1.SRD and ENERGY METER READING Applications .
It is important to have a clear knowledge of what a 'SRD' can do and what it can not do.
For relevant information about SRD please check www.ero.dk at link RECOMMENDATIONS on the reccomendation 'REC 70-3' annex.
The general philosophy is to allow application transmitting free (license free) on some frequency bands but with some relevant limitations:

·The frequencies are not protected by authorities.
·Limitations on radiated power.
·Limitations on duty/cycle of transmission.
·Integral antennas ( it means that external big antennas are completely forbidden).

The Idea is to permit a wide use of 'SRD' units and applications but to necessary the area of deployment and operation must be strictly 'short'. In this area there would be huge probability the useful signals is stronger than the interfering signals coming from other users.
It is also of paramount importance that:

·The radio receiver must be able to detect useful signal ignoring interfering signals as soon they are at least 10-15 dBm weaker (co-channel detection) and also to attenuate signals in the same band but on a different frequency (selectivity).

·The communic

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