I call the new amplifier the NB6M Miniboots . For those who are comfortable with building Ugly Style from a simple circuit, this project is a snap and the parts are all readily available. For those who would like the parts already gathered and the layout prepared for them, a kit is in the offing. Tests thus far have been very satisfactory on the 80 through 20 Meter ham bands, with output typically 14 Watts or more on 80 and 40, a bit lower on 30, and around 10 Watts on 20. Initial tests on the higher frequency bands indicate that some circuit changes may be necessary in order to provide for operation of the Miniboots on 17 through 10 Meters.
Further tests are in progress.
The additions to the basic QRP Gallon circuit include an RF-sensing relay driver circuit to switch the amp into and out of the antenna line automatically, output network filter values to allow for up to fourteen Watts of output with a two watt input, and a drive level adjustment potentiometer which allows for setting the amplifier at exactly the 5 Watt QRP Gallon level as desired. Mike Gipe, K1MG, performed spectrum analysis tests on a 40 Meter version of the Miniboots , which showed the output of the amplifier to be quite clean at all levels of drive and output. Monitored on another receiver, the output CW note is pure, and the keying very clean. For a driving power level of from one to two watts, the amplifier utilizes a resistive 3db attenuator at the input, in order both to provide a 50 Ohm load for the driving rig and to prevent over-driving the amp. If the driving QRP rig has an output of three-quarters to one watt, a broadband transformer input is used which provides close to a 50 Ohm load to the driving QRP rig without attenuation.