Among others:

• Zero Retries: https://zeroretries.substack.com/feed
• Daniel Estévez: http://destevez.net/feed/
• Computers are bad: https://computer.rip/rss.xml
• GB2RS Propagation News: https://rsgb.org/main/blog/category/news/gb2rs/propagation-news/feed
• F1IEY - ATELIER RADIO: http://f1iey.blogspot.com/feeds/posts/default
• N5HXR: http://thestone.zone/feed.xml
• Radio Adventures @ G4GUO: http://g4guo.blogspot.com/feeds/posts/default
• Radio Engineering Projects powered by DK7IH (Peter): https://radiotransmitter.wordpress.com/feed
• Rob's Blog VK4HAT: https://robs-blog.net/feed/
• Electronic Projects for Fun: https://electronicprojectsforfun.wordpress.com/feed

I'm reading those using Thunderbird, but I've heard good reviews about QuiteRSS too.