Well . . . from what I read so far . . .I think Ed's experience ranks right 'up there'! (Pun intended!) Seriously though . . . I think we've got a winner there!
John A. Juhasz Product Qualification & Compliance Engr. Fiber Options, Inc. 80 Orville Dr. Suite 102 Bohemia, NY 11716 USA Tel: 516-567-8320 ext. 24 Fax: 516-567-8322 -----Original Message----- From: ed.pr...@cubic.com [mailto:ed.pr...@cubic.com] Sent: Thursday, March 11, 1999 11:22 AM To: EMC-PSTC Subject: Re: Awards for Worst EMC/PS qualities > Subject: Awards for Worst EMC/PS qualities > Author: <b...@namg.us.anritsu.com> (Bailin Ma) at Internet > Date: 03/08/1999 8:03 AM > Hi Group, > > We have already seen awards for the most misleading ads, worst attire, > worst films, ..... > Why not awards for worst EMC and PS qualities? > > Barry Ma > Morgan Hill, CA 95037 OK, I'll submit my entry for both the EMC and PS categories! Years ago, whilst working at a large defense contractor, we re-built 5 UH-1 Huey helicopters to act as test beds for a large synthetic aperture radar system. All major mechanical and electrical systems were stripped out and then replaced (at the mid-point of the job, the Hueys looked like a wire-frame model). When we got everything back together, we had to go through flight worthiness testing. After that, we installed the electronics racks and started a set of platform EMC integration tests. So, I found myself hovering for hours at about 500 feet, while we ran through various operational modes of both the electronics payload and the vehicle systems. Everything checked out fine, until we found an accidental, uhhh, feature. Suddenly, just like an elevator to heaven, we started to climb straight up. I mean wide open throttle and full positive collective pitch! Well, I don't know how fast a heavily loaded Huey can climb, but it was impressive! I don't even want to think about how far those rotors deflected. After the pilot got things stabilized, and we all started breathing again, we started to sort things out. The problem turned out to be that the pilot had his autopilot engaged (I didn't know Hueys even had one), and then decided to key the UHF radio. We found that, out of twenty thousand or so UHF channels, about a dozen would cause the Vertical Speed Indicator to deflect full negative when the radio was keyed. And that instrument told the autopilot that the Huey was going down, so the autopilot cranked in as much pitch correction as possible, and also opened to full throttle. The result was; key radio on a "magic" channel and you get a penthouse express. (Actually, not too bad a result, considering what the result would have been if the VSI had been deflected full POSITIVE!) After a little snooping, we found that the VSI cable harness had an improperly assembled backshell, which degraded the shielding effectiveness of that cable and allowed RF into the indicator. Ed -------------------------- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 03/11/1999 Time: 08:21:48 -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
