My guess is Collins Radio, just from the description of "Around the World around the Clock"
Collins Radio did make a lot of radio gear for the Military, I think they made a lot of the Boat Anchors such as the Proverbial R390.
Whilst working at the Long Beach Naval Shipyard in the late 60's and 70's there were a lot of tuners and couplers that were pressurized, the ones I worked on were filled with Nitrogen gas, I don't remember the pressure but I think it was about 20-30 PSI. This was to prevent salt air contamination. And since it was Nitrogen it had no Moisture and that prevented condensation inside the couplers and tuners even in cold weather. Boy I sure replaced a ton of Neoprene gaskets. We used Dow Corning grease to help seat and seal those gaskets.
I never saw that type of pressure gauge used, so I think it was a sales promo gift. We used calibrated
Dial pressure gages for accuracy. The one you show isn't accurate or reliable on consistent readings. They were probably given out as tire pressure gages. However the couplers did use the automobile and bicycle type of stems to fill them with.[You must be registered and logged in to see this image.]
TN-342/WRT Navy Transmitting Antenna Tuner
Complete[You must be registered and logged in to see this image.]
Top end, they used silver wire for the coil and notice the sliding shorting ring to tune.[You must be registered and logged in to see this image.]
This is the bottom with the drive motor assembly, there were two geared bars that had notches to prevent over travel and roller micro switches that detected the detents to stop travel and of course the motor was DC to allow travel up and down. [You must be registered and logged in to see this image.]
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