EMC090 - Uses for Amateur Radio - 3/7

MORE CELL Opportunities

3. There have been cases where minor incidents have rendered the system unusable. In a major metropolitan area two minor quakes (no damage or injuries) caused about one hour of unusable cell sites due to overloading. A minor railroad incident (blocked secondary road at a crossing with a possible hazmat during the evening commute in a semi-rural area left the cell system unusable to public safety agencies. Public and media overloading was the cause. A scheduled execution at a prison provided for a media frenzy. The cell phones in that area were totally unusable for two days.

4. Then there was the Fire Chief who, while fighting an overwhelming major interface firestorm near a major metropolitan area, needed more communications. The conventional radio systems were maxed out so he went to his cell phone upon which he may have been relying too much for too long. After hours of dialing he finally got through and then did not dare break that connection and therefore isolate himself, communications wise, again.

5. Public safety official say that they have observed the media with a cell phone for each of the services available in an area. The media persons call their papers or stations on each and left the lines open to their editors or producers for the duration of their interest in that incident.

6. Rural mountainous locations away from the major highway corridors offer more unmet challenges to the cell phone systems. First, there are few if any accessible cell sites.

   Second, the propagation problems of vhf and uhf conventional radio systems are multiplied by the very low power (3 watts maximum mobile and .6 watts maximum portable) and the 900 Mhz frequency which has far less (almost none) bending or refracting capabilities around or over mountains or ridges. That same signal is also more easily absorbed by leaves and pine needles. Very heavy rain and very dense smoke will corrupt the digital "handshake" data that both the phone and cell site require in order to communicate with each other. There is the possibility of sitting on an accessible ridge or other high ground, if it is available, and hitting that cell way down in the valley. But then again, you may hit two cells on the same service at the same signal strength and neither will be able to decide (they do talk to each other through the mobile switching center) which one will handle your call. So neither one will serve you. I have experienced this myself while camping in the mountains.

7. Some of the cell carriers will provide a portable cell site that can be installed to serve the area of an incident, if the location and terrain allow it. They will even provide phones to public safety and public service organizations at no cost. All this, however, takes time - up to two days or so.

Continues next week.