Mobile Network Coverage

How many BTSs are needed to completely cover a city on average? 50 ? 100 ? more/less ? If each operator has its own tower, then it would be 250 to 500 towers in a city (assuming there are 5 operators, 1 BTS each tower).

Around two years ago, when I came back from Germany after several years leaving, almost every 1 minute or maybe less of my trip from Jakarta to Bandung (also inside the cities) I saw a BTS tower!! Several times later people told me that indeed due to "cellular wars", our cities have turned into "Hutan BTS" (BTS forrests). Well this is the fact. This might:

• positively influence economic sectors (local cellular-supporting industries, maintenance outsourcing industries, PEMDA's income ? etc.)
• also negatively impact several other things e.g. introducing "optical" polution, destroying city layout (regulation is far slower than business!), injecting more electromagnetic radiations to the home (well, EMR-TTH :-)) etc.
  

I almost forget that the title is about mobile coverage. Below are two pics showing coverage areas of Indosat and Excelcomindo. I don't have that of Telkomsel right now, but intuitively, for TSEL you might see more "reds". Statistical numbers and values will be addressed in special threads, maybe in the next days.

Network Coverage (Indosat Q1/2006)

Network Coverage (Excelcomindo Q4/2006)

Looking at these, it seems that they might use a similar software ? Nokia-based ?