many years ago, for an external transmission with a mobile unit transceivers are used equipments VHF, for which you had to install antennas, lead trained technicians, audio equipment and microphones, and perform complex operations, so that a transmission was successful and had an acceptable quality.
indiscriminate growth of radio systems that flooded the spectrum, and lack of control by the state, they remain virtually unused mobile VHF systems, the amount of interference that are recorded, and this added to the complexity of operation and the high costs meant that stations leave this mode.
In the last decade, with the advent of cellular telephony, there was a resurgence the use of mobile units in the radio, as the simplicity of communication, and low cost associated, led one journalist to a mobile phone and a recorder type reporter, was transformed into a complete mobile unit.
Everything would suggest that the emergence of new technology, practicality and prioritized cost saving on the quality of the broadcast.
Today when this technology is already mature, and not as new as before, and is open to any competitor, however small it may be, begin to materialize some concerns, which have always existed, but they seem to have been relegated to the background, and is related to the quality of these emissions.
In a national radio station, to some extent, with reasonable budgets, technology investment, this can become a competitive advantage, providing a differential characteristic, which can help to pull away from competitors.
The problem of poor audio quality in the airing of mobile chroniclers and the issuance of notes recorded, does not have a single, but multiple edges, so that must be analyzed by competition several factors that cause multiple drawbacks.
Recordings:
chroniclers made
shots with portable recorders such as "reporter" of analogue technology in magnetic cassette or microcassette. These devices, originally designed for domestic use, do not have technical characteristics that make them suitable for professional use, and among the most common problems presented by these devices can be highlighted:
- tape width and thickness, which greatly reduces the magnetizable surface, reducing the quality of the recording. Low
- recording speed that produces the same effect. Mechanisms
- low quality rubber belt transmissions, which produce instability recording speed, causing distortion and fluctuations in the audio. Built-in microphones
- poor quality and omnidirectional pickup that produce excessive noise detection environment, decreasing the quality and intelligibility of the audio.
- low signal-noise amplifiers, which is compounded by the blowing characteristic of the tape itself. Poor
- play built-in speaker to poor quality and very small dimensions, producing classic sound "pesky"
Poor
Cell phones:
Meanwhile
communications Mobile chroniclers, are performed with the use of cell phones, which were not designed for professional use in any of its forms TDMA, CDMA or GSM. These teams designed for personal mobile communications, technical characteristics that make it unfit for use, which are given to them in the station, and among them we highlight: Low
- bandwidth of the system degrades audio quality. Little
- power mobile equipment under the regulations related to radiation, and antennas with very low yields in terms of size reduction equipment.
- Poor network coverage that causes signal loss and momentary interruptions of the communication.
- packet loss and variation in the arrival time of packets, an effect called jitter, which results in degradation of voice tremor or fluctuation, and disruption of the words. Lock
- tape recorders when the phone is emitting, the influence of magnetic field on the head when it comes to the phone. Poor
- playback recorder, speaker of small size and poor quality, which is aggravated by poor transfer the microphone of the phone, again incorporating ambient noise emission. Low
- battery life
Status
The combination of these factors, or the existence of many of them contribute to the final result of mobile communications and reproduction columnists recorded notes into the air, are of very poor quality and do not possess the minimum requirements of what is considered as a communication professional features.
The first comment that deserves this, is motivated by the need to reduce operating costs, and a criterion that I think is wrong, broadcasters have chosen to use equipment and household systems, which are not suitable for professional use, and were designed for a very different application that is being given.
The equipment used in broadcasting, you must meet certain conditions of quality, reliability and availability, which is only found in professional-use systems from reputable manufacturers. Obviously
equipment of this type has a higher cost than domestic use.
the other hand we must clarify that when analyzing a problem, it is essential to address the solution holistically, and analyzed as a complete and integrated system. It is useless to solve the problem isolated parts, because in the process chain of a complex system, the weakest link is the one that will determine the final quality.
For example, no point in this case, improving the quality of the recordings, using digital technology equipment, as do many, if not jointly face the problem of cellular and otherwise, it would become a bottleneck, or as we said earlier, the weakest link in the chain, and the final quality of the system, would be as low as the quality of it, even when the audio jacks have been very good.
Proposed Solutions:
The market for international broadcast providers, offers solutions for each of the issues, which as I said should be considered as an integrated system, considering solutions for each of its parts. For recordings
then proposed acquisition of portable professional digital recorders.
These teams have multi-media real-time compression. At least recorded in Linear PCM (uncompressed) and ISO MPEG Layer II is the standard compression format of the international broadcast industry, but is common to also support other formats.
In some cases, a special non-destructive audio editor, which operates in the same compression formats that record, and allow you to perform basic functions like cut, copy and paste, with an easy and friendly, so you can be operated by non-specialists.
have a minimum capacity of 512 MB flash memory, which can store approximately 6 hours of recording high-quality MPEG Layer II. Many computers are equipped with removable memory type in any of the standard formats of the market.
also feature a USB port connection for transfer files to a PC, which gives them compatibility with most automation systems used in radio and TV.
All teams have a high quality microphone built in, but also some of which can connect an external microphone balanced professional use. This provides the possibility that the reporter used a microphone external steering, which allows you to shoot better quality, preventing the uptake of ambient noise.
They have a monitoring system with built-in speaker and some come equipped with a headphone jack and line input.
systems generally have one-touch recording and in some cases are also equipped with VOR (automatic start voice detection)
As for power, most work with standard or rechargeable batteries and also have the ability to be powered by an external source. Even with normal cells, under low power consumption, these devices achieve many hours of battery life.
....................... .... Marantz PMD 660 ................. AEQ PAW-120
During the NAB 2006 show we were watching some equipment of this type, under brands such as Denon and Marantz (USA), Sony (Japan) and AEQ (Spain) with similar benefits and costs of $ s 600 .- FOB so.
As far as the replacement of traditional cellular communications, there are solutions for professional use, and for this we use the portable audio codec. Usually these teams, with the incorporation of additional modules are able to provide the information in different ways, such as analog phone lines, ISDN digital lines (ISDN) or GSM cellular modules incorporated.
These teams able to extend the bandwidth of the communication standard, by encoding the audio to be transmitted and later decoding at the time of receipt.
usually have built-in mixer two or three microphone inputs and other line, which makes them a suitable equipment for fixed single drives, as commentary positions or in mobile environments as reporters or reporters on the move.
are generally very easy to operate and can be used by non-technical staff, making them particularly versatile and flexible.
If we analyze, come equipped with a module additional built-in cell phone that is compatible with any GSM provider, having the possibility to operate anywhere in the world, with the sole addition of a local provider's SIM chip, or in the form of roaming as a visitor out of your system home.
The coding delay is very short (about 100 ms) allowing two-way conversation without interruption, and coding algorithms used to get answers frequencies of 7 kHz on bit rates as low as 9600 kbps.
The encoding used, error correction and improvements on the modem help overcome the problems of bandwidth (bandwidth) and the limitations of the cellular network.
faster recovery from errors, avoids the stutter effect that normally occurs with cell phones, and also helps to overcome the problems of packet loss the effect of jitter.
These systems have greater stability, due to increased transmission power available (about 2 watts) and which are not restricted by the regulations of radiation, and also generally have an external antenna which further enhances the connection network.
come equipped with high-powered batteries, nickel metal hybrid (NiMH) which gives them autonomy 4 to 7 hours of continuous operation, depending on the conditions of use and the proximity of the cells. In places where access to electricity, have external regulated power sources.
This category also were looking at the NAB 2006 show, a very interesting Comrex brand (market leader in codecs phone) and the English AEQ showed a prototype of a highly versatile team, but size a little bulky, they think the market launch in October.
In the first case, Comrex system is composed of one side of a portable codec called Matrix a cost of u $ s 3.700 .- to which we must add the GSM module with a cost u $ s 850 .- and the other, one rack for receiving at the station at a cost of u $ s 3.200 .- All prices are FOB. Note that the unit is a single rack and is used to recepcionar several portable computers.
AEQ If the manufacturer would not disclose the price of launching a new product, which as stated is expected in October.
Eduardo Daniel Esarey
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