About Us
HOTERA
Heart of Texas Emergency Repeater Association
Past and Present
Since 1990, HOTERA has operated FM and D-Star repeater systems in Walburg, Texas, 35 miles north of Austin. The original 145.13 MHz FM system was decommissioned in 2008, when it was replaced with Mode A, B, and C D-Star equipment.
In May, 1989, a storm caused a death and significant property damage in the small town of Jarrell, Texas, 42 miles north of Austin. When they were called by the Williamson County sheriff's department, ARES personnel arrived and found they would have difficulty passing search and rescue and, later, health and welfare messages from the scene. The nearest repeaters were twenty miles or more from the site, and without large antennas, communication to and from the scene was difficult.
After the emergency, several of us decided to build a new FM repeater in the north-central part of the county to provide coverage in emergencies such as the Jarrell event. Funding was received from individuals and through a public service grant from the IBM Corporation. The GE Master II transceiver was donated by sheriff Jim Boutwell, W5LDA. The controller, designed by KV5V, used a CMOS logic state machine, with a bucket-brigade delay IC to suppress the squelch tail. Support was included for up to three receivers, two of which could be located at remote sites. The basic system operated on 145.13 MHz, and the first remote receiver frequency was 444.125 MHz. Battery backup was provided for up to one week of heavy use at reduced power (5 Watts).
The repeater went on the air in May, 1990, and it operated continuously until 2008, when it was decommissioned and replaced with D-Star equipment. It survived a number of episodes of severe weather. In December, 1990, an ice storm loaded the Diamond D-500 antenna with two inches of ice, making the fiberglass radome sway continuously, as if it were a pendulum. There was minor damage to the radials at the base of the antenna, but the repeater never went off the air. In subsequent years, there were direct lightning strikes to the tower (one of which destroyed part of the lighting system), severe winds (which damaged the equipment building), and attacks to the electrical system by fire ants.
On May 27, 1997, central Texas was again visited by severe storms, this time including a Force-5 tornado, which passed through Jarrell, Texas. Police, fire, and medical services were off-line for a time, but the HOTERA repeater, as well as several others in Williamson and neighboring Bell counties, remained on the air to provide basic communication. That storm system spawned tornadoes in five central Texas counties, where there was significant property damage and a number of deaths. (See the January, 1998 QST for a complete report, prepared by Martha Underwood, N2VRF, who lived in nearby Florence, Texas.)
In another weather event several years later, the HOTERA repeater provided emergency communication for Georgetown police and fire department personnel. A large storm cell knocked the combined radio service off-line for several hours. Hams rode in vehicles with police and fire department personnel, using the HOTERA repeater for communication with the county EOC.
Preparing for the changeover to D-Star equipment, HOTERA applied for a station call sign and, on October 5, 2007, was assigned KE5RCS. Steve Bosshard, NU5D, and John Dvoracek, KE5C, neighbors in Bell County, provided advice and assistance in bringing up the new equipment and the Gateway computer. We operated on a temporary antenna at first, but in 2009, Alan Brown, K5AB, and Terry Gerdes, AB5K, installed Mode A, B, and C antennas at the top of the 250 ft. Walburg tower. In the new system, Andrews 7/8-inch hardline carries signals to and from the antennas, and Internet access is purchased from the company which owns and is a co-resident at the site.
The 2-meter and 3/4-meter systems went on the air in early 2008, and the upgrade to Gateway 2 software was accomplished in March of that year. Although it was ordered at the same time as the other equipment, the 23-cm voice and data repeaters were not placed in service until November, 2009, after the Triplexer was received from TX-RX Systems.
Today, the Mode B repeater is normally linked to Ref-004, which is used by D-Star systems throughout the state of Texas. Many out-of-state and off-shore repeaters link to this reflector as well, bringing welcome contacts with hams in other parts of the globe. Since bringing the Mode A repeaters on-line, several of us have experimented with the DD capabilities of D-Star. We have accomplished radio-to-radio connections, radio-to-Internet connections, as well as radio-to-repeater-to-radio digital connections over 30-mile paths. All of these modes are expected to be useful in emergencies. Lower-speed D-Rats data exchanges have also been used on Modes B and C.
With the encouragement of John, KE5C, we have installed an APRS node at the repeater site, and its software and Internet connection are supported by the D-Star Gateway computer. When the Gateway computer hard drive RAID array failed earlier this year because of 130° temperatures in the equipment building, we replaced it with a single solid-state drive. The entire Gateway computer now runs within specs at ambient temperatures approaching 140°F.
D-Star Hot Spots and direct linking with neighboring D-Star systems are being discussed for future projects. In the meantime, it's rewarding to see the D-Star user community in central Texas grow and enjoy this new technology.
Brad Rehm
KV5V
October 19, 2010
Past and present members of the HOTERA Board
of Directors
Tom Casey, WA5ACF Robert Brannon, KC5US (SK)
Phil Duff, NA4M Raye Sorensen, WA4CJC (SK)
Larry Jentry, KB4PR Don Dison, KF7FQ
Brad Rehm, KV5V Mark Stennet, NA6M
Lloyd Jeffries, K1LGJ Ron Yokubaitis, AB5LJ
Alan Brown, K5AB
