The study continues (even though some have given up), but every once in awhile we experience a real life comparison that answer a lot of questions as to which is the best communications technology - analog or digital? We were recently asked to provide pricing for twenty portable radios to cover a multi-building industrial complex. We were a little dubious as to whether this system would perform to the customers expectations without the use of a repeater.
They wanted three work groups working separately from each other although on occasion, they wanted the ability for the work groups to be able to talk to each other. They also wanted all work groups to be able to talk at the same time without waiting for the channel to clear. Not, a problem UNLESS a repeater was required. If a repeater was required, it meant that we needed at least two repeaters trunked, and possibly, three repeaters for conventional operation! Our technical friends out there already know that two repeaters with dynamic (automatic) channel selection can do the work of three repeaters with user selectable channel switching. Is has something to do with what engineers call Erlanger curves (a topic for another time). Now, back to our story.......
We delivered some demo portables to these throughout the plant - good top quality brand name models. They didn't cover the entire plant area. Clearly a two channel trunked or three channel conventional repeater system was required. We figured around fifteen thousand dollars for either system. Now it was time to test the digital radios.
Guess what, the digital radios covered the entire plant area WITHOUT the need for a repeater - a fifteen thousand dollar savings! The analog radios cost the user around two-hundred fifty dollars each - the digital radios around four hundred dollars each. That meant the analog system would cost twenty thousand dollars compared to the digital system at eight thousand dollars. The digital system worked out to be twelve thousand dollars LESS than the analog system!
We concede this is not a fair comparison. So the question is, what happens if we DO require a repeater for the digital system? The answer is that a five thousand dollar investment buys a two channel trunking repeater (you can do that with digital). So we add five thousand dollars to eight thousand dollars (the cost of twenty digital portables) and we come up with a total cost of thirteen thousand dollars. The digital system is still seven thousand dollars less than the analog system.
