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Thursday, June 14, 2001
Research in Radio and Microwave circuits and Antennas [source: Simi Settlers Radio Club and Caltech>
Professor Rutledge's research group is building circuits and antennas for a range of applications at frequencies from 1MHz all the way up to 1THz. Radio and microwave circuits are the core of the wireless communications revolution and play a central role in radars, remote sensing, and satellite broadcasting. Our research is in quasi-optical powercombining, micro-electo-mechnaical systems (MEMS) for RF and microwave circuits, and Class-E amplifiers for communications transmitters. The goal of the work in quasi-optical power combining is to make powerful solid-state oscillators and amplifiers. In recent years, there have been spectacular increases in the operating frequencies of solid-state devices. Gallium-arsenide transistors are now available that operate at frequencies as high as 200 GHz. At the same time, however, the output powers at these high frequencies are very low, and it is clear that the outputs of hundreds or thousands of devices must be combined to make a high-power transmitter. Caltech has pioneered the development of radically different microwave circuits called active grids that directly produce and amplify microwave beams. Active grids are periodic metal patterns loaded with transistors and diodes. These circuits should greatly increase the output power of transmitters and improve the noise and saturation levels of receivers. The circuits are redundant, and this makes them less likely to fail. At the same time, active-grid circuits have fewer parts by far than conventional microwave circuits. We have recently demonstrated a grid with 72 transistors that produces 0.6 W at 40 GHz. We have completed a micro-electromechanical systems project, MEMS, demonstrating a sliding backshort that tunes a 600-GHz circuit. We are now developing MEMS switches with the Rockwell Corporation for electromechanically steering a 90-GHz radar beam and are studying the use of MEMS capacitors and inductors in high-power transmitters. We also have projects in high-power Class-E amplifiers for communications transmitters, semiconductor plasma processing, and magnetic-resonance imaging. Our amplifiers use power MOSFETs. Our amplifiers have an efficiency of 90% and output powers of up to 500 watts. Recent work has indicated that it should be possible to use PHEMT devices in Class-E amplifiers at 10GHz. The group has developed a computer-aided-design program, called Puff 2.1, for microwave integrated circuit lay-out and design on IBM-PC's.The program analyzes microstrip and stripline circuits, and is widely used around the world, with more than 20,000 copies in universities, government laboratories, and industry. Research in Radio and Microwave circuits and Antennas RF and Microwave Research Group Page Wednesday, June 13, 2001
Computer troubleshooter can't get enough action By Janie Magruder The Arizona Republic June 13, 2001  By day, Dan Danz works as a computer troubleshooter; by night, he works for the Maricopa County Sheriff's Office. [photo: Pat Shannahan/The Arizona Republic] Like many cub reporters, Dan Danz was a siren chaser who listened to his police scanner night and day, always ready to dash out if a fire broke out or a shooting occurred. He left his television news job in San Antonio 30 years ago and went into computers to make a better living, but he never lost the taste for a good police chase. Which is why, four years ago, the Fountain Hills resident asked his wife, Judy, for a police radio for Christmas, then several months later began exploring the notion of becoming a dispatcher for the Maricopa County Sheriff's Office. After 50 hours of training, Danz, 61, took his place in 1998 at the console as a radio dispatcher and 911 operator, deftly handling calls about armed carjackers, mad spouses, lost hikers and troublemaking teenagers. Both his day job, as a senior technical consultant for Stratus Technologies, and his moonlighting post require quick, thoughtful decisions in often stressful conditions. "I've come to the realization that I thrive on action - I guess that's why I trade one kind of pressure for another kind three times a week," says Danz, who works 19 hours a week at the sheriff's department. "The abrupt change really helps put things in perspective in both directions. For example, sometimes when I have a demanding computer user who's claiming that his problem is an 'emergency,' I smile inwardly, remembering some hot traffic on the sheriff's radio system the previous night and think, 'Buddy, let me tell you about a real emergency'." Danz keeps careful notes of his experiences with the Sheriff's Office. Three of the most memorable: • Guiding a helicopter to a lost hiker, who was cold, dehydrated and disoriented, by listening for the helicopter's sounds on his connection with the hiker's cellphone and relaying the information to the pilot. • Not knowing for 54 seconds what happened to a deputy calling for backup, and another deputy down, because of poor radio reception. • Soothing a caller whose teenage nephew went to a haunted house and slapped a dummy, which turned out to be real and beat up the kid. Danz earns about $240 a week, before taxes, and while the money isn't much, the fulfillment is. "It's never the same, one day to the next," he says. "It's also very satisfying to have a dangerous situation and have everybody come out safe and nobody hurt." Moonlighting is an occasional feature about Arizonans with cool second jobs. If you qualify, or know someone who does, call Janie Magruder at (602) 444-8998 or e-mail janie.magruder@arizonarepublic.com.
[source: socalscan/Smokey Behr] How to stop a train in an emergency Here's some information that I thought I'd share with everyone, since we had an incident here in Ventura County, CA that ended up on a hot rail. A pickup and a sedan collided, with 3 patients, 1 critical airlifted out. This section of track owned by the Union Pacific Railroad, has Metrolink, the Amtrak Surfliner, the Coast Starlight, and UP Freight on it. They were lucky that they got the Metrolink stopped in time, since the track speed in that area is 79 MPH. As a railfan, I understand the workings of the railroads, and how they like things done. As a firefighter, I know that making sure the victims and rescuers are as safe as possible during any incident. This comes from the General Code of Operating Rules (GCOR), which is a common set of rules that all railroads must follow. The BNSF publishes a .PDF and .PDB version of the rules, so you can read them online. Additional information comes from a lecture by Ernie Sirotek, Jr., Chemical Transportation Safety Manager for the UPRR out of Oakland, CA. -------------------------------------------------------------------- #1: Immediately call the railroad's operation center and inform them that you have an incident on the tracks. Give them a mile post number, block name or crossing name. Crossings have milepost numbers and contact numbers painted or attached to them. Tell them that you are sending flagmen out to protect the incident. #2: Send a firefighter or LEO out 2 miles in each direction from the incident. Make sure they have a minimum of 6 fusees, a red flag (if possible) and a method of communicating with personnel at the incident. #3: Have the FF/LEO (now called a flagman) drop a lit fusee in the center of the tracks at their location, and keep a fusee lit for the duration of the incident. A lit fusee in the gauge is an indication for any train to stop immediately. #4: The flagman needs to stand 6' from the tracks on the left side of the tracks with back to the incident watching for trains. When the flagman sees an approaching train, he needs to begin waving his outstretched arm or flag from above his head to his side in a 180 degree arc. This signal should be continued until it is acknowledged by 2 short blasts of the whistle, or by verbal confirmation with the engineer. GCOR 5.3.5 states that an engineer must obtain a thorough explanation from the flagman before proceeding through a stop signal. GCOR 5.4.7 states that a train must not pass a red light or red flag placed in the gauge until "removed by an employee of the class that placed it", which generally means the person who placed it. #5: When the incident has cleared from the tracks, inform the railroad's operations center that you have cleared the area. If there is damage to the tracks, ties or roadbed, inform them so they can send out a crew to repair the damage. If the damage to the tracks is severe enough to cause damage to the rail equipment, inform them so that they can move the trains away from the damaged section until a crew can be brought in. This includes spread or pinched gauge, bent rail, rail pushed out of parallel, damaged crown (top load-bearing surface) of the rail, or more than 3 damaged ties in a row. I hope this helps those of you that have tracks going through your response area. Sunday, June 10, 2001
[source: socalscan] Sheriff's Department, CHP will share station Los Angeles County Sheriff Lee Baca presided over a ceremony Friday announcing an agreement between the Walnut/Diamond Bar Sheriff's Station and the California Highway Patrol that should result in faster response times and greater law enforcement presence on the area's highways. Twenty CHP officers and two sergeants will now be stationed in Walnut instead of in the CHP office in Santa Fe Springs. "There will be a quicker turnover between shifts, because now they don't have to roll from Santa Fe Springs," Sheriff's Sgt. Tyrrell White said. In heavy traffic, the drive can take as much as 45 minutes. Many of the CHP officers live in the Walnut area anyway, so now they don't have to face a long commute to work just to drive back into their own neighborhoods for patrol. "They can't be happier about it," White said. The Walnut/Diamond Bar area has a relatively low crime rate, but the confluence of freeways, including Interstate 10 and the 60 and 57 freeways, makes CHP presence essential, White said. "This will significantly increase the visibility of law enforcement in this area," White said. |
