When we started wireless ISP in in early 200x, it was common to run 2.4 GHz links with 5+ km distance, having 24 dB antennas on each side. with the basic 17 dB

When we started wireless ISP in in early 200x, it was common to run 2.4 GHz links with 5+ km distance, having 24 dB antennas on each side. with the basic 17 dBm radio one was 20 dB over EIRP limit... Here in Czechia, there was also another unlicensed band, 10.5 GHz, that has more sensible regulation - instead of EIRP limit, there was PA limit (power before antenna). So one can do long-range links with large enough antennas and most long range links was later converted to these. Unfortunately as this is local unlicensed band, radios for that were orders of magnitude pricier than generic wifi.