Receiver Direct-Conversion Receiver For 80 Metres

i1 RECEIVER DIRECT-CONVERSION RECEIVER FOR 80 METRES What better occasion to present an ultra- simple 80 m receiver than this month"s issue devoted to amateur radio and TV? An ideal project for the holidays, this CW/RTTY/SSB receiver is inexpensive, yet has good sensitivity and selectivity. You will have it ready in no time, and it only requires headphones, a set of bat- teries and a long-wire aerial to bring in the 80 metres band, popular among hams around the world for its reliable propagation characteristics. The tuning range of the receiver dis- cussed here is about 3.5 to 4.0 MHz, a section of which is assigned to licenced radio amateurs. In most areas in the world, the 80 m amateur band extends from 3.5 MHz to 3.8 MHz. Predominant modulation methods are single-sideband (SSB), continuous wave (CW) and FSK RTTY (radioteletype based on frequency shift keying, using an SSB transmitter). The 80 m band has some interesting properties as regards propagation. Daytime range is usuall...