Baldwin County AMATEUR RADIO CLUB - BCARC
PROJECTS AND EXPERIMENTS
JANUARY 2017 - WSPR
WSPR (pronounced "whisper") stands for "Weak Signal Propagation Reporter". It is a computer program used for weak-signal radio communication between amateur radio operators. The program was initially written by Joe Taylor, K1JT, but is now open source and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands. These low power transmissions can be as low as 200 milli watts, or lower. Radio beacon transmissions have been sent out from the United States and heard all around the world - on less than a watt of radio frequency power.
The BCARC amateur radio club has been experimenting with a locally designed and built digital transmitter on a PC board device that couples with a Raspberry Pi, a single-board computer developed in the United Kingdom by the Raspberry Pi Foundation to promote the teaching of basic computer science in schools and in developing countries. Using the Raspberry Pi and our home brew transmitter combination, the members of the club have been able to successfully transmit a beacon signal at very low wattage, and be heard all over the North American continent and parts of Europe.
The Raspberry Pi 3.0 device gets its power from a 2 watt USB power supply and supports and additional 4 USB slots. It also supports an Ethernet port and a micro SD slot so that additional software can be made available to the device's built in control software.
The home brew device is a circuit board (pcb) that plugs into the rPi 40-pin header. It boosts the signal level to about 200 mW and contains a seven pole low pass filter to keep out-of-band transmissions down by 45 dB. It also contains an LED the lights when transmitting and a crude output power indicator.
February 2017 - Amateur Radio Emergency Data Network - AREDN
"An Amateur Radio Emergency Data Network (AREDN™) is a high speed data network built with Amateur Radio Operators and Emergency Communications Infrastructure in mind.
AREDN™ is self-configuring and self-healing. Where possible, AREDN™ will establish connections with as many other AREDN™ compatible devices (nodes) as possible and form a redundant mesh like network.
AREDN™ nodes automatically finds the “most reliable” nodes (greatest chance of success on packet delivery) to attempt delivery of the packets sent across the network. One need not know the exact path to get to the destination, only to know what the destination is."
From the national AREDN website: http://www.aredn.org
An AREDN mesh network is an implementation of a wireless data networks over amateur radio frequencies using commercial off-the-shelf (COTS) hardware such as 802.11 access points and D-STAR equipment. Only licensed amateur radio operators may use amplifiers and specialized antennas to increase the power and coverage of the 802.11 signal.
The BCARC amateur radio club has worked hard with other hams in Mobile and Baldwin County to establish a multi-node mesh network that will support an emergency communications network, should such be needed.
On a recent Saturday morning, some of the BCARC members met at the Lake Forest Yacht Club parking lot to setup a portable 40 ' mast which supported a high gain AREDN antenna. With the antenna connected to a laptop so as to monitor the access point's built in software, the group was able to connect to and see nearby nodes on the AREDN network.