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 Previous: Ham Operators to Provide Super Bowl Support |  Next: Surfin': The Digital Domain |
 The Kodiak Star launcher heading into space last September with PCsat and other amateur and non-amateur payloads aboard. |
NEWINGTON, CT, Feb 1, 2002--Walk outdoors with a packet-equipped H-T and send a message while PCsat is flying overhead, and it will get to anyone, anywhere in the world within seconds! So says Bob Bruninga, WB4APR, about the PCsat Amateur Radio satellite. This functionality comes from a "bird" that was constructed on the cheap using commonly available components--including a tape measure from Home Depot for an antenna.
"PCsat is going great, and we are very pleased to see about a dozen users on it on every pass," Bruninga said.
Short messages can be sent point-to-point via PCsat to other amateurs just about anywhere on Earth, assuming the recipient has his or her radio turned on and is tuned to the local Automatic Position Reporting System (APRS) frequency. One-line messages also can be sent for e-mail delivery via the Internet.
Built last year
under Bruninga's tutelage by midshipmen at the US Naval Academy, PCsat--the
acronym stands for "Prototype Communications Satellite"--cost something like
$50,000 altogether. And, as an Associated Press report on PCsat pointed
out recently, that even included the cost of the airline tickets to Alaska,
where PCsat was launched with other Amateur Radio payloads by the Kodiak Star
launcher.
 Bob Bruninga, WB4APR (center), looks on as ensigns Dan Boutros (left) and Brad Schwenzer (right) describe PCsat's telemetry sub-module. |
Even Bruninga found himself amazed by the satellite's messaging capabilities. "Since any packets digipeated by PCsat are picked up by various sat-gates and injected into the world-wide APRS Internet stream," he said, "then if the packet is a message to someone, it will come out the other end--live--back to RF in his area for delivery on his local APRS frequency anywhere in the world!" He said the Amateur Radio on the International Space Station packet system has similar capability.
"Of course, one should be more amazed when it does work, than when it doesn't," Bruninga said. "After all, this is ham radio." Even so, he said it demonstrates the power and potential of PCsat, the ARISS packet system "any other digipeating satellite" to get a message for the traveler out and delivered via the amateur satellites and satellite monitoring sat-gates.
 The VHF transmitter board in PCsat was built using easy-to-find, low-cost components. |
"So for fun," Bruninga suggested, "instead of sending your boring grid square or position, try sending someone an e-mail via satellite!" from your packet station. As an APRS digipeater, PCsat is designed to relay UI (Unconnected Information) packets, and no connections are permitted. Uplinks are at 1200 and 9600 baud on 145.827 MHz and 435.250 MHz, respectively. All downlinks are at 1200 baud on 145.827 MHz.
"Set your UNPROTO to 'UNPROTO APRS VIA NOCALL' and it will work via either the ISS or PCsat," Bruninga explained. "People feed both downlinks into the worldwide APRS Internet system, where they will go everywhere."
Bruninga says to send an "e-mail" while using APRS software, "just send a message to 'EMAIL' and make the first word of the email be the recipient's e-mail address." For those not using APRS software, Bruninga advised using an APRS message consisting of this data format:
:xxxxxxxxx:message goes here {n .
Bruninga says that ":xxxxxxxxx:" is a fixed-length nine-character 'TOCALL' field padded with spaces and bracketed by colons. It ends with a line number preceded by "{".
Details on using PCsat are on the PCsat Web site.
| Previous: Ham Operators to Provide Super Bowl Support | Next: Surfin': The Digital Domain |
