If anyone can offer more information on the former TD/TH network, please email me. Thanks!
Decades ago, before AT&T's nation-wide network was using fiber and AT&T was referred to as the Bell System, all long distance traffic was sent over coaxial cable or microwave point-to-point links. This network carried AT&T's long distance telephone service, the Military's AUTOVON phone network, and TV Station video feeds. Some sites had the capability to detect nuclear blasts and act as relay points for ground based low frequency communications. Though other telecommunications companies used long haul microwave (MCI, PacBell, Western Union), AT&T operated the largest network.
Long haul connections were via very thick coaxial cable referred to as "L" carrier. There were many different types which related to the capacity of the line (L-1, L-2, etc). The coaxial cable route was referred to as the "Transcontinental Cable Route." Often you can find lone wooden poles with simply a sign attached to them signifying the route and to call AT&T before digging.
When coaxial cable was not used, microwave point-to-point links were used. According to what I am told, cost was the deciding factor. These microwave sites more commonly used the 4 and 6 gigahertz common carrier bands. These bands are referred to as TD and TH with the number, such as TD-2, referring to capacity. This is not always the case though. Sometimes some sites are referred as DR-6 or AR-6. The 6 being the band and the DR or AR being the transmission type (Digital or Analog).
Today, most of the AT&T Long Lines facilities have been decommissioned and sold to American Tower. American Tower has sold or is selling many of the bunkers and leasing the tower space out. Many of these sites will have the remarkable microwave horns removed. Though the AT&T Offices seem to keep their towers intact with antennas.
These sites represent telecommunications history and the former Bell System, the only monopoly worth it. It's important to capture these sites before they are dismantled and removed.
©2003 Wayne Hayes
To contact me: 2microwave6 -> thebriarpatch.org
05/29/2003
