The AN/GRR-5 Receiver
Here's my "boatanchor" ex-military shortwave receiver. It tunes
1.5 to 18 Mhz, receives AM, CW and, with a bit of work, SSB. The neat thing
about this radio, last repaired in 1962, is that it runs on AC or DC. That's
what the bottom unit (the power supply, PP-308) is for. It contains two
vibrators and four transformers, along with a relay and some tubes. The
top unit (R-174) is the actual receiver, which is tuned by turning the
large dial in the center. The little white dots visible around the left
hand side of the dial are actually "presets". They are small locking studs
that work like the buttons on a car radio to physically detent the dial
at 10 locations, allowing the operator to preset his favorite stations.
The white rectangle is for recording band and station information for each
preset.