AT&T Long Lines: The Waveguides and Antennas

This video describes waveguide technology and how it was used in the AT&T Long Lines microwave radio relay network.

My original Long Lines video:    • AT&T Long Lines: The Wireless Network Befo...  
Long Lines Power Plants, Batteries, and Generators:    • AT&T Long Lines: The Power Plants, Batteri...  

Video chapters:
0:00 Introduction & History of Waveguides
2:10 Waveguide Filters
2:43 AT&T Long Lines Channelization & Improvements
4:13 Other Waveguide Applications
5:03 Today

Correction:
2:44 From the Bell Labs Record, It appears that the TD-2 system started with 6 channels in each direction (for 12 channels total). The ferrite cores seem to have allowed them to use additional channels at smaller antenna separation angles in cases where a tower was part of multiple paths (e.g., paths joining, crossing, or splitting). I plan on making several more videos in this series based on what I've read.

All content used in this video is in the public domain or qualifies as fair use for educational purposes.

Sources and further reading:
https://en.m.wikipedia.org/wiki/TD-2
https://long-lines.net/
https://long-lines.com/
https://en.wikipedia.org/wiki/Wavegui...)
https://en.wikipedia.org/wiki/Coaxial...
https://en.wikipedia.org/wiki/Wavegui...
https://en.wikipedia.org/wiki/Polariz...)
https://en.wikipedia.org/wiki/Radar
https://en.wikipedia.org/wiki/NEXRAD
https://en.wikipedia.org/wiki/Slot_an...
   • Waveguide Resources  
https://en.wikipedia.org/wiki/Beam_wa...
https://en.wikipedia.org/wiki/Optical...
https://en.wikipedia.org/wiki/5G
https://www.megaind.com/rigid-vs-flex...
https://en.wikipedia.org/wiki/Phased_...
https://en.wikipedia.org/wiki/Starlink

Additional imagery obtained from:
https://pixabay.com/collections/long-...
https://www.facebook.com/photo.php?fb...
https://www.google.com/maps/