On this page you will find some homebrewing projects proposals.
A little device which joins in a single microprocessor a digital
programmable frequency meter and a control logic capable to lock a
manually tuned VFO to its actual frequency.
The locking function is software inhibited when a manual tuning is detected, so as to provide a completely automatic working
FLL VFO (PDF file - 130 Kbytes)
"palm size" 1,5 W QRP rig operating on the HF in DSB and CW.
A lot of fun with this ultra-simple project wich employs a few components and is very easy to build and to align.
You may build it in the crystal or VFO (varicap) controlled version. The receiver is a direct conversion design.
DSB_RIG (PDF file - 100 Kbytes)
|Although designed primarily for learning CW, new and experienced CW ops are
sure to like this simple and inexpensive CW decoder.
The decoder uses a PIC16F84 microprocessor and a NE567 PLL as analog interface. The software automatically adapts to incoming CW at speeds between 5 and 30 WPM.
The circuit has been published in QST and appeared on the cover as reproduced here.
CW-DECODER (PDF FILE - 47 Kbytes)
A PIC16F84 based programmable micro-counter, the ideal complement for your next QRP transceiver. The counter will read frequencies over 40 MHz and needs only 15 mA of current. It is also possible to connect a prescaler with several prescale ratios, in a word.... it should be a pity not to build it
PIC_FREQ (PDF FILE - 60 Kbytes)
CW QRP Transceiver for 40 meters band. The TX and RX sections are independent modules
and may be built separately. Among the main features are :
5 W output power, Full break-in, superhetherodyne receiver, four crystal ladder filter, full coverage of the band with a varicap controlled VFO and SSB reception capability.
QRP 40 m (PDF FILE - 100 Kbytes)
meters CW QRP Transceiver.
Only a little more complex RIG, but you'll find again RX and TX independent modules.
Main features : 5 W output power, Full break-in, superhetherodyne receiver with MOSFET RF and mixer stages, four crystal ladder filter, AGC and CW band coverage with a conversion varicap controlled VFO.
QRP 20 m (PDF FILE - 100 Kbytes)
generation' VFO wich makes use of the DDS technology. It is equipped with an AD7008 DDS
from Analog Device and an ST62 microprocessor from Thomson, the frequency and the
tuning step are shown on an LCD display. An ideal addition to your next professional
VFO DDS (PDF FILE - 300 Kbytes)
A "partial synthesis" VFO using the PLL technique, if you want to abandon the classic "free" VFO, but without excessive trouble, this project is for you.
PLL VFO (PDF FILE - 100 Kbytes)
frequency reader you may employ with a classic conversion VFO or to replace the mechanical
tuning in some older RIG
CMOS Reader (PDF FILE - 120 Kbytes)
|Some projects from “Il Club Autocostruttori” of the Padova ARI club (www.aripadova.it)|