A 1961 Drake 2B Receiver using an RTL-SDR as a Panadapter
The Drake 2B is an old analogue tube based radio from 1961. Although it is so old it is still considered a decent shortwave receiver. Over on YouTube user M0HBR decided to bring his Drake into the modern age by coupling it with a panadapter made from an RTL-SDR dongle. A panadapter is a device that allows you to view the RF spectrum and waterfall of a normal radio.
To do this he tapped into the 455 kHz IF output of the Drake and amplified it with a homebrew FET source-follower, before connecting it to the RTL-SDR. He then uses the HDSDR software to listen to and display the received signals on the waterfall.