EMC_PSTC Listmembers: A couple of weeks ago, I read a post which described a rural OATS that sounded like such a nice place to work. That got me to thinking about all the exotic (don't go past the minefield sign) and dumb (hanging out over a cliff to probe a microwave beampath) or even dangerous (hey you, izzat stuff worth uh lotta cash) places where I have erected an antenna. And that led to my querying our group about their test sites. So, without further blather, here's the honor list (some names deleted to protect the embarrassed).
1.) Steve Kuiper <[email protected]> Our laboratory facility is located deep within a canyon at the base of a 4000 foot mountain in Southern California near a creek bed. The floor noise is excellent and the ambients are low. Line noise is non-existent. Our customers see many advantages. 2.) Jack Cook <[email protected] > Xerox has an OATS in "Rattlesnake Canyon" (a small side-canyon of Bautista Canyon), also in Southern California. Rattlers have been found on or under stair steps, next to parked cars and in other neat spots. Needless to say, the personnel don't walk or stick their hands where they can't look first. 3.) Dan Mitchell <[email protected]> On a loading dock at the rear of our factory. 4.) Derek <[email protected]> My wild life is just the plain old stuff: 9 Deer Squirrels galore A single ground hog 2 chipmunk families A Raccoon At least one owl, And brown bats.... not many mossies this year! The Deer often watch me at night now, kind of strange when you see their eyes in the trees looking at you. 5.) Deborah Olson <[email protected]> I've got a candidate for a test site in the stupidest location. When I worked for a small company in S. Florida we used a test house for FCC Part 15 that was located in a commercial warehouse/office complex adjacent to the Tamiami airport. Behind the complex was the transmitting tower for one of the local TV stations. Also on (or adjacent to) the airport property was a field that was a popular spot for people to fly their remote controlled airplanes. The "test room", if you can call it that, was like an oversized garage bay constructed of a concrete slab, concrete block walls and and metal roof. They did have a piece of copper screening down on the floor underneath the turntable and they also tried to install cones on the walls but they only had enough cones to do part of one wall. When you looked at a baseline scan the noise was so bad that virtually anything could pass. In fact my previous employer got a product approved there that wound up being tested at another lab and was found to be over 20dB above the Class A limit. The site was so noisy that you had all sorts of ambient frequency spikes that could (and did) "hide" a failing frequency emitted by the equipment under test. I asked the technician one time how in the world the FCC approved their site and he replied that the site wasn't approved for formal scans---just pre-testing. The "formally approved" site was an OATS in the owner's back yard who lived in a rural area. But it was too far away for customers to go to so they just did everything from the warehouse location. The owner was supposedly had friends ... so he wasn't worried. I suspect that they're no longer in business. 6.) Randall Flinders <[email protected]> We have an open area test site in our Competitor's Parking Lot. Located in Downtown Costa Mesa, I sometimes wonder if I am getting cancer from all of the ambient signals! 7.) Larry Stillings <[email protected]> President, Compliance Worldwide, Inc. We have a 3 / 10 meter OATS off the garage of my house in Central NH. Product and personnel enclosed, 3 & 10 meter antennas outside. Very low ambient. Check it out at http://www.cw-inc.com 8.) Eric Henning <[email protected]> "...is laboring away in the underground hallway where I do pre-scans..." 9.) Terry J. Meck <[email protected]> I was able to conjole a 6m x 6m room next to a shipping dock in the back of one of our buildings. Facing a woods. I was also able to talk them into a galvanized sheet metal ground plane. This same building had, in the shed outback a bird littered 10' x 10' screen room we stumbled on when we took possession. It helps a little for small products and creating a suspect list. It is still very full of time consuming ambient signals. But it could be worse. I used my back yard a few times when I first got into this. Saturday AM before 9 was a good time. That seems a long time ago. 10.) Gary McInturff <[email protected]> The actual OATS test arena was non-descript. It was open on flat ground outside of Spokane WA. Ground cloth was down and the perimeter was bonded to copper ground rods. The Test Equipment hut from which the test was performed was a choice of convenience. There happened to be a tin building sitting over an abandoned well head. The building was about 6 X 6 with a cement floor. The walls and ceiling were covered with corrugated tin attached to open 2 X 4's. The roof support 2 X 4's rested on top of the walls and atop that was the roof tin. Between them was the "air conditioning system" the gap between walls and tin roof. A single 100 Watt light bulb that illuminated the inside doubled as the heat source. Spring and fall weren't too bad but summer and winter in Spokane can get extremes of a week over 100 and a week below zero. The rest of the year is somewhere between 80 and 30. In the winter the equipment, including the $80,000 analyzer, was transported to the test hut via a tractor that normally was used to remove snow from the facilities. When we got to the hut before we could set the analyzer up we had to knock the snow off of the setup table. By the end of the day the snow that was knocked onto the floor had yet to begin to melt! In order to walk to the restroom it was a three block walk through sometimes knee-deep snow. (Yellow snow, I might add, is visible for a long way!) Winter was eventually survived and spring enjoyed. Then summer hit. We became painfully aware why some countries put POW's into tin sheds for punishment! Shorts, no tee shirt and sweat bands were an absolute must. Occasionally, I had meetings which I had to attend. I was fairly visible amongst the tie wearing set! During much of the year many of our engineers flew radio controlled airplanes in the area. They like to buzz the test hut and on one occasion committed a plane to a suicide run into the hut. Scaring the (*)#($*)#(*$ out of me. What they failed to recognize was that I could identify which frequency they were flying on and I had both an antenna and a frequency generator. Planes began falling out of the sky! I thought I had made my point and won the war - but they were patient! Come the very next winter I was in the igloo when they crept up around the hut, locked the door from the outside and began flinging snow into the shed through the gaps between walls and ceiling. I literally had over a foot of snow all around me when they got done. In order to remain anonymous they didn't even unlock the door. The called security and sent them. 11.) Douglas McKean <[email protected]> The most er ... challanging site where I had products tested was at an OATS run by Xxxxxx when they were just on the other side of the fence (literally) from Manchester Airport in Manchester New Hampshire. I think they've moved. 12.) Douglas McKean <[email protected]> Another one was in New Hartford CT run by a single gentleman. It was in his barn. If you left your product out on the table over night, you had to scrape a ton of bat shit off it the next morning ... 13.) [email protected], in a previous life at an unacknowledged facility "Here boy, take this gas-mask kit and keep it with you night and day. Put it on right quick if you hear the warning siren!" says the Sargent. "But we'll be out on the desert floor, miles from the base. What if we can't hear the siren?" says I. "Well, you got a big group of people with you. Just stay on the downwind edge of the group. You put your mask on when the other people start to drop." instructs the Sargent. "Now this here's your Atropine antidote self-injector. If you notice your vision starting to narrow down to just a little spot, then slap this end down right smart on your thigh." he continues. "Uh Sargent, what if we only get a little exposure, but the injector delivers a full shot of antidote. What happens if we get too much antidote?" I wonder. "Shaddup!" he suggests, very convincingly. 14.) [email protected], in a previous life at a non-existant facility "I don't care if you ARE a civilian contractor, I'm getting a blood sample from you NOW and when we let you off the base." said the very intimidating civilian whatever. "They been making and testing nerve gas here for 45 years, but they still spray bug-killer each night?" 15.) [email protected], in a previous life at an unacknowledged facility "It costs 8 six-packs for me to let you drive that M-113 (turbine powered, tracked, armored personel carrier; thank you, America!)." 16.) [email protected], in a previous life at an unacknowledged facility "I wonder where all the rattlesnakes go during the heat of the day." 17.) [email protected] At China Lake, in the high Mojave Desert, the burros come out at night and chew the vehicle tires, power cables and coax cables. 18.) Joe Martin <[email protected]> I went to this particular site ONE time. It was right next to San Fransisco International Airport. Ambients. What's an ambient?? "Can you please turn your instrument off and on again." (100th time). 19.) Scott Douglas <[email protected]> I have a room in the corner of our building. No windows, but my own heat and A/C. Two walls are lined with foil faced foam insulation, all seams are copper taped together. I have a 5' x 10' sheet of galvanized steel floating on the center of the floor for a "ground plane". The software lab is to my right and the electrical lab to my backside, thus the foil faced insulation "shielding". The room was previously used as a computer room, raised floor and all. It held the PDP-8 which finally went away in 1995. 20.) [email protected] I have used in the past a site which is owned by Celectica in the UK. The 30m site is located in a cavern in a rock salt mine 600ft underground. 21.) David Brumbaugh <[email protected]> I work for a defense/government contractor, and we don't use an OATS facility here at my location, though we've been known to in the distant past. We mostly test indoors, but when I go to lunch or look out the window, on most days I can see Mt. Rainier standing majestically in the background as I peer south down the Kent (WA) valley. On a really nice day, it's a view that's hard to beat. 22.) Hans Melberg <[email protected]> This is not an existing chamber but my dream someday! I have for years tried to convince someone to give me money to construct, in my opinion, the best (semi)-anechoic chamber. I call it the "Picasso room" because no two walls are parallel. This way, the absorbers which are at the hairy edge of non-functionality are helped along by removing symetric reflections. I believe that I can improve chamber performance (absorber performance really) by at least 6 to 10 dB. The room, would be quite easy to construct as the primary backbone would indeed be a perfect parallelopiped from where to anchor the walls and ceilings. The floor would of course be level. There is more. The room would would utilize multiple antennas and the turntable would turn slowly (1/2rpm) and indefenitely in one direction. A complete scan could be accomplished in less than 2 hours from 30MHz to 10GHz. Output plots would would pick each EUT frequency x-dB above noise floor or y-dB below a limit and plot them for azimuth vs field strength vs elevation. Dreams. Well, that's the whole bunch. First, I'll disqualify my entries, cause if I won anything, I would have to deny all knowledge of everything. So here goes: Top award goes to #22, Hans. What can I say; he's a dreamer of automated data reduction and non-linear geometry. Next mention goes to #1, Steve. I wonder how the fishin' is in that creek? An honorable mention goes to #4, Derek, for his attention to small animals. I didn't think anyone would beat #8, Eric, in his underground hallway, but #20, Chris, beat him by some 600 feet (err, 200 meters). Special mention to #21, Dave; he's got a window! And finally, congratulations to #18, Joe, for locating an OATS without an ambient. Thanks to all for sharing your stories. Ed -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 11/18/1998 Time: 12:16:03 -------------------------- --------- This message is coming from the emc-pstc discussion list. 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