The Long Lines are a remarkable engineering achievement in two senses:
1. They are a milestone of microwave RF transmission coming to maturity, and being widely and economically used. This includes such aspects as analog transceiver front-end design, antenna design, reliability know-how etc.
2. Long Lines managed to relay analog voice calls over dozens of hops with enough quality to allow low-distortion human and early fax/modem communication over thousand of miles overall. This is an amazing achievement for the American society and economy at large.
Just to highlight how far we've come in terms of data capacity, a single TH-2 Long Line link could carry 900 calls. STM-1, the slowest standardized carrier grade payload framing currently in use (predominantly over fiber), carries 63 VC-12 containers, each with an E1, for a total capacity of 1890 calls.
Of course, the above is not an apples to oranges comparison as they use different transmission media. I was not able to locate information about the bandwidth of specific Long Line link types to calculate RF spectral efficiency, but the ballpark figure is an improvement of ~100x when compared to modern digital microwave links of similar bandwidth (accounting for both modulation and digital voice compression).
1. They are a milestone of microwave RF transmission coming to maturity, and being widely and economically used. This includes such aspects as analog transceiver front-end design, antenna design, reliability know-how etc.
2. Long Lines managed to relay analog voice calls over dozens of hops with enough quality to allow low-distortion human and early fax/modem communication over thousand of miles overall. This is an amazing achievement for the American society and economy at large.
Just to highlight how far we've come in terms of data capacity, a single TH-2 Long Line link could carry 900 calls. STM-1, the slowest standardized carrier grade payload framing currently in use (predominantly over fiber), carries 63 VC-12 containers, each with an E1, for a total capacity of 1890 calls.
Of course, the above is not an apples to oranges comparison as they use different transmission media. I was not able to locate information about the bandwidth of specific Long Line link types to calculate RF spectral efficiency, but the ballpark figure is an improvement of ~100x when compared to modern digital microwave links of similar bandwidth (accounting for both modulation and digital voice compression).