https://stream.echo6.co/videos/watch/7d02d880-c692-4aeb-8acf-2eb4ed1d2e4e A demonstration of a very simple headphone radio that uses only a dozen parts and just three active devices. Unlike most other 1980s radios, this one is AM-only and uses a TRF circuit. Other radios used more complicated superhet circuits and probably had FM as well. Compared to superhets, TRF is simple and cheap. However there are no intermediate frequency circuits so it is less powerful and selective than superhets. However, provided the received station is fairly strong a TRF set can be very pleasant to listen to because its broad selectivity does not 'strangle' the signal like many cheap superhets. The set shown here cost $5 in an op-shop. It was bought for 1.8 MHz use, but sensitivity is too poor so it will remain as a novelty broadcast set. 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) Sun, 10 May 2026 10:58:32 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/7d02d880-c692-4aeb-8acf-2eb4ed1d2e4e 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.