Search results
Results from the WOW.Com Content Network
The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz [1] in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) [2] [3] and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia).
The 2 200 metre band is available for use in several countries, and the 2007 World Radiocommunication Conference (WRC-07) recommended it as a worldwide amateur allocation. Before the introduction of the 2 200 metre band in the U.K. in 1998, operation on the even lower frequency of 73 kHz, in the LF time signal band, was allowed from 1996–2003.
Particularly in the United States and at frequencies under 10 MHz, shortwave broadcasters may operate in between those bands, with the 60-meter band extending as high as 5.13 MHz, the 49-meter band down to 5.8 MHz, the 41-meter band as high as 7.78 MHz and the 31-meter band extending as low as 9.265 MHz.
Channel 36 (or 38 for LSB) became the unofficial SSB "calling channels" for stations seeking contacts, with the subsequent conversation moving to channels 37–40. CBers with AM-only radios are asked to not use channels 36 through 40. In return, SSB stations stay off the remaining 35 channels so they could be used by AM stations.
The 2-meter band is often used by ATV operators for coordination with each other via FM voice transmissions. Operators seeking an ATV contact might first attempt calling on a regionally recognized ATV liaison-frequency, commonly 144.34 MHz, then agree to an ATV frequency to use for the video transmissions.
Illustration of the spectrum of AM and SSB signals. The lower side band (LSB) spectrum is inverted compared to the baseband. As an example, a 2 kHz audio baseband signal modulated onto a 5 MHz carrier will produce a frequency of 5.002 MHz if upper side band (USB) is used or 4.998 MHz if LSB is used.
The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web.
In its most widely used form, APRS is transported over the AX.25 protocol using 1,200-bit/s Bell 202 AFSK on frequencies located within the 2-meter amateur band. Sample APRS VHF frequencies. 144.39 MHz : North America, Colombia, Chile, Indonesia, Malaysia, Singapore, Thailand; 144.575 MHz : New Zealand [10] [11] 144.64 MHz : China, [12] Taiwan