[6] How do bands, wavelengths & frequencies, kHz & MHz, differ? A band can refer to any choice from a set of tuning ranges on a given radio, as well as any sub-range of frequencies 'on the dial'. Some antique radios have dials calibrated according to wavelength (as a whole number of metres) instead of frequency (kHz or kcps) to convey tuning location: e.g. the "16m" position on such dials is within a sub-range of frequencies whose wavelengths border on 16 metres. * To convert MHz to kHz, multiply the former by 1000 kHz/MHz: 9.625 MHz x 1000 kHz/MHz = 9625 kHz * To convert kHz to MHz, divide the former by 1,000 kHz/MHz: 21,725 kHz divided by 1,000 kHz/MHz = 21.725 MHz * To convert kHz to metres, divide 299,792 km/s by the former: 299,792 km/s divided by 7,135 kHz = 42.02 m * To convert metres to kHz, divide 299,792 km/s by the former: 299,792 km/s divided by 14 m = 21,414 kHz 299,792 km/s divided by 15 m = 19,986 kHz 299,792 km/s divided by 16 m = 18,737 kHz 299,792 km/s divided by 17 m = 17,635 kHz 299,792 km/s divided by 19 m = 15,779 kHz 299,792 km/s divided by 21 m = 14,276 kHz ( Note that as frequencies get lower, wavelengths get longer.) Low Frequencies The 30 - 300 kHz range is known as the low frequencies' band, for which 'longwave' is a synonym. Reception for this range is best between 6 p.m. & midnight (your time). Many longwave stations serve as beacons for aircraft and marine navigation by continuously transmitting their call letters. Many broadcasts use Morse code (CW), but some transmit in binary coded decimal (BCD), such as the time station WWVB on 60 kHz. On longwave, there is an AM broadcast band from 153 to 279 kHz in Europe, N. Africa and N. Asia, but in America the only AM voice broadcasts are typically weather reports. Medium Frequencies The medium frequencies' band is between 300 & 3000 kHz. On mediumwave, there is an AM broadcast band from 525 to 1600 kHz, extended to 1700 kHz in Argentina, Australia and the U.S. A few more stations are between 2300 & 2500 kHz, particularly in Australia & Brazil. Coastal shipping uses 415 - 535 kHz: three CW calling & distress stations monitor 500 kHz in Arctic Canada; internationally, most NavTex automated warning stations use 518 kHz. Similarly, other coastal stations & boats, especially coast guards and pleasure boaters, have use of 2000 - 2300 kHz, with 2182 kHz set aside internationally as a voice calling & distress channel. Spanning the 160 metre dial position, there is an amateur radio band from 1800 to 2000 kHz. Most of the transmissions are in SSB mode. High Frequencies The 3,000 - 30,000 kHz range is known as the high frequencies' band, for which 'shortwave' is a synonym. Certain sub-ranges are set aside as 'band allocations' for specific purposes, such as for: Aircraft, Amateur Radio, Citizens' Band Radio, International Broadcasts, Ships & Coastal Stations. Aircraft Frequencies Aircraft on trans-oceanic routes often use shortwave, mostly in SSB although AM mode might still be used, to communicate with air traffic controllers. Here are some bands where you might hear them: 2,850- 3,155 kHz 3,400- 3,500 kHz 4,650- 4,750 kHz 5,450- 5,730 kHz 6,525- 6,765 kHz 8,815- 9,040 kHz 10,005-10,100 kHz 11,175-11,400 kHz 13,200-13,360 kHz 15,010-15,100 kHz 17,900-18,030 kHz 21,870-22,000 kHz 23,200-23,350 kHz Amateur Radio ('ham') Frequencies Scanning the amateur radio frequencies can be interesting and also helpful at times, because amateur radio operators often broadcast emergency information when other means of communication break down: e.g. the Salvation Army Team's Emergency Radio Net on 14,265 kHz in USB mode. One may obtain a basic licence to transmit only above the HF band, after passing just a written exam. Those who qualify for the more senior amateur licences may also transmit on shortwave, but must also pass a proficiency test for sending messages via Morse code in CW mode. However, in many countries such tests are no longer required (e.g. Australia, Chile, New Zealand & Papua New Guinea), or will be phased out. As shown below, voice operators usually transmit in a band just above that for code. ...wavelength.....code.band.............voice.band......... ....(metres)........(kHz)..................(kHz)........... 80 3,500 - 3,750 3,750 - 4,000 56 (5,167.5- 5,403.5) 42 7,000 - 7,150 7,150 - 7,300 30 10,100 - 10,150 21 14,000 - 14,150 14,150 - 14,350 16 18,068 - 18,110 18,110 - 18,168 14 21,000 - 21,200 21,200 - 21,450 12 24,890 - 24,930 24,930 - 24,990 10 28,000 - 28,300 28,300 - 29,700 Note: These designations are not observed everywhere (including the United States - the first country to open up five USB channels bordering on 56 metres to hams). American CB Frequencies (applies partly to Oceania: Guam, etc.) 65 frequencies around 11 metres are allocated as channels 10 kHz wide with a separation of 10 kHz from 26,895 to 27,535 kHz. The 40 channels designated for voice communications from 26,965 to 27,405 kHz comprise the Citizens' Band, and the rest are set aside for other uses such as controlling objects. The 11 metre wavelength is within CB Channel 23 (centred on 27,255 kHz). In North America, Channel 19 (27,185 kHz) is often used as a highway information channel; Channel 9 (27,065 kHz) is reserved for emergency use. Unlike for ham radio, a licence is not required for CB transmissions. Most of these are in AM mode, but a few CB radios can use SSB, such as the Realistic TRC-459: http://support.radioshack.com/support_electronics/doc46/46897.htm International Broadcast Frequencies Frequencies in shortwave bands near the following 13 wavelengths are allocated as channels 10 kHz wide with a separation of 5 kHz for use by foreign and domestic stations. Their broadcasts are mainly AM transmissions containing news, commentary, music and special features reflecting their own country's cultural canvas. You can often find more such stations transmitting just above or below these bands: 90 m * 3,200 to 3,400 kHz 75 m ** 3,900 to 4,000 kHz 60 m * 4,750 to 5,060 kHz 49 m 5,900 to 6,200 kHz 41 m ** 7,300 to 7,550 kHz 31 m 9,400 to 9,900 kHz 25 m 11,600 to 12,100 kHz 22 m 13,570 to 13,870 kHz 19 m 15,100 to 15,700 kHz 17 m 17,480 to 17,900 kHz 15 m 18,900 to 19,020 kHz 13 m 21,450 to 21,850 kHz 11 m 25,670 to 26,100 kHz * These bands are reserved for transmissions with tropical coverage. ** Interference can be heavy around 41 & 75 metres, because hams in many countries may operate here. Ship & Coastal Station Frequencies Most HF voice transmissions from ships & coastal stations are in SSB. You can hear these transmissions in the following bands: 4,000- 4,143 kHz 4,351- 4,435 kHz 6,200- 6,525 kHz 8,100- 8,815 kHz 12,230-12,420 kHz 13,107-13,200 kHz 16,360-16,565 kHz 17,100-17,410 kHz 18,780-18,900 kHz 19,680-19,800 kHz 22,000-22,855 kHz 25,070-25,210 kHz 26,100-26,175 kHz WWV broadcasts marine weather conditions for the NW Atlantic 8 minutes past the hour; WWVH for the Pacific 48 minutes past; and each for the NE Pacific 10 & 51 min. past with a status report for GPS satellites 14 & 52 min. past, respectively, on frequencies as given below. Time & Standard Carrier Frequencies The following stations broadcast their carriers exactly on-frequency, which is useful to also calibrate SSB fine-tuning dials or BFOs (even on some digitally-tuned radios). They also signal the exact time of day at regular intervals (24 hours a day in standard AM mode except where noted) which can be used to calibrate GPS devices. The time is stated in terms of UTC. Most international broadcasts are scheduled according to UTC, rather than the originating station's time zone. CHU at Ottawa, Ontario: 3,330 & 7,850 & 14,670 kHz (all in a fully 'AM-compatible' SSB mode: USB + full carrier) LOL at Buenos Aires, Argentina: 11-12h, 14-15h, 17-18h, 5,000 & 10,000 kHz 20-21h, 23-24h UTC WWVH at Kekaha, Hawaii and (or) WWV at Fort Collins, Colorado: 5,000 & 10,000 & 15,000 (& 20,000) kHz YVTO at Caracas, Venezuela: 5,000 kHz (USB) _________________________________________________________________ optimised for screen reading in pine