https://stream.echo6.co/videos/watch/bca47c6e-e421-492c-82df-5d38b54b8077 An amplified crystal set receiving amateur activity on 80 metres. There's nothing special about the circuit - it's just a normal crystal set with an airwound coil covering 3.5 MHz. Audio is fed to a 1 transistor amplifier - again a common circuit - to drive a crystal earphone. The main point of this demonstration is the effect of the 3.5 MHz beat frequency oscillator (previously featured on this channel). It provides some RF bias to the diode. This improves its weak signal performance and allows reception of CW/SSB signals. Hence it's effectively a direct conversion receiver. However the gain seems to be a touch higher - almost all very simple DC receivers have at least a two transistor audio amplifier, whereas this uses just one. Note that you do need a good antenna to get good results on this or any crystal set-type circuit. If it's not resonant an antenna coupling unit is essential - without one you'll hear nothing. Part 2 follows. PS: If you liked this video please consider supporting Amateur Radio VK3YE by: Subscribing on YouTube,, Checking my books page at https://books.vk3ye.com, Shopping on Amazon via: https://amzn.to/3iiDQXv, or, Shopping on eBay via: https://ebay.us/i9DuWP (then if you buy something I'll get a small commission at no cost to you) Sat, 09 May 2026 06:13:21 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://stream.echo6.co https://stream.echo6.co/client/assets/images/icons/icon-512x512.png https://stream.echo6.co/videos/watch/bca47c6e-e421-492c-82df-5d38b54b8077 All rights reserved, unless otherwise specified in the terms specified at https://stream.echo6.co/about and potential licenses granted by each content's rightholder.