https://stream.echo6.co/videos/watch/baae3bf9-bc90-4d9d-a38f-80656b786e39 Sometimes it can be hard getting a stable RF power amplifier chain working. Here's my take on a good design from the Norcal Sierra QRP transceiver of the 1990s. I've made some substitutions to suit available parts, most notably replacing the 2N3553 with three BD139s in the PA. Sierra article: http://www.arrl.org/files/file/Technology/tis/info/pdf/96hb1789.pdf JBOT amplifier: http://www.dl2keb.de/drupal/de/node/320 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) Mon, 04 May 2026 01:22:51 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/baae3bf9-bc90-4d9d-a38f-80656b786e39 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.