The radio frequency signals (RF):

RF is electromagnetic wave and used by communication systems for transfer data through the air from one point to another, knowing that RF was used for many years. It carries the music to radio and video up to television. In fact, RF is the most common ways to carry data across the wireless network.

Positives and negatives of RF:

We also discussed the comparison of the use of the light signals.

The positives of RF:

1. A relatively long area of up to 20 miles.
2. It works well in the weather conditions, Joe misty fog with the exception of heavy rain
3. The work of a free license (only for the systems rely on standard IEEE802.11). security is limited by radio propagation to a distance less than the service area

The negatives of RF:

1. The entry of data up to the field of MBPS.
2. It is highly subjected to the interferences of RF from external systems rely on RF.
3. Security is limited because of radio propagation to a distance less than the service area.

Barriers of RF:

RF signals face obstacles such as the proliferation and multi-track overlapping, and that affect on communications between the receiver and transmitter, causing a low performance in most cases.

Overlap:

Overlap occurs when two signals are in the station of the receiver in the same time, with the assumption that the phase and frequency are the same, which is similar to someone try to listen to two other people talking the same time. In this case, it is given (NIC) wireless network cards which receive errors when encoding the rest of transmitted data.

Federal Communications Commission (FCC) uses most of the frequency packages and types of amendments so as to avoid the possibility of overlap of the signals among systems.