As a rather old fashioned radio ham in many ways, I’ve always had a hankering to build a linear amplifier for the HF bands. I’ve got lots of ‘junk boxes’ with stuff in them for different ideas such as: 813’s, QY3-125’s, 811A’s, 4CX250B’s etc… plus various transformers and other essential ‘stuff’.
There are lots of designs out there but I could never make up my mind which one to go for…and of course everyone else has different opinions on which is best. When the ARRL released their ‘RF Amplifier Classics’ book, I thought the choice would reveal itself. How wrong I was, what a disappointing book…and on this many others agree.
However, the man who started Linear Amp UK, a certain Peter Rodmell G3ZRS, has now written a book. Wow, it’s everything I’d hoped the ARRL book would be. His website is here if you’d like to take a look. Simply brilliant.
Profusely illustrated, the book takes you briefly through the history of valves, valve RF amplifiers and how Linear Amp got started and grew. It then essentially goes through all the classic Linear Amp designs…in enough detail so you can either duplicate or use ideas in your own amplifier.
Peter then describes in detail, how to build rugged, high performance amplifiers for HF, VHF and UHF. There are sections on safety, troubleshooting and repairing amplifiers…even an ATU design suitable for QRO use. If you have an interest in amplifiers or intend to build your own at some point, you need to buy this book!
Peter can supply it himself from his website, or if you are an RSGB member, you can save a little by buying it from them.
So…it looks like I’ll be using four 811A’s for my amplifier. But the QY3-125’s might just end up in a G2DAF amplifier, to resolve all the controversy over the linearity of said design 😉