I first saw the 618T when I was a radio man for Braniff Airlines
-- each B 727 had two. On the night shift, I would fire one up and talk to hams on 20 meters right from the cockpit while sitting on the hangar ramp.
Years later, I became a pilot for ATA and we used the 618T's on every Atlantic crossing to report our position at each
way point on the [L-1011] I was able to find one on eBay, a dash-3 618T the dash three only needs about 30 amps of D.C. and has a built in 400 cycle ac inverter to power the fan and frequency motors
etc. Below are a pictures with sides open a picture of the PA
module [two 4cx250's ] my homebrew control panel using the cockpit control box. I only had to add line level mic audio and I run the RX audio to computer speakers or earphones.
In order to make operation simple, I use a Hammarlund 212 to sweep the ham bands and then reset the 618 to the stations I find on the Hammarlund. and simply switch the rx audio from
Hammarlund to 618T audio. I have yet to find the auto-tuner for the 618t as used on the aircraft installations, so I use a Butternut all band vertical. I
don't have to do any tuning then. Also, there is a picture of the gray
Collins control unit that was used with the 618t's when they were in Vietnam service on