I first laid eyes on this book when Glenn VK3PE brought it to an Amateur Radio Victoria Homebrew Meeting a few months ago. Eamon Skelton EI9GQ writes the ‘Homebrew’ column in RSGB’s RadCom. I don’t see RadCom (my loss) so it was a pleasant surprise to skim the pages and see every aspect of building a relatively high quality transceiver getting a good, readable coverage, with full construction details.
It looks like a build-it yourself manual but in fact it’s the author’s story of the complete construction project, conducted over a year. They systematically work through the transmitter, then the receiver, starting with the relevant theory for each module, and describing their thoughts on how to tackle each stage.
All design is compromise, but good design makes the compromises disappear. The various choices and consequences of these are tossed back and forth for each building block. So for the receive mixer — a critical state in any superhet for many reasons — they discuss SA612s, packaged DBMs, DIY DBMs, triple-balanced mixers, H-Mode mixers and so on. Several of these options are bread-boarded, tested and measured. One is chosen and then built out for inclusion in the transceiver (no spoiler here, you’ll have to buy the book to find out which one!). It’s a practical way of covering the relevant theory.
When their choice is made, the authors go through the building process, sometimes with a PCB but mostly ‘dead-bug’ style. They describe their sources for various parts, and construction techniques for toroids, mounting and heat sinking power transistors, DC supply decoupling, capacitor selection for filters, etc. Each time, the actual performance of the finished module is described, so it’s a primer on testing and evaluating circuits as much as on how to build them.
The transceiver that comes together piece by piece is a single conversion multi-band superhet, bandpass filters shared between receiver and transmitter, carefully placed gain stages, a HyCas-like IF strip with commercial crystal filter, and an AD9951 DDS and controller. The linear amplifier stage uses RD16HHF1s for 15 to 20 watts across all bands. The book ends with coverage of the author’s 200 watt (MRF151) and 400 watt (SD2931-10) afterburners, with enough detail for you to reproduce these beasts, if QRP becomes too hard to bear at your noisy urban QTH.
Most importantly, this compact book is easy and enjoyable to read, on your commute, or at the shack bench. It set a few things straight in my mind via its pragmatic answers to some of the less documented circuits or techniques I’ve had to discover myself from a lot of different sources. Things like buffering/driving a DBM LO port from a low-level DDS or PLL output, low pass filtering the VFO and BFOs, and high-side relay switching from a PIC or Arduino. The receive mixer discussion is particularly helpful. Although each module discussion resolves to the author’s preferred circuit, other options are covered, allowing you a choice — there are several IF stages to choose from, and both diode or relay switching are described, for example.
While the book is focused on the HF bands (160 to 10m inclusive), the transceiver is designed to work at 6m as well. Because it’s all modular, you can take whatever you need from the pages. I’ll probably try the AGC amp, and the 4-element bandpass filters look good. Most of the parts are garden variety and will not be challenging to source. In a few cases I might try an on-hand substitute with confidence.
Recommended for anyone fascinated by the workings of a reasonably high performance analogue/digital (pre-SDR) transceiver. Maybe those uBitx owners who got a taste of hacking RF hardware and would like to tackle a scratch-built receiver, transmitter or transceiver project themselves.
My copy was purchased here. I have no affiliation with the RSGB or the seller.