Tour De Force Of Table Mountain Facilities
By Suzanne Webel
On August 25, the Table Mountain Association Board of Directors was treated to a full afternoon tour of various scientific facilities on the top of the mesa, hosted by officials with the Department of Commerce and USGS. Come take the virtual tour again with us from the comfort of your armchair.
A round of introductions at Jo Ann and Jim Mays' home on Plateau Road provided a nice overview of activities on the mountain. Rick Johnson, Building Management Specialist with the Mountain Administrative Support Center, invited a dozen specialists who came to share information about their projects. The introductions led to several interactive discussions of some of the activity observed by TMA members this spring.
For example, Patrick Disterhuft, who works with the National Oceanic and Atmospheric Administration (NOAA), recounted his decision to replace the 30-year-old copper telephone lines on the mesa with more reliable fiber-optic cable. Initial bids for the work were beyond the budget of all the groups combined, so he enlisted the services of the Army Reserves, which trenched the lines in for free on weekends and gave the reservists, who are the mostly college students, an opportunity to learn how to operate heavy equipment. Sunflowers, which thrive in disturbed soil, now mark the location of the new buried cables.
Dr. Disterhuft’s projects include the measurement of ozone events in polar regions (which is important because decreases in the global ozone layer can lead to increases in cancer). He also described the use of relatively low-level lasers projected from a building near the southwest corner of the mesa to targets on the ground about 1000 feet away, which are used to measure atmospheric conditions (the lasers are never turned on unless personnel are present to monitor safety).
Mark Randolf with the National Institute for Standards and Technology (NIST) police staff monitors all Department of Commerce facilities, including Table Mountain, which is closed to public access. He stated that no weapons of any kind are allowed on the mesa, and the former shooting range is now closed. The NIST police are connected to Boulder Regional Dispatch, and he urged neighbors to call 911 and report any problems observed.
William Kissick from the Institute for Telecommunication Sciences (ITS) discussed the in-line array of 26 wooden towers on the west side of the mesa. These are not used any more and most could be demolished if people found them to be objectionable (we were generally supportive of getting rid of unused materiel on the mountain).
Terri Maraia, who works for NOAA, presented an outline of the radio quiet zone at Table Mountain, one of only two in the United States. She said that since 1973 the FCC has required broadcasters to lower the strength of their signals over the mountain, and asked if we had any reception problems (most of us did not report any). She emphasized that all facilities on the mesa are "receive-only" – specifically, they do not transmit any electronic waves or broadcasts of any kind, and don't actively interfere with our own electronic devices. She indicated that cell phones, ham radio, microwave ovens, electric fences and garage door openers are OK, and will write a waiver for people who ask to install these devices if one is required.
Kevin Shoemaker is a director of the volunteer group that operates the large dishes, but spent much of the introductory session discussing aircraft flyovers since he is also a flight instructor at Vance Brand Airport in Longmont. He advised us that, according to FAA regulations, planes are not supposed to fly at heights less than 1000 feet in populated areas, but there is no clear definition of what constitutes a populated area. He suggested if people have a problem with low flights we should contact the FAA in Denver; he is willing to become involved personally with our situation and suggested that we contact him for help (call TMA aircraft committee person Steve Trachinger at 303-440-6953).
Kent Groninger, the Executive Director of NOAA's Labs in Boulder, indicated that they will be constructing a national open-air test site to calibrate antennas. He volunteered the information that the Federal Government has no plans to divest itself of this property.
After these introductions, we caravanned eastward up the extension of Plateau Road to the first stop, a small lab where Dan Winester of the NOAA Geodetic Survey showed us his setup for measuring gravity. There is a continuous GPS antenna to measure the exact location and altitude, and his facility is the main calibration station for many standard gravimeters. These devices can measure earth tides, which fluctuate as much as 3 feet per day, and can determine sea level changes around the world.
Our next stop was a visit to the lab of Jim Abeyta, a computer specialist with the NOAA Space Environment Center. Three medium-sized antennas track the Geostationary Observational Earth Satellite (GOES), which downloads the real-time weather pictures that you see on the evening news. They also obtain early-warning data from weather satellites about changes in X-ray, proton, electron, and magnetic fields between the earth and the sun, which can protect satellites, astronauts, and power grids from destructive particle bursts and magnetic disturbances. His building was one of the original sites for Cold War data gathering in the 1960's, but he emphasized that nobody up on the mesa is involved in that kind of activity any more.
Leo Panratz, a geophysicist with the United States Geological Survey (USGS), gave a presentation of the earth's magnetic field, which is measured continuously from an unattended lab on the mesa. Their equipment detects changes in sunspots and solar flares, and can be used to protect expensive satellites and prevent power surges. He showed us some classic magnetometers as well, which were small brass devices with handmade gold and quartz fibers and mirrors. His equipment is so sensitive that he requested we park our vehicles 200 yards away so we wouldn't disturb his measurements.
Our final stop was at the two large dish antennas on the northeast corner of the mountain. They were constructed in the 1940's by a screen-door company, of all things, for tropospheric scattering experiments. They are 60 feet in diameter and can withstand 200 mph winds. The open mesh design of the dish (yes, their surface is not solid) limits frequencies but makes them lighter and allows strong winds to pass through. The dishes had been idle for 10 years until 1991, and have gradually been reactivated by an independent non-profit organization called the Deep Space Exploration Society (DSES). Its president, Amanda Cox, explained that they are a group of hobbyists who love space and science in general, and use the antennas for educational purposes.
Much the DSES equipment is donated, such as a diesel generator, which is used to power the motors that move the dishes; they cannibalized a third dish in southeastern Colorado for spare parts or make their own. The command and control software that operates the dishes was written by CU computer science students, one of whom explained the program. They track quasars, pulsars, satellites, the space shuttle and Mir, and look at the Milky Way. The lower dish is not yet functional, but a family of white owls has decided to call it home and nests there every year.
By the end of the tour, there were about 24 people who were all eagerly asking questions and learning from each other. Many of the participants routinely conduct their own official experiments on the mesa in complete isolation from each other, so they appeared delighted to have the opportunity to learn what the other people in the little buildings down the road actually do in there. And for us, the neighbors of the facility, it was a unique opportunity to learn more about the people as well as the projects that are undertaken up on the mesa. I was personally gratified that it was one of the central tenets of the mission statement of the Table Mountain Association – "to work to develop a cooperative relationship with the management of Table Mountain" – which brought us all together.
The mesa is just about completely flat on top, with boulders and gravel strewn everywhere. With the exception of a sparse grove of cottonwoods at the north end, the tallest vegetation around appeared to be the sunflowers. Despite rumors to the contrary, I saw only a few scattered knapweed plants (I plucked one and showed it to the group, most of whom had heard of this noxious weed but had no idea what it looked like). Apparently there is also a small infestation of Mediterranean Sage, another noxious weed that will be sprayed this fall using hand-held sprayers only.
There is a network of gravel roads connecting the small, rather desolate buildings, abandoned trailers and antennas, old bunkers and debris from the Cold War era, which are scattered everywhere and present a danger for unwary trespassers. But the views from the top are fantastic in all directions!