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BARRETT 4050 HF SDR TRANSCEIVER - OPERATING AND INSTALLATION MANUAL
Factors Which Affect HF / SSB Communications
There are a number of different factors which will affect the success of commu-
nications via HF / SSB radio. These are outlined below:
Frequency Selection
Frequency selection is perhaps the most important factor that will determine
the success of your HF / SSB communications.
Generally speaking the greater the distance over which you want to communi-
cate, the higher the frequency you should use.
Beacon Call, a Selcall (Selective Call) function built into the Barrett Transceiver,
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Network Transceivers all having a selection of frequencies that will accommo-
date most ionospheric conditions. When in standby, the network Transceivers
scan these frequencies waiting for a call (Selcall or Beacon Call) from another
Transceiver. The Transceiver wishing to check for the best frequency to operate
on sends a Beacon Call to the station to be contacted. If the call to the other
station is successful, a revertive tone from the station being called will be
heard, indicating the channel selected was suitable for the ionospheric condi-
tions prevailing. If the revertive tone is not heard or is very weak, another chan-
nel may be tried until a revertive tone of satisfactory signal strength is heard.
(Refer to Beacon Calls on page 32 for more details.)
Time of Day
As a rule, the higher the sun, the higher the frequency that should be used.
This means that you will generally use a low frequency to communicate early
morning, late afternoon and evening, but you will use a higher frequency
to cover the same distance during times when the sun is high in the sky (for
example, midday). You will need to observe the above rule carefully if your
Transceiver has a limited number of frequencies programmed into it, as you
may only be able to communicate effectively at certain times of the day.
Weather Conditions
Certain weather conditions will also affect HF / SSB communications. Stormy
conditions will increase the background noise as a result of static caused by
lightning. This background noise could rise to a level that will blank out the
signals you are trying to receive.
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