There are plenty of battery operated QRP transceiver kits on the market these days. But there's something different about the 1-der-40 recently announced by Dwight Morrison, KG4HSY. His kit is battery powered, but it uses 11 batteries, including 10 to provide the 90 volt HT line !

"One dual triode does all the work. In receive, one section of the tube is a regenerative detector. The second section is an audio amplifier which provides good volume to crystal earphones. In transmit, one section of the same tube is a crystal oscillator. The second section is a RF amplifier. A neon bulb provides side tone. The only solid state devices are 3 diodes and the transceiver would work without those. In receive, you can tune up or down from your transmit frequency by approximately 25 KHz. Output power is about 200 milliwatts, more or less, and is routed through a harmonic filter. The transceiver is battery powered using one D cell and ten 9-volt batteries. Voltage on the key is a safe 1.5 volts so it won't hurt you or your keyer. Sockets are provided for the crystal leads for easy crystal switching.

When used as a regenerative detector, many tubes are microphonic and the 3A5 used in this transceiver is no exception. It's not much of a problem unless the transceiver is subjected to vibration. This transceiver does re-radiate when in receive mode and in regeneration. This is typical of all regenerative type detectors where no buffer stage is employed between the antenna and detector. The amount of re-radiation is kept to a minimum by a very low amount of coupling between the antenna and the regenerative detector, but it is still possible to cause interference to other receivers operating nearby. Because of the chance of interference, I don't recommend that this transceiver be used at group functions where others are operating nearby."

More details can be found at the Glowbug Kits website.