Frank’s Radar Life
A career of measuring radar emissions: More fun than I ever deserved to have...
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Prologue to Radars: The High School Years
Building an 8” Telescope and a Radio Telescope in High School
I have built an entire professional career out of studying radar emissions and related phenomena, first as more of an engineer and now as more of a scientist. It all started when I was in high school in Arvada, Colorado. I was fascinated by a lot of things, and one of them was optics. I wanted to learn both the theory and the application. On hte application side, I worked during my sophomore and junior years to grind and polish my own 8” telescope mirror. It could have gone faster if I’d had anyone around who could show me the best way to do it, but I didn’t have anyone who could help. So I read the books and tried different things as I ground and polished and finally figured the final surface (with a Foucault tester that I built myself). I worked in hot and dry, wet and cold conditions, on a 50-gallon drum filled with water. Sometimes I worked at school in the afternoons, and sometimes at my grandparents’ house (below) where I was living with my brother and sister. I wasn’t brilliant about how I did the work, but I stuck to it until I got it done. We weren’t strictly poor growing up (a lot of people were worse off), but things were always tight--my mother had died when I was seven years old and I was living with my grandparents and siblings on a very limited income. I knew my only hope of succeeding was to work hard and be smart. I believed that honest persistence in the pursuit of knowledge and practical experience would reap its reward, and it did. (Now I’m a GS-15 with the U.S. government, I run the Telecommunications Theory division at my lab, I have an international reputation in radio science, and am proud to be able to cite my publications in diverse fields such as paleontology. I think that a person can make it in America even if they don’t have the hottest start, if they’ll work hard at everything that they do and hang in there when things are tough. And if you screw up, as I did once in college, you can always start over.)
Frank Sanders grinding a telescope mirror in the winter of 1977-78.
On the one hand the work went more slowly than it needed to. But on the other hand, I really learned a lot by sorting out the mirror problems for myself. The best thing of all that I learned was how to learn to analyze and trouble-shoot a new technical system. That’s what many people never learn--how to deconstruct a system (in your mind), work out a problem in the system, and then mentally reconstruct the system again, this time with a solution implemented. Then you try your solution on the real system. The only way to learn the technique is to sort out these kinds of things for oneself. This knowledge and ability doesn’t substitute for hitting the books and getting college degrees, but it does complement such degrees. Apprenticeship helps. Then again, to some extent either you get it or you don’t. Some people never do, but most can learn to do better.
I had a crazy fantasy that some cute girl would want to work on the mirror with me. Boy, was I naive. I mean, what was I thinking? In my class at Arvada I had an interest in several girls in my classes, but was too shy to ever ask any of them for a date or anything. Plus I didn’t really have any money for going out. Kids today often seem to have a lot of money, and they take it for granted. I didn’t. Anyway, looking back, my only high school regret is that I didn’t save some money for some dates and ask some of those girls out. Let that be a lesson to you guys who read this and are now in high school yourselves.
Ah well, onward. As much as I liked my finished optical telescope (I still have it), I wanted to move on and try to pick up cosmic radio signals. That’s the story of my life--as soon as I master one thing, I want to move on and learn another.
Building a Simple Radio Telescope
So in the summer between my junior and senior years in high school I hit the books and studied the theory and design of superheterodyne radio receivers. (Oddly, still no girlfriend at that point.) I’ve never had a bit of interest in ham radio for some reason, but instead I used my new-found knowledge to design and built my own radio telescope that I used to pick up noise from Jupiter, the sun, and the center of our galaxy. It was large and clumsy and didn’t perform all that well, but I could watch the deflection of a voltmeter needle get bigger and bigger as Jupiter or the sun or the galactic center transited the main beam of my telescope (which was fixed-pointed toward due south but could be elevated to match the height of the object above the horizon when it was due south of me). Then I saw the needle deflection gradually get smaller and small as the object continued to the west. I thought that was fantastic! Still no cute girl, though, for some reason. Oh, well.
Junior Fellow Years at a Government Lab
Eventually one of the teachers at my high school mentioned a Junior Fellow program for college students that the National Bureau Standards (now NIST) lab had in nearby Boulder. I applied for three jobs under that program. Of the three, one did not interest me. Of the other two, another guy was selected for the one that I thought I wanted the most. But I was selected for the third opening, one that I thought looked OK but that did not look as intriguing as the one that I had my eye on.
Nevertheless, I took the Junior Fellow position that I was offered, and it changed my life forever. I took the job just before I graduated from high school, in May 1979. Twenty-eight years later, I’m still there, at the U.S. Department of Commerce Institute for Telecommunication Sciences (ITS) in the National Telecommunications and Information Administration (NTIA). I started as a GS-nothing and am now a GS-15 (aka Band V) who heads the ITS laboratory’s Telecommunications Theory Division.
Frank Sanders as a high school senior, fall 1978.
My Introduction to the Government’s Radio Spectrum Measurement System
The job involved something that I had never thought about in my life, namely radio spectrum management and engineering. It sounds boring, but the work that we were doing in the Radio Spectrum Occupancy Group (RSOG) was anything but. It turned out that the Department of Commerce, as the overall spectrum manager for all U.S. government radios and radars, had developed a computer-controlled spectrum measurement system called the ARS-400 as a joint effort with the Helwett Packard company. This system was the world’s first computer-controlled, programmable spectrum analyzer. It was mobile, mounted in a Dodge Travco motor home. It occupied five full-height 19”-wide racks of electronic equipment. The system ran from power delivered either from commercial lines (shore power) or from a pair of on-board (later a single) on-board generator. Two air conditioners were mounted on the roof, eventually. There was a 30-foot high rigid antenna mast that was raised and lowered with a motor-driven screw jack. It was so cool, like something out of a movie.
So here I was, a kid fresh out of high school hired by these government guys on the basis of nothing more than my high school record. I didn’t know anything about anything; I had to learn everything from the ground up, about how the measurement system worked, about how to do field measurements, and so forth. All I could really bring to the table was some portion of brains and a strong willingness to work and to learn new things.
They treated me incredibly well. The group leader, Bob Matheson, was a really smart guy with a great sense of humor. I’m still working with him now, in his retirement, all these years later. John Smilley was the charismatic engineer who specialized in measuring emissions from radars. Gary Gierhart was the slightly nerdy-seeming engineer who knew the land mobile radio measurement system inside and out. Vince Lawrence was the technician who helped hold the whole thing together, who collated all the data, and who meticulously and thoroughly worked on our group’s reports. I learned hugely from every single one of those guys, and it’s a debt that I’m still repaying in a way all these years later.
Early Radar Measurements
I began to work especially closely with John on the radar measurements. This turned out to be about the coolest thing to do in the world. Our job was to obtain detailed emission spectra on pretty much every radar type in the U.S. inventory, from boat radars to giant space-search and space tracking radars. We took the Travco out on the road starting in June 1979 and became radar vagabonds, traveling from one radar site to another across the United States, sometimes for weeks on end. The system was called the Radio Spectrum Measurement System (RSMS). It excited interest wherever it went, because it looked so weirdly exotic. When it was rolling down the road it had this bulky aspect that was dominated by the rigid lattice-work mast lying on its side on the roof of the van, with three giant-size cones on the mast pointing skyward and a fourth giant cone pointing rearward from its mount on the back of the van. (The cones were wide-band land mobile radio antennas that operated in the VHF and UHF parts of the spectrum. We didn’t operate them from those positions; that was just the way we mounted them for road travel.)
Nowadays everyone is used to electronic news gathering trucks on the highways, but in 1979 nobody had ever seen anything like this. And the fact that painted “U.S. Department of Commerce Institute for Telecommunication Sciences Boulder Colorado” on the sides of the van didn’t help. Everybody thought that was just a cover for something else.
“Our presence here has nothing to do with recent UFO sightings”
For example, one time when we were working at Edwards Air Force Base in the southern California desert, we pulled into a gas station just as the sun was setting. Everything looked like a scene in a movie--the lonely, deserted gas station, a tumbleweed blowing across the asphalt, the sun setting. Fueling the van took a long time because it had two fuel tanks and they didn’t burp air very effectively as the gas went in. So as were sitting there watching the cactus grow, we noticed two guys inside the station office who were obviously talking about us, pointing at the Travco through the window. Finally, one of them came out and walked over to us. He started making some small talk, asking about Boulder and so forth. Finally, it became clear that he was dying to see what was inside. So John Smilley said, “well, here, have a look.” John took the padlock off the door (we had to padlock it because the regular latch was unreliable and we didn’t want the door flying open on the road). When the guy looked inside he saw all these hugs racks filled with exotic-looking electronic equipment: oscilloscopes, computers, analog-to-digital and digital-to-analog converters, electronic screen monitors, you name it.
The guy pulled his head back out of the van and turned to John and asked, “you’re with the Department of Commerce? And John answered, “well, I just want to make it clear that our presence here has nothing to do with the recent string of UFO sightings that have occurred in this area.”
The guys eyes got big and looked at John without saying another word, the unspoken message being, “Gotcha, big guy, I understand.” Then he turned around and hurried back to the gas station office. Just as he stepped inside with the door swung shut behind him we heard him say, “Charlie, I told ya!”
The Growing Years of Radar Measurements
The radar emission spectrum project effort was a big success. I joined it in 1979, just as it was really gathering steam. We gathered a huge amount of data on emissions from nearly every type of radar in the U.S. inventory. For each radar, we gathered emission spectra and all other pertinent emission characteristics. We traveled for weeks at a time with the RSMS, moving from one radar location to the next. We became very efficient at getting the RSMS into position near a radar antenna (usually about 0.3 to 0.7 miles away from the radar), setting up the measurement system, getting it calibrated, and then starting the radar measurement. As for the radars themselves, the operators were usually worried that they would have to do something special to their radars, to alter their operations for our measurements. But we always insisted that they just operate the radars normally--we did the rest.
We developed a special measurement technique that allowed us to quickly and accurately obtain all the emission characteristics of a radar, including its emission spectrum, without needing any access to the radar itself--we worked out how to get everything from a distance.
We measured emission spectra of airborne radars, naval radars, meteorological radars, air traffic control radars, little radars on boats and giant space-search radars--you name it, we shot it in those years. I’ve subsequently kept up with newer radar types. It has been a great adventure, always a lot of fun.
I know how to do a lot of things merely well, but I dare say that I’m either the top expert in the world on the topic of measuring radar emissions, or at least one of the top three or four. Admittedly it’s a niche market, but it’s important that we know how to measure these emissions. Using our special technique, we can measure a radar emission spectrum with at least 100 dB or dynamic range, and usually with 110-120 dB of dynamic range. That’s as good as or better than anyone anywhere can do. I can look at a radar spectrum and immediately tell what the transmitter output device probably is (magnetron, crossed-field amplifier, klystron, etc.). I can watch the radar emissions in the time domain for a few seconds, noting pulse width, pulse repetition rate, stagger (if any), frequency hopping and diversity behavior (if any), pulse repetition interval(s), and then tell you almost exactly how the radar works, what its functions are, and what its maximum range will be. It’s so much fun to do that, I’d rather --not-- know anything about a radar before I measure it. It’s more fun to work it all out for myself, without any briefings.
If you want to learn most of my radar secrets (I’ll always keep a few up my sleeve), go to the ITS web site at at http://www.its.bldrdoc.gov/pub/pubs.php and download, from our publications page, the NTIA Technical Report 05-420, “Measurement Procedures for the Radar Spectrum Engineering Criteria”. You’ll need fortitude to get through it, but there it is. If we had classified that document, people would have gone to great lengths to get the information. When it’s available for public download, people yawn.
Learning to Solve Problems...
What I really learned how to do in these early years of the 1980s was to solve problems. Every job we did was an intricate mixture of political contacts, administrative work, and technical problem solving. Every job was different. We had to assess every situation individually and use all of our knowledge and experience from past efforts to solve the newest problem.
We never failed to get the job done. In fact, our motto was “whatever it takes to get the job done.” Sometimes the problem was to obtain access to a system or a location. Sometimes the problem was to get the system calibrated. Sometimes the problem was that the radar (or whatever we might be measuring) was being difficult. But we always figured out a way to get the emissions measured. We always maintained a tight focus on our goal, whatever it might be, and always kept pushing toward that goal no matter what difficulties might be placed in our way. We were persistent.
...and Learning to Not Jump to Conclusions
It was also in these years that I learned that people all too often jump to conclusions about why radio systems (or at least systems that utilize radios for communication links) fail. We discovered that, more often than not, reports of radio interference actually were rooted in non-radio-interference causes. In other words, most reported radio interference wasn’t--it was some other system failure. But when someone is faced with a weird system failure, it may seem to be easier to point the finger at the radio link than it is to really troubleshoot the problem. So we became very good, in those years, at sizing up an entire system quickly and working out the possible failure modes of everything in the system in question, and not just the radio link part of it. I’ve used that experience for the rest of my life.
Not jumping to conclusions is a lesson that has to be learned, and is not innate, I think, because human beings are naturally predisposed to observe patterns and extrapolate from them without any additional evidence--which is jumping to a conclusion about something. It can seem to be a very cut-and-dried approach. Often, that approach is very useful. It is so useful that it conferred a survival advantage on our ancestors and became part of our genetic and cultural heritage. But it can be a terribly pointless, useless, misleading and even dangerous approach to understanding the world when the stakes are high. I think we have now learned that lesson to our sorrow in the Middle East.
By the way, even in cases in which we have found radio interference to be occurring, the cause is more often poor receiver design (specifically receivers lacking adequate front-end RF bandpass filtering) than transmitters operating on the wrong frequency or causing interference due to spurious emissions or other mechanisms.
The Later Years
Nowadays I’m the head of the Telecommunications Theory Division at ITS in Boulder. I try to manage with a light touch. Everyone in my group is experienced and smart. They know what their jobs are. I wouldn’t be so stupid as to try to over-manage or micro-manage them. If they have a problem or need official approvals, I take care of it. Otherwise, they have their work to do and I have my work to do. Get after it and get it done, I say. You don’t need me to tell you how to do your work.
In recent years I’ve branched out into a whole new area of research: The effects of interference on radio receivers. (Although I still do the radar work as needed.) We have embarked on a multi-year effort in this area. Several other guys in my group and in the Office of Spectrum Management (ODSM) in Washington are working on this together. We need to work on this now because new spectrum management paradigms are all stressing spectrum-sharing between system. In effect, they are supposed to depend upon spectrum management on an interference-limited basis. But we don’t as much about interference effects as we should.
Our most recent report in this area is available on the ITS web site’s publications link at http://www.its.bldrdoc.gov/pub/pubs.php, downloadable as NTIA Technical Report TR-06-444, “Effects of Interference on Radar Receivers”. Download it from the ITS web page to learn more, or if you want to get some sleep.
This won’t be the first or the last time that I’ve picked up a new research interest. We’ll run this out for years to come, until we think that we’ve adequately explored the problem for the time being, and then it will be on to our next adventure. I have so much fun in my life, it’s obscene!!
Original RSMS 1927
Frank Sanders scouting a desert radio measurement site
Frank with suitcase measurement system
Frank going up a radar station antenna without his climbing belt--big No-No!
Frank Sanders riding a radar antenna (not radiating)
Frank Sanders inside a big radar
Frank Sanders calibrating a radar phased array, courtesy USAF
Preparing a suitcase measurement system
Frank repairing a generator during a desert exercise
Radar phased array being calibrated by Frank, courtesy USAF
RSMS-IV software developers
radar rotodome
Airborne radar suitcase measurement
Airborne radar measurement
Roof View National Cathedral
National Cathedral rooftop
Rooftop spectrum survey in progress
Low-profile suitcase measurement system
RSMS-III interior view
RSMS-II radar measurement system
RSMS-I radar measurement system
RSMS-I land mobile radio (LMR) system
RSMS-II LMR measurement system
RSMS original radar direction finding system
Early RSMS development system
RSMS-III with dish antenna
RSMS-III on landing craft: we go anywhere
RSMS-I with TPS-43 radar
RSMS w TPS-32 radar
Travco RSMS-I at sunset
RSMS-III with flag near Love Point
Airport surveillance radar (ASR) with RSMS-III
RSMS-III on tactical desert operation
Fire control sign with RSMS-IV
RSMS-I with F-105 Thunderchief (Thud)
Airborne radar, courtesy NASA
RSMS-III spectrum survey above Los Angeles
RSMS-III at a TDRSS ground station
RSMS-III at Point Loma San Diego
RSMS-III Flatirons
RSMS-II Travco
Goldstone dish with RSMS-I
RSMS-I desert
RSMS in winter location
RSMS-I at Helendale
RSMS w ASR-5 radar
RSMS w TPS-43 radar
RSMS at the big Stanford dish
RSMS at sunset
RSMS snowed-in at Sunspot NM
RSMS-1 survey mode
RSMS John Smilley
RSMS Bob Matheson
RSMS Gary Gierhart
RSMS Vince Lawrence
RSMS-I radar meas in progress
RSMS-I staff 1970s
H-60 Blackhawk deployment chopper for one of our suitcase monitoring systems
Suitcase monitoring system on an H-60 Blackhawk chopper
Jumping out of our chopper for a desert deployment
H-60 Blackhawk chopper departing one of our mountaintop sites
Desert hummer-based radio measurement system
RSMS-III desert camp
RSMS interior during desert ops
RSMS-III during desert exercise
US Army tank crew surprised to see us
Desert interference troubleshooting
Nexrad radome closeup
Air search radar antenna
ARSR-3 radar with measurement equipment
ARSR-4 radar feed
ARSR-4 radar feed seen from top of antenna
Air traffic control radar interference testing
Setting up a maritime radar in Colorado
Setting up another maritime radar on a prairie
X-band radar display
Naval radar array, courtesy USN
This is what I’ll surely see when I arrive in Radar Heaven.
