Hey, thanks for coming back to Wi Fi fundamentals location and analytics. This course will help you to muster the air. In part one of RF math we have learned DBS decibels, we have seen that they're used as a relative measure between two power units. They measure that change the difference. The next thing to do is to take a look at our Wi Fi network and find out where it is used and how. First the antenna which is the next topic that we will learn.
Antennas are all over in our stations and access point. There again, the way they focus the radio energy is calculated using DPS but it is DB in Relation to an insert tropic antenna. We will look at it in more detail in our next lesson, but remember, when you see an antenna again remember that the reference model that changing power is in relation to an optimal is a tropic antenna. DBS are also used to find out the relation between two devices that transmit. So, if we say that one access point transmits in 10 minutes that and the other transmits in 20 minutes, the power difference between the two access point is actually three dBm. Why, because as you will see very soon, three dBm is actually doubling that power.
Signal to noise ratio is another place where we see dp. We have mentioned Before it is a measure to compare the signal that our station or access point has received compared to the background noise that comes from other electrical devices. The outcome is the SNR. How do you calculate it very simple, you take the noise minus the signal and that is the SNR. Another good usage of DBS is when you want to find out the loss or to describe the loss in power from the access point to the station. So, if our access point transmits a signal in 10 milliwatts and our stations receives it as a five milliwatts signal, we say that the loss can be described as the minus three dBm loss.
Remember, three DB doubles the output power minus three DB represents a loss of 50% of your power you can find out the relation between DB and VAT in this table. But trust me, the principles are easy. We say that in a DB world there are actually two main rules, three DB rule and the 10 Db rule. A treaty B raise is doubling the power treaty B loss have the power 10 Db raise 10 times the power 10 Db loss 10 times less the power you can calculate just about anything using this rules. If one AP transmitting 10 millivolt and the other in 20 millivolts, which is double. We say that the transmit power is three is three DB stronger.
Remember three DB is double the power. The next rule I want you to remember is Very practical every time you wish to double the coverage of your access point, add six DB to its transmission power. The reasons are beyond this part of the course we will look at them later on. But remember this six DB doubles the coverage of your access point. Next up a whole new topic antenna. That's the place where radio waves propagates towards their destination.
See you soon