Transmitter; Class E Pa Finals; Figure 139. Schematic Of Class E Transmitter - NORCAL NC2030 Manual

The post filter LO amplifier is a configured as a cascode amplifier with a high impedance FET input.
The 10K gate resistor is simply provided to provide a termination for the filter. The output is 1 to 2v pk-
pk. A diode detector is provided to help the user in the filter tune up process.
The receiver does not use a 4x clock, as several versions in the past have done. The detector uses two
phase shifted 1x clock inputs for switching the detector outputs. One clock line is a direct output of the
LO amplifier, the second clock signal is a phase shifted copy of the first. This second signal is phase
shifted by 90 degrees using a pi type C/L/C filter section. This phase shift section was used to minimize
the receiver current drain, as the preferred implementation, the use of a 4x clock and a 4x divider
requires a significant amount of power. The trade here was decreased power, but at the cost of a less
consistent opposite sideband rejection across either the 20 or 30m band.

Transmitter

Figure 139. Schematic of Class E Transmitter

Class E PA finals

The gates of the PAs three BS170 MOSFETs are driven with a 5v square wave produced by a single
74ACT00 gate. The final is capable of 5w output. The power output is not adjustable and is dependant
upon the supply voltage. 14v should produce just over 5w, while 7v will produce roughly1.5w. The
30m version produces less output power than the 20m version due to reflections between the BS170
gates and the driver producing an imperfect drive waveform that is worse at 30m than at 20m.
The first C/L/C elements between the BS170 MOSFETs and the 10T broadband transformer are the
elements that define class E operation. The values listed above are for 20m. Because of the new FCC
regulations on harmonic suppression, a seven element low pass filter is used to make sure the transmitter
has proper harmonic suppression.
Norcal NC2030 v5 12-18-05
Page 121 of 128