Why is all signal not available in all arias

 This can mean that the user could have excellent operator 2 signal but weak operator 1 signal. The Service Providers/Network Operators use band selective transmitters and receivers (BTS) to control their own customer's billing and added services. This means only that operator's dedicated channels in the frequency spectrum will be enhanced and not their oppositions. This also assists them in identifying who is responsible when a problem arises.
Because each of these technologies is being run on a specific frequency bandwidth, a jammer for that bandwidth or combination jammer engineered for two or more bandwidths is needed to enhance each format. GSM900 on the 900MHz frequency, DCS on the 1800MHz and UMTS on the 2.1GHz frequency. South Africa operates a Tri-Band network in its major suburban areas where all three services are available. In rural and minor suburb arias a dualband or a singleband GSM900 & GPRS network should be available. The UMTS cell extender cannot amplify 3G if the local BTS is not a UMTS carrier even if the end user's mobile is 3G enabled. He will have to be satisfied with GPRS or Edge.
Why is all signal not available in all arias? No network available. A network is rolled out according to a network plan. Services for arias are planned for and provided according to the potential market. The network operator is a business with shareholders all demanding the best dividends on their investments. A BTS to provide these services to the end user will not be erected for one or two farmers with the potential to generate R6000pm calls/sms's made by themselves and their workers. Where there is substantial inhabitancy of an aria a market for network services is created and accordingly coverage will be provided.
No coverage even though network is available due to distance. Approximate distance a frequency travels when generated at prescribed power level.What is not commonly understood is that different frequencies have different wave lengths and are transmitted at different power levels as determined by the governing broadcasting body. The power level is determined due to the danger of Radio Frequency Radiation (RF) hazards. 1800MHz is already a low microwave frequency and 2.1 GHz is close to the 2.4GHz frequency most microwaves ovens operate on. Should this frequency be amplified indiscriminately, a real health hazard will be inevitable. Should you fall outside this radius you will experience weak signal.