Medium wave or medium
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
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.
on Antennas and Propagation on Medium Frequency
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
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.
on Antennas and Propagation on Low Frequency
"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