But you really need to be able to count on a solid connection since dropped calls are expensive and bad business for everyone. Conventional analog service may offer the best reception. An analog communication link can keep going despite heavy static or interference. A digital signal gives up when it encounters too many errors in the bit stream, a point which, if one had analog, one could keep talking despite the noise on the line. Unfortunately, most carriers have switched their old analog channels to digital ones to increase capacity.
Some people use car mounted mobiles instead of hand held units.
Car mounted ones are allowed the most power, hand helds the least. An old brick phone is in the middle of the power band. A really good antenna helps even more. Sometimes two, depending on how your installer sets things up. Even with the best equipment you are still limited by your carrier's infrastructure.