I’ve had a couple of people ask about reduced RF output when using the PicoKeyer with a Pixie type rig. When using the on board 3V lithium cell to power the PicoKeyer, slightly less than the battery voltage will be supplied to the gates of the 2N7000 keying MOSFETs. At such low gate voltages, the 2N7000 will only conduct a few milliamperes of current. This is fine for most rigs that use an internal transistor for keying. However, the Pixie and some other small rigs use the key as a switch to turn power on and off to the RF power amp directly. The resistance of the output transistors is enough to affect the output.
One easy solution is to use a different power source. A 1K Ohm resistor and a 4.7 V Zener diode is supplied with the kit; these will let you power your PicoKeyer from an external DC power source such as a 9V battery or 12V power supply. If you have a source of regulated 5 V DC, you can use that instead. This will allow the 2N7000s to turn more fully “ON”, and give your Pixie its full power output. If you opt for an external power source, just be sure you do NOT have the battery connected at the same time.