Lately you’ve been experiencing some annoying problems in receiving TV channels, presumably due to an unstable and not particularly clean signal that reaches the input of your TV or decoder. Indeed, you have already carried out preliminary tests on the operation of the antenna, for example using the specific functions of your television, which have confirmed a certain discontinuity in the management of the signal within your system.
Overall, however, you have the feeling that the problem can be easily overcome with the integration of a simple antenna amplifier : an operation that you could carry out independently without having to call in a specialized technician. The only doubt that remains concerns how to adjust a TV antenna amplifier : therefore, before installing the one you have already purchased or buying a new one, you would like to be sure of the correct procedure to follow.
Well, you’ll be pleased to know that in many cases the addition of this particular device can be an excellent solution, capable of solving minor problems and enhancing any small signal deficiencies that often result in unpleasant interference. If you want to spend a few minutes of your precious time reading the following paragraphs, I happen to have some valuable advice to share with you on this specific topic. So, are you ready? Perfect, in that case I just have to wish you a good continuation!
How to adjust TV antenna amplifier
The first datum to consider in order to learn how to regulate a TV antenna amplifier is that relating to the average signal level , which, approximately, should be between a minimum value of 45 dBµV and a maximum of 70 dBµV for digital terrestrial and between 47-77 dBµV for the satellite one . In general, however, it is advisable to obtain an average value around 60 dBµV .
The best method to obtain this information is to use a special signal analyzer or field meter : on the market it is possible to find all types and for all budgets, but for occasional hobby use you can easily refer to an essential model which allows you to take note of the minimum and maximum peaks of the television signal recorded in a given period of time, of which, therefore, it will be necessary to subsequently produce an average .
To do this, just connect the main antenna output cable to the input of the device in question (obviously, I recommend that you perform this operation safely only if the antenna is easily accessible, otherwise I strongly recommend that you contact an expert of the sector) and connect the output cable to the remaining system.
Next, examine the indicators present on its interface, which must fall within the ranges indicated above: otherwise, in fact, both in the event of a defect and an excess, it will be necessary to proceed with the orientation of the antenna .
If you don’t have access to the antenna, try measuring at the first available entrance to your home, and estimate the length of the cable , thus considering an average loss of about 15-20 dB for a 50-metre extension . This value, however, is susceptible to important variations based on the quality of the copper and the shielding , the diameter and wear of the cabled section: it is, therefore, an approximate calculation useful for getting an idea of the current situation.
The signal, therefore, in addition to undergoing degradation especially in relation to the conditions of the coaxial cable which reaches the television from the antenna, is strongly conditioned by the complexity of the system and by the presence of other passive components such as dividers or shunts .
To obtain a plausible signal reception value, therefore, it is necessary to subtract the attenuation data from the previously performed measurement, which are usually given in the technical data sheets , sometimes also in the labels , of the passive elements mentioned above: if you obtain a result lower than the pre-established minimum threshold which I mentioned above, i.e. around 45/47 dBµV , in this case it is necessary to intervene with an amplifier .
As you probably already know, the latter is an active element that can be integrated into a system to increase the signal level and compensate for the losses encountered during its distribution. Naturally it will be appropriate to choose a product capable of covering the difference necessary to bring the signal quality back to the optimal range of values: unless there are special needs, usually a device capable of generating an increase in gain ( i.e. the increase of the input value) between 20 and 40 dB should be sufficient for the purpose.
If you have not yet bought it, I advise you to check, in addition to the aforementioned gain value, also other important parameters, such as the indication of the noise produced (since it is an active element made up of electronic circuits, it is natural that the latter produces noise, in some cases even significant), to make sure that the inputs are compatible with the type of antenna used and the relative frequencies and that there are a sufficient number of them with respect to your installation requirements.
Finally, consider that some models are self-powered , for example the external ones which must be placed directly on the antenna pole , while others require an external power source (typically the internal ones , which, however, must be positioned near the television) and that, therefore, you will also need to evaluate the availability of a power outlet near the point where you intend to place it.
Manual adjustment
Once you have determined how much signal loss you will have, you will have no difficulty performing the TV Antenna Amplifier Gain Adjustment . If you have opted for a device equipped with a manual control system , you will certainly have noticed the presence of a screw or a small knob associated with the available inputs, below which the band on which it operates is shown: this element serves precisely to control the incidence of the signal and modulate it in relation to the specific needs.
A device equipped with only one input with a maximum gain of 20 dB , therefore, will be able to produce an increase equal to the aforementioned value by turning the lever towards the [+] symbol with a screwdriver up to the maximum of its possibilities. However, turning it partially, for example halfway, will give an increase of 10 dB, a 1/4 of 5 dB and so on.
What happens, however, in the presence of amplifiers equipped with multiple inputs and corresponding adjustment screws? Well, in this case, to carry out the manual adjustment , consider that the maximum nominal value assigned to a specific band is divided among the connected systems : in a device with a capacity of 20 dB equipped with two inputs for the management of UHF frequencies (relative, therefore to the Digital Terrestrial signal) for example, to assign 10 dB to each of them it will be necessary to rotate the relative adjustment screws by 50% , while to assign respectively 5 dB and 15 dB it will be necessary to rotate the first one by 25% and the second one by 75 %.
It goes without saying that, if you have an amplifier with two outputs available but the signal loss occurs only on a television, it is possible to dedicate all the gain (or what is necessary) only to the latter by completely turning the respective screw and keeping the other inactive.
Automatic AGC function
Perhaps you are not aware of it, but some more advanced signal amplifiers have an interesting function, called AGC ( Automatic Gain Control ), which basically performs a continuous control of the input and output signal and autonomously adjusts the gain bringing it to the optimal values according to the needs.
This is a particularly suitable solution especially in those situations in which there are frequent signal fluctuations , for example in relation to the occurrence of intense climatic events , characterized by strong winds or torrential rains. In devices equipped with automatic AGC function , therefore, it is not necessary to carry out any intervention on the device following the correct connection of the device to the system.