Two Packaging Versions You Can Build
The Rockless QRP Transceiver grew from great enjoyment of the crystal controlled Rockmite QRP transceiver designed by Dave Benson of Small Wonders Laboratories, as I explain in my article in the November 2009 issue of QST. (The Rockmite was featured in the April 2003 issue of QST)
The Rockless extends the usefulness of this small basic circuitry QRP transceiver by including a VFO so that one can tune across the band and answer CQ’s, etc. While the design is very similar to that in the Rockmite, the Rockless includes several circuitry changes to accommodate VFO control. The circuitry uses four 2N4401 Transistors, two 2N7000 Mosfet, and three eight pin dip chips that plug into sockets. My first effort was to package it an “ALTOIDS”™ size tin, using a miniature 9mm square 10K potentiometer for varactor tuning. Later it was found that a 10 turn potentiometer gave far superior band spread and tuning experience. But the use of the 10 turn tuning control required a larger housing. The mini version is for those who want the minimum size in a VFO controlled QRP rig. Tuning is touchy but manageable. Both versions use the same two circuit boards so it is just a matter of packaging. Following are descriptions of the two packages.
At the left you can see the VFO mounted vertically and wired to the main board. The two boards slide into the case as a unit. The VFO is mounted by the tuning control. The Main Board is held to the base of the case by 4-40 bolts. This package shown has no volume control, but a miniature potentiometer may be mounted on the right side of the case. Another approach is to use a toggle switch between two fixed volume settings.
MINI-ROCKLESS READY TO GO
At Right, the mini version all packaged and ready to go in the 2 3/8” by 3 ¾” housing. You have the “Whole QRP World in Your Hand”. Power output runs from over a half watt to one watt in models already built. The push button controls code speed and frequency shift.
ROCKLESS WITH TEN TURN TUNING
With the top lid open you can see the Shielded VFO with leads extended out to the10 turn tuning control. The Main Circuit Board is installed just behind the VFO. The controls are from left to right: volume, cw speed and frequency shift, and main tuning. The home page shows the finished package. The box size is
3 ½”X 5 3/8 ”X 1”.
Remember the Rockless is a basic transciever with direct conversion in the receiver. No filters, noise blankers or other devices. But if you want the thrill of contacting hams with a simple vfo controled QRP radio you built then give the Rockless a try. It will give you a new appreciation of what low power communication can accomplish.