and others could accept your signal and your GPS location.

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More details of how we test a walkie talkie microphone speaker in our factory!

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So maybe you wonder how a product like walkie talkie microhpone speaker to be tested in factory and how we could guarantee its quality. Here we explain how we test a single walkie talkie microphone speaker in our ContalkeTech factory!

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WiFi Walkie Talkie is a Push-to-Talk application which allows you to talk for free more wireless networks. You can broadcast your voice data to all devices which are on the same network or to any device which you know its IP address. http://www.contalketech.com/SOLUTION_lists.asp?BigClassName=Professional%20Walkie%20Talkie

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DMR trunking system from ContalkeTech

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ContalkeTech Walkie Talkie Bluetooth Headset Review

                                                                                           by Zack C

Walkie talkies are widely used in many industries, like in commercial, in transportation, in security patrol etc., where uninterrupted, undisturbed, and unobstructed communications are required. Though with many benefits, holding a walkie talkie in hand and press the PTT button every time may cause inconvenience sometimes when the situation that two hands are occupied. A regular headset will help sometimes, however, the twisted cables are troublesome and you still need to carry the walkie talkie on around!

 Well, Bluetooth headset for walkie talkie is getting more and more popular recently because of it really sets you hands free and there is no need to carry it around.

 This review is for CTET-BH88 walkie talkie Bluetooth headset from ContalkeTech Co.,Ltd. There are quite some advantages of it, but also have several points need to be improved.

The advantages of this ContalkeTech product is quite vivid:

 -The earpiece part of this ContalkeTech Bluetooth headset should be outsourced, I recognize it is a famous brand which considered as one of the best Bluetooth earpiece. This is very important, only use the best Bluetooth earpiece, the paring speed could be guaranteed and the voice remain same after through radio adaptor encoder. From my test result, the audio quality is remains perfect in both receiver and transmitter using this earpiece.

 -the universal compatible adaptor. This is also a key point when I purchase walkie talkie Bluetooth headset. Some of the product in the market only works for Motorola radio, some only works for Kenwood radio, this ContalkeTech BH88 could work on mostly analog radio, Motorola, Kenwood, Midland etc. But pay attention to choose the right connector!

 -The paring speed. It just take several seconds for the adaptor and earpiece get paired, and then you just need to press the PTT button to talk!

 -Transmit Distance. If you put the radio on the deck and move around wearing the earpiece and PTT ring, you will find the radio still work after you are 7-8 meters far from radio. This bring much conveniences if you donnot want carry radio on.

 However I don’t say this ContalkeTech BH88 is perfect. There are several points:

 -This Bluetooth headset seems not work quite well on some DMR radio. Certainly this need to be improved since DMR radio users are increasing.

 -The Bluetooth headset may be affected by surrounding electronic devices. If you intend to use it in a place where there are many electronic things, you need to pay attention, this Bluetooth headset may perform poorly there.

[contalketech-blog]

How DMR Radio work and ContalkeTech DMR Radio Review

ContalkeTech Co.,Ltd. has rich experience in radio area and DMR is one of focus of ContalkeTech Co.,Ltd. However, we noticed that though DMR radio have been widely used nowadays, there are still some users are confused that what is the difference of analog radio and DMR radio, what benefits the DMR radio may bring. Here ContalkeTech Co.,Ltd. would like to elaborate.

Not all DMR radios are same. There are three Tiers in the DMR standard: DMR Tier I unlicensed 446 MHz band, Tier II conventional radio system is 2-slot TDMA 12.5kHz wide peer-to-peer and repeater mode specification, resulting in spectrum efficiency of 6.25 kHz per channel, each time slot can be either voice or data depending upon system needs. and Tier III is trunked radios involving multiple repeaters at a single site. The most DMR radios in the market are Tier II radio.

DMR radio uses the 2-slot TDMA structure. What is the slotted structure? It provides the possibility of two calls on the same radio channel and permits units to receive signals even while user is talking. 

DMR Tier II occupies a 12.5kHz bandwidth that two channels share using Time-Division Multiple Access(TDMA). This results in spectrum efficiency of 6.25 kHz per channel. Comparing the spectrum efficiency of DMR to a wideband analog FM, DMR only uses 25% of the bandwidth per talk channel. Each channel can carry either voice and/or data depending on system design.

The current implementation of DMR utilizes the DSVI AMBE+2TM vocoder, some advantages of the vocoder include: very high voice quality and very low bit rate, robust to strong background noise and to PMR/LMR channel, moderate complexity etc.

There are many benefits of DMR radio comparing with analog radio, the most critical one is the audio quality. If you are using to operating on analog repeaters, you may notice that the audio quality degrades as a station’s signal into the repeater(uplink) gets weaker, it is the same situation on the receiver as the repeater’s signal gets weaker(downlink) as well. A combination of a station’s weak signal into a repeater and a repeater’s weak signal to the listener can make the usability degrade faster.

 On contrary, the basic difference with digital repeaters is that the audio quality remains the same on the uplink and downlink until the very end of the coverage range.

DMR has Forward Error Correction(FEC) which can correct small bit errors, slightly extending the usable range and improving communication quality.

Some users may worry about how to deal with their old analog radios after purchasing the DMR radio, there is no need to worry about this. Most DMR radios on the market have integrated analog mode so the radio could switch between DMR mode and Analog mode. The old analog radios could still be very useful.

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Factors affecting the working range of two way radios

One of the most frequently asked questions when people are in the market for two way radios is “ how far can they communicate?”  To the buyers or users, they expect the talking range of the two way radio reaches as far as possible. Therefore, knowing factors that determine the distance of a two way radio is of great help for users to choose the right walkie talkie.

First of all, a brief lesson on radio signal transmission is of essence to understand the whole range issue. Normally radio waves travel in a straight line from the transmitting antenna to the receiving antenna. However, like light waves, radio waves are affected by the phenomena of reflection, refraction, adsorption and scattering during transmission. The radio waves will become weak and the range that one radio receives the waves from another radio is so called working range of the two way radios. Now let’s analyze the main factors deciding how far the two way radios communicate.

Terrain, Geographic and conditions

During the propagation, the radio waves will be reflected to other directions if the obstacle is encountered occasionally. The obstacles include buildings, hills, atmosphere changes and etc. Radio wave decreasing, diffraction or refraction occurs when the wave passes through the edge of the buildings and hills. That means each travelling of radio waves will not be so smooth. The so-called working range of the two way radios is transmitting and receiving distance of the radio going through all the occasional obstacles. So the distance of the horizon is technically the maximum communication range for a two way radio.  

Two Way Radio Power

  Another important factor in determining how far a two way radio will communicate is its power output. The power output is measured in watts. Normal handheld two-way radio broadcasts between 0.5-5 watts. The amateur handheld two way radios run between 1-5 watts depending on the model. Current FRS/GMRS/PMR models broadcast at 0.5 watts with certain frequencies like CTET-Q40 from contalketech. 

The CB mobile radio may broadcast anywhere from 5 to 100 watts. However, the common power output of the vehicle mobile radios at market is 25W/45W. But the mobile transceiver CTET-AM970 and CTET-AM990 share the maximum power output at 65W. Moreover, two CB radios can be integrated to be as a repeater. In brief, the more watts a radio has, the farther it can transmit.   

 Typically, a 1-watt walkie-talkie with an average number of obstructions in its path yields about a mile of coverage. Range increases by approximately 30-50 percent if you double power. So, a 2-watt walkie-talkie might broadcast within a range of 1.5 miles; 3 watts = 2 miles; 4 watts = 2.5 miles; 5 watts = 3 miles

…12 watts=7 miles.

  Radio Frequencies 

One more factor in the range a two way radio will communicate is the frequency it uses and the environment that the frequency is used in.   

There are two major formats for most amateur two ways radios at the market. They are Ultra High Frequency (UHF) radio and Very High Frequency (VHF) radio. The most frequently used frequency ranges are UHF(400-512Mhz) and VHF(136-174Mhz). Both of the two radios are effective way to communicate with each other then choosing the right radio depends on the application.   

 UHF Radios work best for most two-way radio users due to the shorter waves and easily penetrating areas of interference in buildings, hilly areas and urban outdoor settings. UHF walkie talkies with a good-sized antenna and enough power will reach further into a building and push through steel, concrete and earth. If your two way radios are going to be used exclusively indoors or if they will need to be used both indoors and outdoors. UHF two way radio is your best choice.  

 The advantage of a VHF walkie talkie is that it can cover more distance with less power because VHF wave would travel almost twice as UHF radios. That makes VHF easier to transmit over a long range. VHF walkie talkies work best when there is clear line-of-straight between the sender and receiver with little obstacles. VHF radios are used exclusively in aviation and marine communications where the signals are sent across the sea level or between the sky and the earth. The VHF two way radios are also great for open fields, landscaping and for outdoor areas with few obstacles. Different antenna options are available for the VHF walkie talkie to use at the various settings.  

Below photographic might help you understand the difference of UHF radios and VHF radios more clearly.

  From the above factors, it is clear that the actual communication distances may vary widely based on the terrain, environment, weather, output power , UHF vs VHF, etc. Thus, we could choose the right radios as per our actual requirement. If you would like to use the radios at different places or situations and the long talking range is at your consideration as well, the UHF and VHF dual band with high power output like the dual band analog radio CTET-598 which enjoys 12W will turn to be your best solution.