[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)
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