About HF SSB radio communications To gain a better understanding of the unique benefits HF Communications can provide, we have created a HF Communications overview video tutorial and a HF Network setup examples video tutorial. HF Communications overview video tutorial

This tutorial explains the basics of HF propagation and how HF SSB communication works.
HF Network setup examples video tutorial

This tutorial gives examples of how to setup HF Communications stations and explains how they can be used to create a complete non-satellite based communications network for use in remote areas where there may be no other infrastructure.


About HF propagation
>> Ground-wave which travels directly from the transmitting antenna to the receiving antenna following the contours of the earth.

Generally speaking, ground-wave is used to communicate over shorter distances usually less than 50km. Because ground-wave follows the contours of the earth, it is affected by the type of terrain it passes over. Ground-wave is rapidly reduced in level when it passes over heavily forested areas or mountainous terrain.

>> Sky-wave which travels upward and at an angle from the antenna, until it reaches the ionosphere (an ionised layer high above the earth's surface) and is refracted back down to earth, to the receiving antenna.

Sky-wave is used to communicate reliably over medium to long distances up to 3,000km. Whilst the nature of sky-wave propagation means it is not affected by the type of terrain as in ground-waves it is affected by factors involving the ionosphere as described below.

>Factors which affect HF/SSB communications
>> 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 communicate, the higher the frequency you should use.

Beacon Call, a Selcall (selective call) function built into the Barrett 2000 series transceiver, makes finding the correct frequency to use easy. Beacon call is based on the network transceivers all having a selection of frequencies that will accommodate 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 he wishes to contact. If his call to the other station is successful he will hear a revertive call from the station he is calling, indicating the channel he selected was suitable for the ionospheric conditions prevailing. If he does not hear this revertive call or it is very weak, he tries on another channel until a revertive call of a satisfactory signal strength is heard.

>> 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 (e.g. 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.

>> Man-made electrical interference Interference of an electrical nature can be caused by overhanging power lines, high power generators, air-conditioners, thermostats, refrigerators and vehicle engines, when in close proximity to your antenna.

The result of such interference may cause a continuous or intermittent increase in the level of background noise.

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Barrett has a long held reputation for the supply and support of HF communications equipment to the aid and humanitarian markets.

Barrett HF equipment provides easily installed, simple and reliable voice and HF based email communications in areas that have either poor communications infrastructure or where previous communications infrastructure has been destroyed.

Our commitment in the form of regular field support trips to assist in mission start ups throughout the world is well known.

Organisations and missions supported include:
. UNDPKO . UNAMA . Red Cross
. UNMET . Red Crescent . UNMOGIP
. UNMIL . UNAMI . UNAMSIL
. UNMID . UNICEF . UNIIC
. WFP

Barrett products suitable for use in these areas include:
Barrett 2050 HF transceiver
Barrett 2019 Automatic tuning mobile antenna
Barrett 2050 Wireless control HF transceiver
Barrett 2060 Automatic telephone interconnect
Barrett 2020 HF email system
Barrett 2062 HF-VHF/UHF crossgate
Barrett HF communications equipment provides vital communications for law enforcement and security organisations internationally.

Security organisations in places such as Iraq, Timor, Kazakhstan, Papua New Guinea, Solomon Islands and a number of African and South American countries have utilised Barrett's communications products where reliable and secure communications are paramount.

These organisations include:
. Police forces
. National Guard
. Customs
. Border Patrol
. Coast Guard
. Drug enforcement agencies
. Private security firms

Barrett products suitable for use in these areas include:
Barrett 2050 HF transceiver
Barrett 2019 Automatic tuning mobile antenna
Barrett 2050 Wireless control HF transceiver
Barrett 2060 Automatic telephone interconnect
Barrett 2020 HF email system
Barrett 2062 HF-VHF/UHF crossgate
Barrett HF communications equipment is ideally suited to provide primary and backup communications for the following

Public sector areas that include:
. Remote health provision . Forestry
. Telecommunications . Post
. Emergency services . Transport
. Agriculture . Fisheries
. Environmental protection . Energy
. Embassies . Consulates

Private sector industries that include:
. Mining . Agriculture
. Construction . Energy
. Transportation . Shipping

We also serve a significant recreational vehicle user market.

Barrett products suitable for use in these areas include:
Barrett 2050 HF transceiver
Barrett 2019 Automatic tuning mobile antenna
Barrett 2050 Wireless control HF transceiver
Barrett 2060 Automatic telephone interconnect
Barrett 2020 HF email system
Barrett 2062 HF-VHF/UHF crossgate
Barrett 2075 300 W to 1 kW HF transmitters
Our turnkey network design team will take your system requirements and produce an initial technical proposal.

On customer approval this initial technical proposal is finalised into a detailed technical document with system manuals and full installation programs.

Barrett turnkey systems have been used in areas that include:
HF systems for Air Traffic Control
Remote sited HF transmitters and receivers linked by landlines or microwave
LAN based control systems for remote sited HF transmitters and receivers
Operator consoles, Custom built interfaces, control systems, operator positions
MIL-STD HF data systems including 5066 stack based systems
Integration of new HF transmitters and receivers into existing systems
Turnkey mission based installations for humanitarian organisations
Vehicle tracking systems
High power transmitters for GMDSS systems
High power HF email and data systems
Military HF networks

All Barrett Communications products can be incorporated into a custom turnkey HF network depending on customer requirements.
Barrett 1 kW high power HF transmitters and remote HF receivers along with our 2076 remote site interface are used in conjunction with TransOceana DSC systems for GMDSS coast stations.

GMDSS coast stations that include Barrett equipment have been installed in various countries including Mauritius, Namibia and Thailand.

Barrett products used in these applications:
Barrett 2075 high power transmitters
Barrett 2050 HF receivers
Barrett 2076 remote site controllers
Barrett 2071 HF Rx multi-coupler
Barrett 912 broadband dipoles
Barrett 902 series masts
Military forces rely on HF and low band VHF radio to provide secure and highly reliable communications in demanding applications and environments.

Barrett HF radio and low band VHF communications equipment are more secure, autonomous and resistant to jamming than other communications mediums.

Barrett HF tactical transceivers provide:
. MIL-STD 188-141B ALE
. Frequency hopping
. AES and DES voice encryption

Barrett low band VHF tactical transceivers provide:
. Voice and data encryption
. Frequency hopping

Barrett products suitable for use in these areas include:
Barrett PRC-2090 tactical HF system
Barrett PRC-2080 tactical VHF system