Which Freqs work best in built up areas

[CharlesHarris]

Your mileage may vary, but if I recall correctly, PMR446, like FRS in the US, is limited to 500 milliwatts transmitter output with a fixed antenna on the radio, typically a short helical coil, with less than unity gain.

Public safety band UHF portables, have detachable antennas, transmit at about ten times the RF output of an FRS or PMR radio, and have more efficient, base-loaded, flexible quarter-wave whip antennas, which are more efficient radiators and have better range. A 5-watt UHF portable, such as a 70cm ham rig, with efficient antenna, transmitting direct unit-to-unit simplex, not through a repeater, provides reliable communications vertically ten floors, and horizontally ten city blocks or more, depending upon ground clutter and elevation.