Few ever venture into the southern Negev and virtually no one does in the inferno of August.
Barren rubble extends for ridge after ridge of scorched emptiness. T.E. Lawrence-“Lawrence of Arabia”-had described it as “the most inhospitable desert” in the Middle-East. The Bedouin had abandoned it 15 years before. Except for resupply, we would see no other human beings for six days.
Geologically, the Negev forms the eastern most edge of the Sinai Plateau. It abruptly ends at the Arava-lying 2,000 feet or more below at the base of a torn and almost impenetrable escarpment.
Myself, an English Arabist, and our two guides had ventured south through three days of stifling heat on what was to be an eight day journey. Our two camels could carry sufficient supplies for only seven days. For this reason, we had planned to rendezvous with a land rover on the following afternoon to replenish our water and food.
Toward evening we struggled to the crest of a ridge. To my shock, our guide pulled out a Nokia cellular phone and dialed our base camp to report our position and confirm our rendezvous. The phone was registered on Cellcom, Israel’s second cellular carrier. Its TDMA/IS-54 network is not as mature as that of Pelephone, the competing N-AMPS carrier. This notwithstanding, the call went through.
I looked around, trying to find possible line of sight to a cell. All I could discern were more ridges. In response to my questions, our guide told me that it was possible to make cellular calls from virtually every ridge and sometimes other places, as well.
From 1989 through 1993, Herschel Shosteck Associates, Ltd. had undertaken seven separate studies to evaluate the economic feasibility of “Personal Communications Satellite Service”-the market for handheld satellite telephones-such as promoted by Iridium, Inmarsat (ICO) and Globalstar. In each case, we had concluded that terrestrial cellular would become so pervasive by the time PCSS was launched, that demand for PCSS would be insufficient to cover the infrastructure and operating costs. Little did I realize that I would personally experience such cellular reach.
Three days later, we had descended into the Arava. We had paused in the shadow of a wadi wall opposite a ridge. Our guide again took out the phone to coordinate with our base camp. At his first dial attempt, the phone registered “no service.” He moved two to three feet. The phone registered five bars. I looked around. We were in a depression between a wadi wall and a ridge. There was no way that we could receive a direct cellular transmission.
Even more perplexing, we could not have been within 12 kilometers (7 miles) of a cell site-the approximate limit at which TDMA/IS-54 (but not IS-136) can tolerate multipath effects without timing degradation.
How then was cellular reaching such remote areas beyond its nominal coverage area?
Upon my return to the United States, I reviewed early cellular history. In 1986, Cantel in Toronto and Cellular One in Buffalo angered numerous customers by charging them for international calls. Their cellular signals were “skipping” up to 130 kilometers (80 miles) across Lake Ontario and “roaming” on the literally foreign system. Other stories had cellular signals from Ameritech in Chicago skipping across Lake Michigan or signals from the Denver system bouncing off snow covered mountains to provide service 110 kilometers (70 miles) away.
In the Negev, at least, three phenomenon appear to be operating. First is “reflections.” TDMA/IS-54 signals degrade rapidly in multipath environments. However, a short reflection off the face of a ridge may not affect them. Second is “defraction.” RF signals passing over the top of a ridge might be bent to parallel the surface of the early, thus providing service to the next several ridges in line. Third is “ducting.” This can be caused by temperature inversions that in effect cause RF wave guides in the sky.
Regardless of the reason, our guides know where to find RF in the desert. Much of our journey was to places where no one had traveled since the last rain of 20 months before. Thus, calls from the trails of the Negev add but minuscule traffic to Israel’s cellular systems. However, if cellular costs but a few cents a minute (Israel boasts among the lowest cellular tariffs in the world), few people may shift to PCSS which would cost 30 to 100 times as much. This raises further doubts about its market viability.
Dr. Herschel Shosteck is President and CEO of Herschel Shosteck Associates Ltd., international economists who specialize in measuring, analyzing and forecasting cellular and related markets.
