There was a time when radio hams and electronic hobbyists seemed to have more time to build things. Maplin used to publish an excellent magazine in those days…for just 85p…that featured projects you could build, along with hints and tips for experimenters.
In September 1988, Maplin introduced a really excellent Direct Conversion Receiver which many people built from their kit of parts. Yours truly waited too long and they discontinued it before I could get one. Fortunately I have kept the magazine all these years.
Ebay however, yielded a non-working but tidy example as shown in the photo. I doubt the one I bought ever worked as there were lots of dry joints, bad cable crimps and simple errors in construction; thankfully they were relatively easy to fix.
Mine covers 80m and works very well indeed…there is a frequency counter output on the back which makes tuning a little easier. For such an ‘old’ design, its performance is among the best direct conversion receivers…with the exception of stability which could be a little better. Varicap tuning using a standard carbon potentiometer is not the best solution…especially if the pot is 25 years old.
I’ve posted a scanned copy of the full article covering the Maplin Direct Conversion Receiver in my downloads area; beware though, it is almost 50MB!