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What services
are available?
The Amateur Radio Emergency Service (ARES) can perform a
variety of voice, data, image or direction finding services.
Voice Communication:
The most commonly used mode is VHF/UHF FM voice.
The equipment requirements are modest and all Santa Maria ARES members
can provide this mode. Mountain top repeaters extend the range of
small portable or mobile equipment over a large area. The local
ARES repeater (AD6EA) has a "phone patch" which allows
a user to place local telephone calls.
For areas outside the normal coverage of permanent repeaters, a
"portable" repeater is available which can be linked to
the local repeater or operate independently.
Another voice mode available is High Frequency (HF) Single Sideband
(SSB). HF equipment costs and licensing requirements are greater
than for VHF FM, therefore, many, but not all, members have this
capability. HF communication can reach throughout the area, the
state or the world depending on various factors. For ARES work,
the ability to reach into areas not served by repeaters (such as
canyons or wilderness areas) or stations outside of the region without
the aid of any infrastructure is important.
Data
modes:
E-mail and file transfer are possible using "Packet" radio.
Using the sound card of a computer or a device similar to a telephone
modem, data can be transmitted between radios. The advantages compared
to voice are speed and accuracy. Groups of packet stations can be
configured into networks with automatic message forwarding between
mailboxes. It is also possible to integrate packet radio into the
Internet e-mail system through the use of the TCP/IP protocol or
through e-mail gateways stations.
The Automatic Position Reporting System (APRS) is a combination
of packet radio with the GPS system. Stations periodically send
position (and/or weather) reports over a network of packet repeaters.
This system is fully integrated into the Internet and the results
can be displayed
in a web browser. Simple messages can be sent between stations and
it is possible to send a message via Internet e-mail. Tracking moving
vehicles and weather observations are the two primary uses of APRS
by ARES.
Image
modes:
Pictures can be sent from one station to another
via two different systems:
Slow Scan TV can send a still color picture across a HF or VHF/UHF
link in about a minute. The image source can be a digital camera,
video camera or scanned image. Both self contained units or computers
running special sound card software can be used to transmit or receive
images.
Fast Scan TV is similar to conventional television, full motion
color pictures with sound. FSTV must use UHF or higher frequencies
and a device called a downconverter allows a regular TV to be used
for reception.
Radio
Direction Finding:
Through the use of directional antennas and/or specialized
receivers, it is possible to determine the direction to a transmitter
of a radio signal. All aircraft carry transmitting beacons called
Emergency Locator Transmitters (ELT) that are activated automatically
in the event of sudden impact. A ELT direction finding receiver
was donated to the Santa Maria ARES by Ltronicis and several members
have been trained in its use. Throughout Santa Barbara Country are
several amateur radio operators with this equipment and some of
the area repeaters have ELT monitoring alarm systems installed.
Another use of RDF is locating sources of intentional or unintentional
interference.
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