Hello happy QRPers
Just want to share the QDX PA modification. I want to have the possibility of output power setting.?
The modification just replaces the L14 by some resistor network and switch. There is also a combined 1uF+10nF capacitor from PA transformer center tap to the GND.
I used 3 position switch and some resistor combinations to have the desired output power:
3Ohm (3x 1Ohm resistor) - about 4W output
14.2Ohm (the resistors above -3 Ohm- plus two resistors 5.6Ohm each in series) - about 1W output
64.2Ohm (the resistors above - 14.2Ohm - plus two 100Ohm resistors in parallel) - about 0.1W output
Power measured with the oscilloscope, as such low levels are usually not possible to measure accurately with common SWR/PWR meters.
73
Pawe? SO8FM
