IN3LBQ on the Hühnerspiel (Amthorspitze) - photo by IN3OTD

Amateur radio RF power amplifiers

These pages contains various information about several RF power amplifiers, mainly for the HF bands, that I have built and characterized.
Most of the measurement were done with the automated system described in the automated IMD measurements page, so a standard set of data is usually shown:

Here is a list of the amplifiers characterized so far:

HF QRP power amplifier

Measurements on the QRP Project PA-2008, a 5 W amplifier for the HF bands.

DL2EWN 5 W wideband PA

Measurements on a wideband 5 watt amplifier, designed by DL2EWN.

DL2EWN 1 W wideband PA

Measurements on a wideband 1 watt amplifier, designed by DL2EWN.

Wideband low-power amplifier

A small power amplifier for the HF and VHF bands using a PD85004 LDMOS in class A.

Wideband push-pull low-power amplifier

Another small power amplifier for the HF band using two PD85004 LDMOS in push-pull (class AB).

HF/50 MHz Class A PA

A Class-A simple QRP power amplifier covering the HF and the 50 MHz band, designed by Jim Veatch, WA2EUJ.

Small HF PA drivers

These drivers were intended to drive an HF PA for the Hermes-Lite but could of course be used for others low-power PAs. They cover the HF bands and have an output power of about 20 dBm.
All circuit use an ubiquitous 2N2222A (or its SMD version PZT2222A) and draw about 40 mA at 12 V.

Small HF driver #1

A classical resistive-feedback amplifier with 10 dB gain, 33 mW (15 dBm) output at 1 dB of compression. With a two-tone input, the output is 9 mW per tone for an IM3 of -30 dBc.

Small HF driver #2

Another classic, a lossless-feedback scheme by Norton; 9 dB gain, 200 mW (23 dBm) output at 1 dB of compression. With a two-tone input, the output is 61 mW per tone for an IM3 of -30 dBc.

Small HF driver #3

Another resistive-feedback amplifier, 10 dB gain, 100 mW (20 dBm) output at 1 dB of compression. With a two-tone input, the output is 27 mW per tone for an IM3 of -30 dBc.

Small HF driver #4

A resistive- and transformer-feedback topology by Rohde, 11 dB gain, 160 mW (22 dBm) output at 1 dB of compression. With a two-tone input, the output is 40 mW per tone for an IM3 of -30 dBc.

BS170 PA

The final stage only of the Softrock Ensemble RXTX, using a couple of cheap BS170.