Actual widespread use of rudimentary analog microwave PTP links is a post-WW2 thing. The earliest widespread sites used square delay lens antennas in the 2 GHz

Actual widespread use of rudimentary analog microwave PTP links is a post-WW2 thing. The earliest widespread sites used square delay lens antennas in the 2 GHz band, later 4 GHz. See black and white photo here: https://long-lines.net/places-routes/Yellow_Springs/index.html https://long-lines.net/places-routes/Yellow_Springs/index.ht... Some of the oldest AT&T Long Lines sites with this type of equipment were built in the general corridor from Boston-NYC-WA DC