TV-SAT Instrumentation

How to choose a field meter?

The field meter is undoubtedly an essential tool of a telecommunications installer, as it is the tool capable of measuring terrestrial radio, television and satellite signals, guaranteeing that a satisfactory installation has been carried out.

In order to buy the ideal signal meter, we need to choose carefully. These are expensive devices and it is not advisable to buy one that will be too short in a few months, or to make a heavy investment in which we will not get even 10% of its performance.

Field Meters 

Type of Signals 

The 3 most common types of television installation are: terrestrial television (DTT and Radio), satellite television and cable television. Most meters perform measurements for all 3 types of signals, but in many cases it is only necessary to work with a field meter with functions for DTT and cable internet signals. The more signal types the meter interprets, the higher the price will be. Are you looking for a professional Field Meter  o an  economic field meter ?

If we do not want our field meter to become outdated, we can consider buying a meter that can be upgraded without having to go through the factory. Manufacturers are continually upgrading the software of their meters and adding new functions and features. Keeping the meter up to date allows you to keep the channel list up to date, both DTT and satellite, and also to carry out installations much more reliably. We highlight the Televes H30FLEX Field Meter H30FLEX.

The field meters that can be updated, allow measurements to be recorded and downloaded directly to the computer and issue reports, installation guides and test protocols for the radio television of common telecommunications infrastructures of a real estate complex.

Types of Field Meter Measurements 

Analogue measurements. We highlight the following:

- Power: This is the level of the analogue signal being received. It is measured in dBuV.

- C/N. It is the ratio between the signal power and the noise floor. It is usually measured in dBuV.

Digital measurements: Digital measurements vary depending on the type of signal we are measuring (DVB-T, DVB-C, DVB-S or DVB-S2). Below we highlight the digital measurements common to these 4 types of signals:

- Power: This indicates the level of the digital signal being received. It is normally measured in dBuV.

- CBer: This is the bit error rate measured before the Viterbi decoder (it is not corrected).

- Mer: This is the modulation error rate. It measures the quality of the modulated signal. It is one of the most commonly used error measures for digital measurements.

Also commonly used are measures such as VBER, Constellation or Link Margin, which are not common to all signal standards.

Many meters, such as  Promax  or Televes, display along with the measurements, an indicator that the measurements are correct, so that it is easier to interpret the sample signals. The standards indicate different measurement values depending on the point where the measurements are taken, so it is necessary to tell the field meter where we are. It is not the same to measure the signal at the head-end of a building or at the user's socket. Check the ICT2 regulations.

Field Meter Functions

The basic functions improve with the quality of the meter and its performance. They are:

Measurement function: Undoubtedly the most important function of the meter. It displays all the measurements necessary to check that the installation complies with current regulations.

Most high-end meters perform the same measurements, so we will have to analyse the sensitivity and the margin of each model.

Spectrum Analyser: This function will allow us to see the signal as a function of frequency and power, represented in a diagram. Span and reference levels are usually evaluated as the most important parameters.

Each meter may have a different scaling for the Span, so it is useful to know if we need to see the signals very "enlarged". It is important that the field meter has a spectrum analyser with a real time sweep speed, in order to be able to see the signal variations.

TV mode: This function is actually the least important of all. It is the one that allows us to see the image and listen to the audio of the signal we are measuring on the screen of the analyser. There are different modes: analogue, digital, standard definition and high definition.

If we really know how to interpret the measurements, it is not usually used, but in most cases it is very useful for our client to check that the signal received is correct and can be seen and heard in perfect conditions.

Tips for buying Field Meter

Please note that there are field meters with different span ranges. The cheapest ones are only able to show the signal in "Full Scan" mode or with a certain span. You could say that they only have one zoom mode.

As a tip, we recommend working in spectrum analyser mode with the reference level as high as possible. How is this done? It's simple, we should always have the signal with the highest power as high as possible without clipping it. This way the measurements will be as accurate as possible, as the noise floor will be as low as possible.

Another feature of the spectrum analyser mode is that it allows us to make measurements both per channel and per frequency. Depending on the nature of the signal, the channels will be expressed in one way or another. For example C57, which corresponds to a DTT channel in the UHF band with a centre frequency of 762 MHz and a bandwidth of 8 MHz.

A further indispensable function of the field strength meter from February 2024 is the display of the signals in high definition. After the SD DTT switch-off, the field meter must incorporate a DVB-T2 high-definition tuner. This tuner will allow us to see the high definition image on the screen of our spectrum analyser, but in no case does it imply that it performs specific averages of high definition signals such as Link Margin or BCH Ber.

Another of the most important features to consider when purchasing a field strength meter is the size of the display, the dimensions and the weight. The larger the display, the more comfortable it is to work with the field strength meter, and on the other hand, the larger the display, the heavier it is and the more difficult it is to transport.

Nowadays, meters are getting lighter and lighter thanks to the use of TFT and LED screens, limiting the dimensions to little more than the size of the screen.

Another very important parameter when purchasing a signal meter is the autonomy of the battery. The more autonomy the field meter has, the longer the battery will last and therefore the longer we will be able to use the meter without needing to recharge the batteries. It is therefore vital to know the autonomy of the meter, because if we are working all day long with the meter we must ensure that the batteries last as long as possible. In these cases it is also often interesting that the field meter incorporates an external 12 V DC adapter, so that it can be charged in the car when we travel from one job to another.