This 50W Power Amplifier kit has no Surface Mount Components (SMD) to solder. A suitable power supply e.g. 20V 5A is required to be able to achieve the full 50W output - refer to the manual. It is designed to be driven by a standard QCX CW transceiver kit (QCX powered by a 12V supply). A key feature of the kit is the solid state fast transmit/receive switching which provides full break-in (QSK) operation (hearing the band between your own dit and dah keying). This amplifier is not intended to be a Linear (for SSB use) - it is designed for single-band CW operation only.
The design uses only low-cost, commonly available components such as the pair of IRF510 in push-pull as the power amplifier transistors, and 1N4007 as the PIN diodes for transmit/receive switching. If you damage any components such as the IRF510 transistors, they are easy to source and replace.
Please refer to the FAQ at http://qrp-labs.com/50wpa for any questions.
The enclosure is custom-designed and manufactured specifically for this 50W PA kit. It has top and bottom sections made from black anodized extruded aluminium, with front and rear panels drilled, cut and printed for the PA kit LEDs and connectors. The top half of the enclosure is drilled to fit the heatsinks supplied with the kit. See photos section below for some pictures of the enclosure.
OPTIONAL enclosure kit contents:
Comment from designer Hans G0UPL:
"During the summer of 2019 the 40m version of this amplifier was tested extensively here in QTH KM46, with well over 500 QSOs in the log. Despite the poor band conditions and my very mediocre antenna and location, QSOs ranged from New Zealand and Japan in the East, to US in the West; Finland in the North, down to Saudi Arabia and everywhere in between. (500+ real QSOs averaging 10 minutes, not contest exchanges). During QSOs I estimate around 90% of correspondents are using power in the 50-100W range, the remaining 10% operate with higher power than that or a few of them, with QRP (5W and below). This 50W PA kit puts you and your QCX on a level playing field with the majority of CW operators on the bands."
Hard-copy assembly instructions are not included in the kit. You need to download the assembly and operating instructions manual from http://qrp-labs.com/50wpa
MORE DETAILS are at http://qrp-labs.com/50wpa