The American Radio Relay League (ARRL) Simulated Emergency Test (SET) is a nationwide exercise in disaster response and emergency communication, administered by ARRL emergency coordinators and net managers at the local level, in which volunteer communicators respond to a mock emergency or disaster. Saturday, October 7 was the date for the SET in Maryland/DC.
The scenario for this year’s exercise was a direct hurricane hit on Ocean City, MD (planned before Howard, Irma, Jose, and Maria made their unwelcome appearances). Activities included a fox hunt (i.e., missing-person search), an APRS tracking mission, hospital communications, and Winlink/Winmor message traffic between the Eastern Shore and the rest of the Section.
Here in Montgomery County, members of Montgomery County ARES set up a portable Winlink station in the field to relay message traffic from the Eastern Shore to the rest of the state. Winlink is a worldwide system for sending and receiving e-mail over voice-grade radio channels. In this scenario, given that the distances involved were well-beyond line-of-sight, conventional VHF/UHF two-way communications was not a possibility, so Winlink connections were established using HF (shortwave) radios as the communications medium.
Given the scenario of extensive damage to communications infrastructure in the vicinity of Ocean City, a more realistic approach would have been to use members’ home stations. However, by setting up in a rustic location, we had the opportunity to involve more members and practice setting up a station under austere conditions.
Tom Vegella, K1FEX, arranged for us to use a field at the Izaak Walton League in Germantown, MD. Several of us arrived at the site at the appointed hour of 8 AM on October 7. By 8:30, all of the equipment was on hand. After scouting out the site (which we had not seen beforehand), one team set up the antenna while another set up a tent and assembled the station. We were on the air by 9:50 AM, and passed a message to WB3KAS by Winmor P2P at 10:04 AM on our first try.
Over the course of the exercise, we sent a total of six P2P messages, each to a different station participating in the exercise, and received five P2P messages. We had no difficulty communicating with any of the stations we attempted to connect to. At 3 PM, we declared success and began striking the equipment. In just under an hour, all equipment was packed and loaded into the vehicle, and the site was returned to its natural state.
Our antenna, configured by W3TDH, was a pair of crossed dipoles in an inverted vee configuration. The design is similar to the military AS-2259 antenna, but using dipoles that are resonant on 40 and 80 meters. We had planned to try a Shirley array antenna, but the site didn’t have enough open space.
Although AC power was available from a shed on site, we powered the radio from an 80 Ah LiFePO4 battery supplied by W2LNX. He also provided an small inverter to power the laptop.
We were very fortunate that the forecast rain held off on Saturday. It was pretty muggy early Saturday morning and the mosquitoes were out in force, but around 10 AM a gentle breeze arrived and blew them away. It ended up being a delightful day to be outdoors.
(courtesy of Bruce, W3SCI)
View of site. Tent is an 8-person family tent, modified with “pass-thru ports” at ground level for routing cables in and out of tent.
NVIS Antenna supported by fiberglass sectional mast
Close-up of antenna. At the top of the mast, you see three guy lines, plus a pulley used to support the antenna’s center insulator. The two dipoles for 40 and 80 m slope down at right angles from the center insulator, along with the coax feedline.
View of station. The rack case on the right houses a Yaesu FT-100D HF radio with automatic antenna tuner. Also in this case is a SIgnaLink sound card interface that is connected by USB to the laptop. A separate RS-232 connection between the laptop and the radio permits the Winlink software to tune the radio to the desired frequency. (If everyone looks orange in this photo, it’s not because we have been eating carrots. The light passing through the orange tent makes everything look that way!)
You’ve got mail! (Notice how roomy the tent is.)
Participants included (in no particular order) W3ADP, W3CID, KC3DVT, our host, K1FEX, KC3JFJ, KC3JML, KC3JUY, KC3JVB, W2LNX, N3RQV, K3RYR, W3SCI, W3TDH, AND KN3U, plus future hams Rebecca, Andrew, and Jay.
Winlink messages exchanged with Anne Arundel, Carroll, Howard, Prince Georges, St Marys, and Worcester Counties