scope of telecom

scope of telecom lies but limited in radio spectrum i.e. 3 Hz to 3000 GHz (3 THz).

Print (text and image)
Radio (AM and FM; only audio)
TV (audio and video)



GSM works at the boundary of radio and microwave spectrum

380 MHz
450 MHz
850 MHz
900 MHz
1800 MHz
1900 MHz

!dea Cellular uses
GSM900 as 3G:  824 MHz to 960 MHz
GSM1800 as 2G: 1710 MHz to 2180 MHz



1 GHz - 2 GHz [L]: cell phones (2G, 3G and above), GPS

1176.45 MHz (10.23 MHz × 115) GPS, L5
1227.60 MHz (10.23 MHz × 120) GPS, L2
1575.42 MHz (10.23 MHz × 154) GPS, L1

lower frequencies allow carriers to provide coverage over a larger area, while higher frequencies allow carriers to provide service to more customers in a smaller area.


0 Hz: Direct Current
25 Hz: o/p freq. of 12 pole 250 RPM 2 phase generators @ the Niagara Falls, built by Westinghouse in 1895
50 Hz: hi-frequency alternating current (India, Europe)
60 Hz: hi-frequency alternating current (Brazil, US)
400 Hz: powering-up of aircraft, spacecraft, submarines, server rooms for computer power
24kHz: Induction Cookers; medium-frequency alternating current (20 – 100 kHz) flows.
32.768 kHz: i.e. 2^15 cycles per second ocillating freq. of quartz crystal in clocks
38 kHz: most common Infrared LED carrier frequency used in TV remotes (ranges from 30 kHz to 60 kHz)
315Mhz or 434Mhz: car keys using RF
500 kHz - 1.5 MHz: AM Radio (Amplitue Modulation)
1.023 MHz: GPS PRN codes are 10,230 bits long and transmitted at this freq.
10.23 MHz: fundamental frequency of highly precise oscillators in satellites
13.56 MHz: DMRC Metro Card NFC Frequency
50 MHz - 88 MHz: Tele-Vision
88 MHz - 108 MHz: FM Radio (Frequency Modulation)
175 MHz - 800 MHz: Tele-Vision
865 MHz - 867 MHz: RFID (India, US, Europe)

2.4 GHz: Bluetooth

Many different power frequencies were used in the 19th century. Very early isolated AC generating schemes used arbitrary frequencies based on convenience for steam engine, water turbine and electrical generator design. Frequencies between 16⅔ Hz and 133⅓ Hz were used on different systems. For example, the city of Coventry, England, in 1895 had a unique 87 Hz single-phase distribution system that was in use until 1906. The proliferation of frequencies grew out of the rapid development of electrical machines in the period 1880 through 1900. In the early incandescent lighting period, single-phase AC was common and typical generators were 8-pole machines operated at 2000 RPM, giving a frequency of 133 cycles per second.

Power frequencies as high as 400 Hz are used in aircraft, spacecraft, submarines, server rooms for computer power,[18] military equipment, and hand-held machine tools. Such high frequencies cannot be economically transmitted long distances; the increased frequency greatly increases series impedance due to the inductance of transmission lines, making power transmission difficult. Consequently, 400 Hz power systems are usually confined to a building or vehicle.
Transformers and motors for 400 Hz are much smaller and lighter than at 50 or 60 Hz, which is an advantage in aircraft and ships. A United States military standard MIL-STD-704 exists for aircraft use of 400 Hz power.

my Lenovo A6000+ has FM range from 87.50 MHz to 107.90 MHz

92.7 MHz: Big FM
93.5 MHz: Red FM Bajatey Raho