Know the importance of choosing a Field Meter
The field meter is undoubtedly the essential tool of a telecommunications installer, since it is an instrument capable of measuring radio signals terrestrial and satellite television, and ensure that installation has been performed successfully.
To acquire a field strength meter, you must know what our needs, so we can hit with our purchase, as they are expensive equipment and is not wise to purchase a meter that we fall short of performance in a few months, or the otherwise invest heavily to that we will not get out even 10% of their benefits.
Therefore, to know that field meter suits our needs, we need to know how to interpret what measures we need to perform because there are essential measures that might not work (for example the power or MER) and others are used only in specific cases (eg the Ecos measures) and well as the type of signals with which we will work.
We need know about the signal kind that we are going to work. Normally it makes for DTT and Radio and Satellite one, also cable networks. A lot of Field Meters are for this kind of signals. . Muchos medidores realizan medidas para estos 3 tipos de señales, pero si por ejemplo trabajamos para un operador de cable, no sería necesario que nuestro medidor de campo realice medidas para televisión terrestre o satélite, y sería sólo necesario trabajar con un medidor campo con funciones para señales de TV e internet por cable. The more types of signal interprets the meter, the higher its price.
Functions of field meters
The majority of Field Meters do the same functions. These functions are improving, like:
Function Measurements: Undoubtedly the most important function of field strength meter. It will show all necessary measures to ensure that we are running the installation complies with current regulations.
There are different types of measures, depending on the signal that we are measuring (analog or digital) the field meter should represent the most important signal for each standard measures. Most high-end meters perform the same steps so we have to analyze the sensitivity and range of each model.
Spectrum analyzer: This feature allows us to see the signal represented in a diagram as a function of frequency and power. In the spectrum analyzer function is often value the Span and reference levels as the most important parameters.
Each meter can have a different scale for Span, so it is useful to know whether we need to look very "extended" signs. It is also important that the field meter has a spectrum analyzer with a scanning speed in real time, to see the signal variations.
TV mode: This feature is actually the least important of all. It is what allows us to see the image and hear the audio signal being measured on the meter display field. There are different modes: analogue, digital, standard definition and high definition.
Actually if we interpret the measurements, not often used, but in most cases comes in handy for our customer to check that the signal being received is correct and is seen and heard in perfect condition.
Once we know the basic functions performed by a field strength meter, you need to know what steps can make a gauge. Below are the most common measurements made by field meters and we give a brief explanation of each we indicate.
Analog measurements. We highlight the following:
- Power: The level of analog signal received. Typically it measured in dBuV.
- C / N. It is the relationship between signal strength and the noise floor. It is usually measured in dBuV.
Digital measurements: Digital measurements vary depending on the type of signal you're measuring (DVB-T, DVB-C, DVB-S or DVB-S2). Below we highlight the common digital measurements to these 4 types of signals:
- Power: It indicates the level of digital signal received. Typically it measured in dBuV.
- CBER: The bit error rate measurement before Viterbi decoder (not corrected).
- Mer: The modulation error rate. It measures the quality of the modulated signal, and is one of the measures of error used for digital measurements.
It is also often used measures such as VBER, Constellation or Link Margin, which are not common to all signal standards. Many meters as Televes or Promax, displayed along with an indicator measures if the measurements are correct, so it is easier to interpret signals yet that the meter shows. Just be careful to tell the meter field at which point of the installation we are making the measures, since the rules indicate different measurement values depending on the point where we make the measure. Not the same measure the signal at the output of the head of a building or making user.
If you decide to purchase a measuring field, we end up using in most cases the function analysis of spectra, since the experience we can get a lot of information signals, just watching the representation of these signal as a function of the received power and frequency.
In addition, all field meters displayed on the screen of the spectrum analyzer large number of measures, and the frequency or channel according to the standard that is representing. If you want to see in detail a signal at a particular frequency, we'll just increase the span of the spectrum analyzer. We can see the signals coming across the frequency band, which we call "Full Span" and gradually increase the signal span gradually up to only display the signal. Is the better gauge field this signal will see in real time.
Buy a field strength meter: what to consider
Mind you, there are field meters with different ranges Span. The cheapest are able to show only the signal "Full Scan" mode or set span. We could say that one has a zoom mode.
As a tip, we recommend working in spectrum analyzer mode with the highest level of reference possible. Is this how it's done? It's simple, we always have more power signal as high as possible without this cut. Thus the measures will be more accurate as possible, because the noise floor is placed as low as possible.
Another of the most common characteristics of field meters from different manufacturers, working in spectrum analyzer mode, which allows us to channel therefore measures such as frequently. Depending on the nature of the signal channels are expressed in a form or another. For example C57, which corresponds to a channel DTT UHF band with center frequency at 762 MHz and a bandwidth of 8 MHz.
Another of the most important features to consider when purchasing a meter field is the screen size, dimensions and weight. The larger screen is more comfortable is working with the field meter, however it tends to increase the size and weight thereof.
At present, they are getting ever lighter manufacture meters thanks to the use of TFT and LED, limiting the size by little more than fills the screen.
We also need to emphasize as important parameter when purchasing a meter field the battery life. The more autonomy is the field meter, the longer the battery will last us and therefore more time can be using the meter without recharging the batteries. Therefore it is vital to know the range of the meter, because if we are all day working with the meter must assure us that the batteries last as long as possible. In these cases usually also it assesses the field meter incorporated into external DC 12 V adapter for charging the field meter in the car when we move from one job to another.
The Field Meters that can be updated, allowing us to record measurements and dump them directly to your computer, to issue reports, newsletters installation and testing protocol for installing Radio Television of common telecommunications infrastructure set property.
We are sure that the meter field is the best investment you can make an installer of telecommunications, therefore we invite you to get in touch with us if you have any question before purchasing such equipment.
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