Strange Mysterious brick buildings with Tin roofs in middle of farmers Fields . What did they do or serve in Tristate

 A friend of mine recently purchased a large  property out by Pittsburgh International Airport and had this building on it  Very similar to the building in picture  below located in a farmers field in Washington County Pa.  

 At first we thought it had something to do with the Airport ,but after exhaustive research we could find nothing . No utility said it was theirs either but what could it be.  The family members knew nothing about it and the ancestor who owned the property had long ago passed .

Well after belonging to a FB Group about AT&T Long lines Service  which I was part of in alarm industry back in the McCullough Loop days I finally figured it out after seeing similar pictures posted in that group . Unofficially these buildings are known as K-Carrier Huts or simply K- Huts   and they where part of the Cold War Era AT&T Long lines  communications system which consisted of Hardened  Microwave Tower Sites which served as back up to a multi pair Buried Coaxial Cable which ran all across the country to provide critical phone and video communication and path for certain government Data.

While most of the AT&T Long lines History is available on line including You Tube not much can be found on these huts as some of Landlines is still classified . 

https://telephoneworld.org/long-distance-companies/att-long-distance-network/history-of-att-long-lines/

Thou most of the landlines system was decommissioned in late 90s early 2000s and replaced with fiber-optics and Satellites some of it in more rural areas is still in use.  

What is available to the public is that these K huts as they where known served as Amplification boosters  to the Coaxial system .

When the buildings where decommissioned and sensitive equipment removed they where given to the farmers to use. Most now have started to deteriorate and nothing to see inside.