latest news

2.15.2009

Repeater News. The Club's Vice President Curt Justice KF4OFI installed a new audio delay board in our repeater's controller. This will enhance it's performance by eliminating  any squelch tail after you unkey the machine.  

other information

This club is affiliated with the American Radio Relay League.

The WR4rc-3 Digipeater and aprs

WR4RC-3 Digipeater

The Russell County Amateur Radio Club, Inc. installed a new APRS Digipeater at the WR4RC repeater site in Hansonville VA. This system has many uses in emergency communications such  as:

 

High-Altitude Ballooning
Direction Finding
Search and Rescue
Send Internet E-mail
Short Text Messaging
Telemetry
Tracking
Voice Alert
Weather Reporting

Click on screenshot for larger picture

Automatic Position Reporting System

APRS is an amateur radio based digital communications system for local, tactical, real-time exchange of information among all members of a net, including map based displays for situational awareness. It was developed by Bob Bruninga, WB4APR, who currently works at the United States Naval Academy.

Capabilities

APRS is used to transmit real-time information such as messages, bulletins, announcements and the locations of any stations or objects via amateur packet radio protocols. Real-time reporting of station position for mobiles is facilitated using the Global Positioning System. APRS is capable of transmitting a wide variety of data including weather reports, short text messages, radio direction finding bearings, telemetry data, and storm forecasts. These reports can be combined with a computer and mapping software to show the transmitted data superimposed on a variety of map displays.

Technical Information


 In its most widely used form APRS is transported over the air using the AX.25 protocol at 1200 baud Bell 202 audio frequency-shift keying on frequencies located in the amateur 2-meter band . An extensive digital repeater, or digipeater network provides transport for APRS packets on these frequencies. Internet gateway stations (i-Gates) connect the on-air APRS network to the APRS Internet System (APRS-IS), which serves as a worldwide, high-bandwidth backbone for APRS data. Stations can tap into this stream directly. Databases connected to the APRS-IS allow web-based access to the data as well as more advanced data mining capabilities. A number of low-earth orbiting satellites and the International Space Station are capable of relaying APRS data.

History
Bob Bruninga implemented the earliest ancestor of APRS on an Apple II computer in 1982. This early version was used to map high frequency Navy position reports. In 1984, Bruninga developed a more advanced version on a Commodore VIC-20 for reporting the position and status of horses in a 100-mile endurance run. During the next two years, Bruninga continued to develop the system, which he now called the Connectionless Emergency Traffic System (CETS). Following a series of FEMA exercises using CETS, the system was ported to the IBM PC. During the early 1990s, CETS, now known as the Automatic Packet Reporting System, continued to evolve into its current form. As GPS technology became more widely available, 'Packet' was replaced with 'Position' to better describe the most common use of the system.

 

APRS Frequencies

Primary VHF Networks


North America: 144.39 MHz (Voice Alert 100.0 Hz CTCSS, mobiles only please!)
Europe: 144.80 MHz
Australia: 145.175 MHz (Voice Alert 91.5 Hz CTCSS)
(Thanks to Gerard VK2JNG for the Correction on the Australia info)
New Zealand: 144.575 MHz
Argentina: 144.930 MHz
Japan: 144.640 MHz

Alternative Input VHF Networks


For low-powered trackers only:

Many areas: 144.99 MHz
Western Washington State: 144.35 MHz

UHF Networks


Australia (VK): 439.100 MHz 1200 baud (in selected areas)
Puget Sound, WA: 440.875 MHz 1200/9600 baud
Kansas / Missouri: 446.175 MHz 1200 baud (primary, with infrastructure)
Kansas / Missouri: 441.175 MHz 1200 baud (secondary / special event, no infrastructure)

HF Frequencies


Dial frequencies based on default tones used in popular packet devices.

30 meters, 300 baud packet, Worldwide


 
USB Dial Frequency Mark Frequency LSB Dial Frequency
KAM, MFJ, TinyTrak 10.147.600 MHz 10.149.200 MHz 10.151.000 MHz
AEA 10.147.100 MHz 10.149.200 MHz 10.151.500 MHz


 

Satellites

Satellite Uplink Frequency Downlink Frequency Alias Mode Status
ISS 145.990 MHz 145.800 MHz ARISS 1200 baud AFSK packet Active
PCSAT-2 145.825 MHz 435.275 MHz ARISS or WIDE2-2 1200 baud AFSK packet Active
PCSAT-1 (NO-44) 145.825 MHz 145.825 MHz ARISS 1200 baud AFSK packet Daylight Ops Only!
AO-51 (Echo) 145.860 MHz 435.150 MHz PACB-1 9600 baud FSK packet Active (see schedule)


Satellites are subject to doppler shift and you should adjust your uplink/downlink accordingly. Doppler will make the frequency on a LEO shift as follows:

 

2 meters - +/- 3kHz (FM capture effect negates the need to adjust on this band)
70 cm - +/- 10kHz
 

 

 

 

 

 

 

 

 

 

 

 

 

Here is the location of the WR4RC-3 Digipeater. Click here for a map of all local stations near WR4RC-3.

Click here to find the Mobile APRS station N4ZZQ-12.  This is Al Keen's Jeep with an onboard tracker.

Check out Google APRS. Its Live internet APRS data streamed to a Google map. Click and Zoom anywhere.