Frosty and I went to Turkey to do a little shielding work. “Travels with Frosty,” coming at you.
We rendez-vous’d at the United Counter, Frosty sporting his signature cowboy boots and white T-shirt, a ponytail-in-progress sprouting from under his hat and a brand-new girlfriend on his arm. We were heading to Eastern Turkey to do some shield tests at a link in the ring of passive listening and defense girding the soon-to-be defunct Soviet Union. But she and he were clearly enamored, having met just two weeks before.
So I walked away and said “See you at the gate?” as they massaged their good-byes.
Frosty got on-board the aircraft at the last minute and settled into his seat, pulling his boots off and flexing his sock-less feet. “Man. I can’t wait ‘til this gig is over,” sighing, “She’s a jewel.” He leaned back as the engines throttled up and we started rolling. “Maybe I’ll bring her back something special,” he murmured. The 747 rotated, pitched up and nosed east.
And eighteen hours later, via Paris, we were terra firma on the dividing line between East and West at Esenboğa “Healthy Bull” International Airport, 20 miles north of Ankara, resting on the breast of Turkey (Turkiye).
Our host Ibrahim, a tall, laconic lean forty-something mechanical engineer with an alley-wear five o’clock shadow, met us at the airport. We bounced into Ankara (I would go back anytime) in a boxy sedan. Ibrahim, we found, had a rather droll sense of humor. We would appreciate it.
The capital Ankara, née Angora, wears leafy streets and a hilly personality: a city upon a hill steeped richly in history. Not far from the womb of western civilization, one stumbles across the encyclopedia of the Ancients: Greek, Persian, Roman, Byzantine, Persian and Galatian (of St. Paul’s Letters fame). We’d spend one night here and the next day head further East to the city of Diyarbakir, in the northern reaches of Kurdistan and not far from Mount Ararat, near the bones of Noah’s Ark.
We were grateful to find a quiet bed after a long flight from Washington. Before we turned in, Frosty and I had a few cold ones “just to help us sleep” and went over the test plan for the facility. It was a standard test and was required before the facility was commissioned (and the contractor could get paid). The all-welded room had been designed to protect the listening equipment from outside eavesdropping and from unthinkable EMP. We made a list of test points and test frequencies: magnetic field test from 10kHz and E-field measurements up to 1 GHz.
Frosty jabbered on about his new darling. “We met last weekend. It’s been great ever since.” He winked at the young waitress. “Merhaba,” she said, smiling coyly.
“Yeah, I can see you miss her.” I said. Frosty laughed, snorting into his beer.
A few winks later and we were awoken by a call from the front desk from Ibrahim, now joined by his colleague, Mustafa, compact and fierce-looking, foil to the cool Ibrahim. We re-packed quickly and checked out of the fine digs of the Ankara Oğultürk Hotel, the front desk monitored by a prominent portrait of Mr. Atatürk, the founder of modern Turkey.
Atatürk’s likeness was everywhere: in government offices, banks, hotels, offices and private residences. His career gained momentum after the British withdrawal from Gallipoli during World War I, when Turkey was known as The Ottoman Empire and Istanbul was known as Constantinople. (We’d get to spend an eventful night or two in Istanbul at the end of this trip, but we still had our real work to do.) By the early 1920s, Atatürk was re-casting Turkey as a modern, democratic, secular country. Turkey has been a long ally of the US, an important bulwark and interesting mingling of East and West.
The four of us crammed into a taxi and we chatted about the project and engineering business in Turkey as we headed to the domestic airport at Etimesgut—close to the city center. It was a one hour flight to Diyarbakir and the first flight I’d ever been on where absolutely no English was spoken, the safety warnings delivered by a young stewardess with smoky brown eyes. I dozed until we were on final approach into Diyarbakir.
Ibrahim and Mustafa were detailed to this remote city for a year while the project was developed and they were eager to settle back into Ankara with their families. The work was to install new facilities for the Pirinclik Air Station (AS) (now closed) which kept a radar eye on the Soviets to the North and East. This was in the time when Saddam’s relationship with the US was less tenuous and the biggest bogeys in the region were the remains of the withering Red Menace and Iran. Tensions inside Turkey, however, were high as the Kurd region was (is) straining to decouple from Western Turkey (and Iraq and Iran). History is still being written in that region. Suffice it to say that, aside from the westerners working at Pirinclik, we were the only Yankees strolling around Diyarbakir that week.
Goats and chickens roam around mud-brick shacks and tin roofs line the road from Diyarbakir airport. Coming into the town, the dry dusty hills rise about the Tigris river—an important source of irrigation for the yearly for the famous Diyarbakir Watermelon Festival, among other food crops. At nightfall, young men bring their lean cows into town, coaxing them along with branches of green vegetation.
The pace is slow during the day; it’s darn hot and there are few women on the streets and none in the restaurants, even at night, although the daily tabloids are interesting for their, ahem, revealing photos. Men sit on short stools, drinking thick sludgy deliciously-sweetened Turkish coffee, playing backgammon under colored tarps in the many open air cafes around the city. Kids laugh and follow us, yelling “hello-hello!” There’s a sign for Kodak film hanging over a small kiosk—the only American brand around (a while before the Starbucks® phenomenon went global).
After settling at the hotel, we headed out in a few mini-vans to the site at Pirinclik for a quick look at the project. A Turkish guard looked at our IDs and we went into the ultra-compact base. It was possible to see the perimeter fence from anywhere on the grounds. I noted that the base hosted a convenience store (thankfully)—a stunted 7-11 of sorts—and a dank lounge. Nights in Pirinclik AS held little enchantment to bored backwater signalmen and contractors, who were boarded in dorms inside the fence.
That night, Ibrahim and Mustafa, now joined by four more of their colleagues, took us to the local Caravansarai (caravan-stop), a waypoint on the Silk Trade that connected the Orient to the Mediterranean. The cut-rock structure, four stories high, lay above the river and in the lee of the hill, best to catch the rays of the westering sun and lean a broad shoulder to the northerly winds and occasional snows that blew in from the Black Sea.
The roughly coliseum-shaped edifice featured an interior courtyard that was originally meant for the pack animals: camels and horses primarily. A trader would bed his beasts at night and take one of the “rooms” above, its door open to the courtyard. The Caravanerai offered shelter, protection—and vice.
In recent years, the way-station was rebooted as a restaurant. A corner of the vast courtyard—easily the size of a football field—featured linen-covered tables, a local band playing discordant Turkish music and, of course, a few belly-dancers.
We ate, danced, sang and toasted long-friendships with raki—anisette, or ouzo, best described. The liquor turns a milky white with a few drops of cold water are dribbled into the short glasses. We ate. We danced. We sang.
And the alarm jangled a wee bit early the next day.
Heads pounding, we hoped to finish early that first day on the job. The temperatures were in the high 90s and the air as dry as chalk. Passing by the base convenience store, I begged Ibrahim to stop and I bought the only Coke in the cooler; it was warm, but it was golden.
At the front desk was young MP; she was about twenty-two and bored as an old cat. She had not been there when we dropped in briefly the previous day and roused a little when Frosty came around the corner.
“Can I hehhlp yoooou?” She purred.
Frosty poured on the charm, leaning down with his elbows on the desk. “What do you do for fun around here?”
“Oh, you know, it’s soooo boring! Can’t go out anywhere in Diyarbakir and the lounge is dead.”
Mustafa cut in. “We here to test. Let Colonel Brink know.” The lady rolled her eyes, picked up the phone and cradled the handset between her head and shoulder.
She looked at her calendar. We all looked at her medals. “They’re here.” She paused. “OK, I’ll let her in.” She let the phone drop noisily in its cradle.
“Come in. Watch the gate.” The extent of security was a waist-high turnstile that clunked when we passed through. “And maybe I’ll see you later.” She looked back at Frosty, who returned a slow, interested half-nod.
We hauled our signal generators and receivers inside. A couple of local day laborers, young skinny guys wearing untidy clothes and sandals, helped us out. The heat beat at the black equipment cases and our flush faces. My mouth felt as dry as the surrounding hills.
Inside the was a typical USGOV facility with blank cubicles and a few gypsum-walled offices that lead into the shielded area, where we were to spend a few long and achy daze, er, days. We set up the test: signal generator, transmit and receive antennas, cables, amplifiers and a telephone set-up so we could communicate inside and outside of the shelter, clipping the leads to a pair of low-pass filters installed on the feed-through panel.
We did a quick visual inspection, yanked some wires that were connected through the shield, unfiltered and looked at the doors. The knife-edges were filthy; bits of fingerstock were broken off.
Frosty brought Ibrahim over and showed him the grime on the door and said, “This is no good. The metal has to be clean and shiny.”
Ibrahim walked over and kicked the dusty floor, barking something unintelligible, but completely understandable. Two young Turks scrambled like only the young can and in a few moments, they reappeared, with blue rags and square cans of some clear spirit, probably toluene. Nasty, but effective.
Mustafa motioned with his eyes to the doors. “Clean!” he glowered. The boys soaked their rags and languidly cleaned the bronze fingers on the chamber.
We set up the first measurement. We’d start at 400 MHz to assess the overall shield. It’s a quick look; if it passes at 400 MHz, most likely the rest of the frequency range would be OK. Since the enclosure was welded-steel, the magnetic field attenuation should be fine. We were mainly interested in cracks in the shield or cable leakage at the interface and power panels.
To make the measurement, a la MIL-STD-485, the signal generator is set to pump about 0 dBm into the power amplifier that feeds the transmit antenna. Pads (about 80 dB) are on the output of the antennas. Place the transmit and receive antennas one meter apart for a reference measurement. Crank up the power until the spectrum analyzer is maxed out with a healthy amount of attenuation on the front end. The level into the analyzer should be less than 20 dBm or compression could be a problem.
“Signal Generator?” “Check!
“Cables?” Check!
“Attenuators?” Check!
“Bicon, Log, Rod, Loop?” Check!
“Skoal?” Check!
“Water?” Please!
Turn the signal generator on, raise the signal until a decent level is measured on the spectrum analyzer (<20 dBm). The more power one has to transmit and the more sensitivity on the receive side, the better the dynamic range of the measurement setup. The dynamic range needs to be higher than the shielding specification to get a valid measurement.
For the baseline, record the drive signal and the input received and move onto the next frequencies and record; then, strip out most of the attenuation and locate the antennas on either side of the enclosure wall. The pad on the receive side can be a combination of fixed and variable attenuators.
It (essentially) represents the attenuation that will be measured once the antennas are located on either side of the chamber. It is not really necessary to calibrate all the cables (nor to have calibrated antennas) because this is a measurement of the difference, as long as everything is linear. That means that the input to the power amp, pre-amp and spectrum analyzer have to be below their compression points.
Record. Reduce. Solve for shielding effectiveness.
We did all that and found that the shield leaked at 400 MHz—about 23 dB, about 60 dB above target and certainly not good enough.
I went to find Mustafa, who was wandering around, picking up the coffee cups and joking with some of the laborers, who were rolling dice for a few lira. I brought him back to the room.
“Mustafa! Ibrahim. We have leak!” Frosty said in a mock accent. It was not well-taken.
“Where?” Ibrahim was annoyed.
We pointed along the corner of the wall and corner.
“Sheet! Maybe those guys didn’t clean doors good.” Mustafa snorted.
Frosty looked over at me and wagged his head; I wonder if it was as soupy as mine? He came over. “It’s not the doors. It’s a bad seam, under the floor.” Ibrahim craned to hear. “We gotta break up this floor, fix the weld and re-shoot.”
“No problem!” Ibrahim said. He was as anxious as most of us to go home. He tapped Mustafa on the shoulder and motioned to the boys, who were shining up the metal feedthrough panel and getting high on the toluene.
“Yeri Kir!” Mustafa yelled to the two Turks. “Cimento yeri parcala!” They dropped their rags and ran to get picks and shovels.
Before long, the floor, a four-inch slab was reduced to a pocket of gravely debris that was scooped into wooden wheelbarrows. The suspect seam was laid bare; by eye, it was not apparent where the leak was, but at frequency, she sang.
A few moments, more noise outside, some shouting and curious cheering and the welder came inside, pulling a cart with a huge transformer. He bent over, cleanshaven—unusual—and had big hands that were like gloves. I could not be certain, but his left eye looked sightless.
On his welding rig, which he rolled in behind him on an improvised cart, big fat burned leads were connected under a loose cardboard cover. Some writing or warning, long ignored, was on the cardboard. The red lead connected to a well-used clamp, the black lead to the case of the thing, long encrusted; a postcard of smoked glass. The welder clamped the negative lead to a bolt on the shield, picked up the stick, held the glass to his eyes and the air cracked. A lovely bead of molten metal, right under his practiced hand, flowed in the corner of the shield.
Mustafa hollered as the welder rolled up his cables: “Test again! Is it OK?”
We set up again. It passed.
“Teşekkür ederim! We can go home!”
The engineering part of this trip over, it was on to Istanbul where we meet some of the youth of that huge city and I discover why Frosty had another nickname: Spiderman. 
