Six
Metres is a band of challenges, excitement and a way to increase your adrenalin
at crucial times. To be successful you need to be willing to sit for hours
listening to
band
noises trying to pluck out that weak signal and your operating
techniques
need to be sharp, That is how Steve VK3OT got his DXCC on 50 Mhz.
What
equipment do I need ? Well that depends on your budget and
how
much effort you put in, one watt into a dipole you will work a lot of stations
1000 miles or so on sporadic-e during good openings but you will do better
with ten watts with a small beam, better still if you run 100+ watts
into a large beam.
Receiver
sensitive is most important, most modern commercial ham rigs lack the sensitively
for serious long haul DX-ing ,so a good low noise pre amp is a must.
Band
openings can last for hours to just a few minutes and that is where proper
operating technics come in - If a new country is coming through, that DX
station is going to hear a Dog Pile calling him, you must listen to him
carefully and don't try to call him if he is working another station -
remember the other station he is working could be in another state
which you cannot hear, wait till he announces QRZ DX and calls you
in.
When working the DX station keep the overs short all you need is to exchange signal reports and call signs that is all you need for a valid QSO. If you waffle on others could miss out in working him and you would not be popular!
How do I know when 6 is going to open up? Unless you own a crystal ball, 6 metre openings cannot be 100% predicted but there are signals you can monitor such as distant TV carriers, overseas pagers, two way radios , beacons etc . A good scanner covering 30 to 60 Mhz is a very useful item to have and a wide band aerial such as a discone or an old TV antenna designed for the low TV channels will do. HF signals are not good indicators, I remember one day six metres was wide opened to U.S.A and at the same time 20 Metres was dead, that is while the M.U.F. was above 50 Mhz and at the same time the A.L.F. was higher than 14 Mhz.
PROPAGATION MODES ON SIX METRES
SPORADIC - E
Sporadic - E communications happens with signals refracting of ionized E "clouds" resulting in contacts up to 3000 Kms with very strong signals and sometimes heavy QSB. A sporadic - E opening can last all day.
TRANS EQUATORIAL PROGATION
This
mode of propagation happens when a signal fires across the
equator
via 2 sporadic - e "clouds" one in each hemisphere eg between VK4 and JA.
The TX signal from VK4 hits the cloud in the southern hemisphere then straight
across the equator to the second cloud then down to JA. This type of openings
can last for
long
periods with signals ranging from being very strong to barely readable.
BACK SCATTER
If
a signal hit the e layer or a sporadic e cloud part of the signal can be
reflected back eg a VK5 working a VK3 with both stations beaming north
or north east but not beaming at each other direct, this mode can be useful
for short distance contacts, distances can vary from a few hundred kilometers
to thousands. Signal strength usually depends on power and antenna used.
F2 PROPAGATION
This
is more like HF type propagation when contacts are world wide both short
and long path, this is when a well equipped station comes into play. Signals
refract of the F2 layer of the ionosphere when the MUF is very high, an
important note with this type of progation is - when the MUF is going down
getting very close to 50 Mhz signals can be extremely strong due to low
absorption of the signal but the band can close very quickly when the MUF
goes below 50 Mhz. The MUF can go up to and over 60 Mhz.
TROPO PROPAGATION
This
also known as temperature inversion it is usually happens on hot summer
evenings, bands higher than 50 Mhz enjoy such phenomenon as well. Normally
as the height increases the temperature decreases but some time there can
be
a layer of warm temperatures in the troposphere which can bend the signal
or form a ducting to provide long range communicating over several thousands
of kilometers,
It
is more common along coastal areas more than inland. Antenna polarizing
is very important to make the most of tropo work.
CORDAL HOP
Cordal
hop happens when signals skip between the upper f layers of the ionosphere
coming out the end half around the world. Not too much is known about
this mode of propagation but to make the most of cordal hop it is an advantage
to have a well equipped station with reasonable power and antennas.
AURORAL PROPAGATION
Auroras which put on spectacular light shows near the poles can also reflect radio signals eg VK3 to VK5/7 with extreme auroral distortion. To make use of the aurora, CW is the best mode of transmission or on SSB speak very slowly, levels of distortion can be nearly 100% and fairly weak signals.
E.M.E.
EME contacts using the Moon as a reflector requires a super six metre station you need to run very high power, extremely sensitive receivers connected to large antennas arrays on a fairly large real estate.This mode would be out of reach by most hams.
This
sums up this page, hope you found it interesting and please E-mail me with
any comments.
73 Lionel VK3NM VK6DC