VK3ACA 's

MEDIUM WAVE & LONG WAVE  PAGE


Medium Wave

 Medium wave or medium frequency according to current standards includes wave lengths from 100 to 1000 metres or 3000 kHz to 300 kHz. and includes the broadcast band,  about 531 kHz to 1638 kHz and higher. According to  an earlier European standard medium frequency included  100 to 1500 kHz and the band from 1500 to 6000 kHz was called medium high frequency. The band tends to divide its self into several parts depending upon characteristics and usage.  The low frequency side of the broadcast band is used for navigational aids such as marine and aeronautical and for marine ship to shore. All transmissions in this band are vertically polarized and depend on ground wave in the primary service area. Similarly in the broadcast band. The band above the broadcast band between 1640 and 3000 is used for navigational aids, "amateur radio" and broadcasting. Vertical polarization is used by navigational aids which rely on ground wave. Amateur radio uses both vertical and horizontal polarisation in the band 1800 1875 kHz in Australia, (other countries have smaller or larger allocations). Amateurs use mainly ground wave both day and night for short range (up to 50 km) and occasionally short skip sky wave (up to 200 km) in the day and short to long distance sky wave at night. Long distance sky wave signals in this band are more variable, weaker and less predictable than on higher frequency bands and usually requires the use of morse code using CW (keyed continuous waves). Difficulties experienced in long distance propagation on medium frequencies are looked on as a challenge by some radio amateurs. Broadcast usage above the main broadcast band and up to 3 MHz rely on short skip sky wave. Usually the higher the frequency the greater the night time coverage.

Articles on Antennas and Propagation on Medium Frequency

The article below was published in "Amateur Radio" magazine (Wireless Institute Australia), May to August 1971. The purpose of the article was to show what could be done with a back yard antenna and to compare the usefulness of vertical polarisation with horizontal polarisation for both transmitting and receiving.

The Home Station Antenna for 160 metres

The following article "Notes on propagation of medium frequency waves." is a general observation on the subject along the lines of the article "Propagation of long Radio Waves" and is the text of a discussion between Walter Schulz and my self.


The Following references are to some articles on chordal propagation referred to in the article above on medium frequency propagation. The references don't all specifically refer to MF.


Articles on Antennas and Propagation on Low Frequency

The article "Propagation of Long Radio Waves" was published in "Amateur Radio" magazine September 1991,  (Wireless Institute Australia). The article was presented in the Long Wave Club of America web site for approximately 8 years. The article is available here below.


 Visit "The Long Wave Club of America"