![]() Much of this band was shared with broadcasters, and in most countries the bottom 100 kHz or 200 kHz are available to amateurs. Popular for DX at night, 40 metres is also reliable for medium distance (1,500 km 1,000 miles) contacts during the day. 40 metres – 7.0–7.3 MHz – Considered the most reliable all-season DX band.The allocation limits amateur stations to 15 watts effective isotropic radiated power (EIRP) however some locations will be permitted up to 25 W EIRP. The 2015 ITU World Radiocommunications Conference (WRC-15) approved a Worldwide Frequency Allocation of 5.351.5–5.366.5 MHz to the Amateur Service on a secondary basis. Voice operation is generally in upper sideband mode and in the USA it is mandatory. Five channels are available in the US, centered on 5.332, 5.348, 5.368, 5.373, and 5.405 MHz since most SSB radios display the (suppressed) carrier frequency, in USB mode the dial frequencies would all be 1.5 kHz lower. In most (but not all) countries, the allocation is channelized and may require special application. 60 metres – 5 MHz region – A relatively new allocation and originally only available in a small number of countries such as the United States, United Kingdom, Ireland, Norway, Denmark, and Iceland, but now continuing to expand.In the US and Canada the portion of the band from 3.6–4.0 MHz, permits use of single-sideband voice as well as amplitude modulation voice this sub-band is often referred to as "the 75 metre band". Only countries in the Americas and few others have access to all of this band, in other parts of the world amateurs are limited to the bottom 300 kHz (or less). Works best in winter due to atmospheric noise in summer. 80 metres or 80 / 75 meters – 3.5–4.0 MHz (3500–4000 kHz) – Best at night, with significant daytime signal absorption.See also: High frequency Most of the customary band names given below are only nominal wavelengths, not actual wavelengths for example, in the western hemisphere the nominal 80 m band actually ranges between about 85.7–74.9 m the nominal "17 m" band actually covers 16.6–16.5 m, and the so-called "15 m" band is actually from 14.28–13.98 m. International agreements assign amateur radio bands which differ by region. Some bands may not be available or may have restrictions on usage in certain countries or regions. National authorities regulate amateur usage of radio bands. The modes and types of allocations within each frequency band is called a bandplan it may be determined by regulation, but most typically is set by agreements between amateur radio operators. The list of frequency ranges is called a band allocation, which may be set by international agreements, and national regulations. Specific frequency allocations vary from country to country and between ITU regions as specified in the current ITU HF frequency allocations for amateur radio. Radio amateurs use a variety of transmission modes, including Morse code, radioteletype, data, and voice. ![]() Individual amateur stations are free to use any frequency within authorized frequency ranges authorized bands may vary by the class of the station license. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. ![]() Amateur radio frequency allocation is done by national telecommunication authorities.
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