In line 10 of Table 5.2 of DESCANSO IV - Voyager Telecommunications it shows a value of the uplink receiver noise spectral density of -166.7 dBm/Hz, which is 196.7 dBW/Hz which is 2.1E-20 Watts/Hz = $k_B T$. With $k_B$ = 1.381E-23 J/K that's a temperature of about 1500 K (which seems really hot!) and that agrees with the stated operating temperature of 1545K which again, seems really hot!
In Table 5.3 for the downlink receiver at DSN, the noise temperature is 21K and that's consistent with it being cooled to about 13K. But I can't understand this 1500K figure for Voyager, it seems unphysical unless the technology is so old that the source of the noise is the 1970's era front-end transistor itself.
Were they really that noisy back then?