https://stream.echo6.co/videos/watch/b9f5396d-2e1e-420d-ae13-69f9ba501ec7 Range tests on a 28.571 MHz crystal oscillator module putting out a few milliwatts of power. The module was keyed with its output fed to a 1/4 wavelength antenna plus radial. The module is fed with 5v via a 7805 voltage regulator. A microcontroller keys it. For anything other than a quick test the use of a low pass filter (100pF x 2 & 0.2uH) is recommended to attenuate harmonics. This test was with Morse. Modules can be made to transmit AM if their supply voltage is modulated but their transmitting range will be less. DSB should also be possible if their output is fed to a balanced modulator. Similar unit built by others http://www.ae5x.com/docs/Fire-Ball_QRP_Rig.pdf 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 05:56:52 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/b9f5396d-2e1e-420d-ae13-69f9ba501ec7 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.