2007: The Hendricks QRP Kits Two-fer

The Two-fer, a classic QRP transmitter introduced in 1986 by a team of developers from QRP Amateur Radio Club International, has made a comeback in kit form thanks to Dos Palos, CA-based Hendricks QRP Kits. Details about the Two-fer, its contruction and performance can be found in the QRP column of the July 2007 edition of WorldRadio magazine. For details about price, ordering and shipping, visit the Hendricks QRP Kits website. For an enlarged view, doubleclick the image.

1987: K4AHK's Two-fer, Part 1

Bill Harding, K4AHK, of Burke, VA shared this rare photograph of QRP Amateur Radio Club International's Two-fer 40-meter QRP transmitter kit from 1987. It was a project dreamed up by a group of club members headed by John Collins, KN1H, at the 1986 Dayton Hamvention. The Two-fer is one of QRP's classic rigs, which last year celebrated its 20th anniversary. For an enlarged view, doubleclick the image.

1987: K4AHK's Two-fer, Part 2

A second photograph of the Two-fer transmitter provided by K4AHK, shows the transmitter sharing chassis space with an accompanying receiver and transmit / receive switching circuitry. For an enlarged view, doubleclick the image.

1987: Building instructions, Part 1

Opening with the words, "Welcome to the exciting world of QRP operation," QRP ARCI's Two-fer transmitter kit's building instructions took homebrewers in 1987 through step-by-step assembly of the rig. "These instructions assume you have had some type of experience in building electronic projects," the club warned. "The Two-fer is not a Heathkit." The instruction manual was generously offered for viewing to visitors of The QRPer by Bill Harding, K4AHK, a key member of the Two-fer kit's development team in 1986. For an enlarged view, doubleclick the image.

1987: Building instructions, Part 2

The second page of building instructions for the QRP ARCI Two-fer transmitter took the homebrewer through the final stages of construction. It also included a complete parts list and a recommendation of where the builder might obtain a quartz crystal to determine the rig's operating frequency on 40-meters. For an enlarged view, doubleclick on the image.

1987: The Two-fer kit schematic

The schematic for QRP ARCI's Two-fer transmitter showed what made this little rig tick: an MPF102 variable crystal oscillator followed by a 2N2222 buffer stage driving a 2N3553 final amplifier. A 2N3906 was used as a keying transistor. Of course, the rig's design two decades ago met FCC regulations for spectral purity at the output. But that would not be the case today. For an enlarged view, doubleclick on the image.

1987: The Two-fer Board

QRP ARCI's Two-fer kit manual - circa 1987 - included a detailed diagram of parts placement on the rig's printed circuit board. It was an appreciated feature for homebrewers who were dabbling for the first time in solid-state / PC board construction. For an enlarge view, doubleclick the image.