The first Collins was installed in 1974 while I was at Himatangi. The aerial output was coaxial (the black tube in the top right corner of the TX picture) and it fed a coaxial aerial switch matrix mounted on the wall behind it. The output of the matrix went to a high-powered balun transformer for converting the 75 ohm coax output to the standard 600 ohm open-wire feeders used on the outside plant. The transmitter was self-tuning (from data selected at the drive unit) and fed a purpose-installed vertical wideband double-discone for use on the HF shipping radiotelephone service.
– Rex Johnson