| Occupies
part of the 13cm amateur radio band 2400-2450 Mhz with aTV assigned to: 2406-2424 Mhz for aTV1 & 2430-2448 Mhz for aTV2 2.4 Ghz Services in Mhz - Video - Audio - Data and Telephone devices share this band. As do microwave ovens (for cooking / heating water) Typical distance of most communication gear is ~10 meters to 100 meters (300feet) more if using specially designed narrowcast antenna (dish like objects on poles...) |
||||||||
| Wireless Audio Services |
Security TV |
Wireless Video Services |
"Bluetooth" Headsets Cordless Phones |
IEEE 802.11b =DSSS 802.11g =OFDM |
Wireless Data Services |
Microwave Ovens Cooking Food Water |
||
| Audio Services |
Video Services |
18 Mhz Bandwidth |
2.402 - 2.480Ghz |
2.4Ghz Data.Ch. |
5 Mhz Bandwidth |
50 Mhz Bandwidth |
||
| Phones Cordless |
. | . | Audio Channels |
-- | 2402 Mhz | . | ||
| Intercoms | . | . | Audio Channels |
-- | 2407 | . | ||
| wireless headsets |
. | . | Audio Channels |
01 | 2412 | . | ||
| wireless speakers |
2.4Ghz TV Ch.1 |
2413 Mhz | Audio Channels |
-- | ---- | . | ||
| "Bluetooth" | . | . | Audio Channels |
02 | 2417 Mhz | . | ||
| InfraRed extenders |
. | . | Audio Channels |
03 | 2422 | . | ||
| . | . | . | Audio Channels |
04 | 2427 | . | ||
| . | 2.4Ghz TV Ch.2 |
2432 Mhz | Audio Channels |
05 | 2432 | . | ||
| . | . | . | Audio Channels |
06 | 2437 | . | ||
| . | . | . | Audio Channels |
07 | 2442 | . | ||
| . | . | . | Audio Channels |
08 | 2447 | . | ||
|
|
2450 Mhz |
|
||||||
| . | 2.4Ghz TV Ch.3 |
2452 Mhz | Audio Channels |
09 | 2452 Mhz | . | ||
| . | . | . | Audio Channels |
10 | 2457 | . | ||
| Data Services |
. | . | Audio Channels |
11 | 2462 | . | ||
| Data Loggers |
. | . | Audio Channels |
12 | 2467 | . | ||
| WiFi Networks |
2.4Ghz TV Ch.4 |
2472 Mhz | Audio Channels |
13 | 2472 | . | ||
| . | . | . | Audio Channels |
-- | 2477 | . | ||
| . | . | . | Audio Channels |
-- | 2482 | . | ||
| . | . | . | Data Channel |
14 | 2484 | . | ||
| . | . | . | Out of band / guard band |
-- | 2487 - 2497 Mhz |
. | ||
| Terms: DSSS = Direct Sequence Spread Spectrum OFDM = Orthogonal Frequency Division Multplexing "Bluetooth" also uses this frequency, hoping many 1000's times a second. "Frequency Hoping" Allows more people to use this narrow part of the radio frequency spectrum by changing channels rapidly in predefined sequences. Thus allowing the "electronic smarts" to easily recover the audio / video / data information from what sounds like a hash of noise. Older video / audio systems show this noise as pulsating line interference or strong varying audio hiss. 2.4Ghz is considered a poor long distance (10's of km) terrestrial communication frequency due to the physics of water (vapor) absorption. As microwave ovens exploit this feature and operate at 1000's of watts inside a metal box to heat food. Because of this and an ever increasing list of devices using this band, Interference is very high. For short range with in 1 meter to 250 meters depending upon transmitted output power, interlinking devices is very good and with encoded signals turned on quite secure from other users of the frequencies / band. The other "public license" bands / frequencies that have similar uses for voice (phone) video (security) data (internet) are 900Mhz, 1.8Ghz, 5.8Ghz. Some of these bands are also used for mobile / cell phones, hence the ease of "bluetooth" or wireless functionality with your other communication / multi-media devices. |
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