https://stream.echo6.co/videos/watch/d5758f80-57ad-4bcb-82c7-57ee4443894e A refined VHF solar powered pulsing radio beacon. Uses a 2 transistor multivibrator 400 Hz audio oscillator pulsed by a flashing LED. This modulates a one transistor milliwatt VHF transmitter. The coil in the RF transistor's collector is 9 turns of tinned copper wire 6mm diameter and spread out to about 10mm. When light is low the pulsing is just CW but becomes modulated CW when it's brighter. VK6FH circuit http://www.vk6fh.com/vk6fh/simple%20radio%20beacon%20mod.htm 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 01:26:57 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/d5758f80-57ad-4bcb-82c7-57ee4443894e 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.