A600 HF/VHF 600W linear amplifier kit v1.2

(1 customer review)

HF/6m Linear LDMOS Amplifier Kits has information about the latest version of this kit.

  • Over 600W from 1.8MHz to 54MHz
  • 24dB typical gain, needs less than 3W drive
  • High efficiency, typical draw 20A @ 44V.
  • Onboard sensors for supply voltage, instantaneous current draw, heatsink temperature, forward and reflected RF power
  • Connectors for a separate Low Pass Filter bank
  • Compact size, just 190x100mm
  • Includes copper heat spreader
  • NXP Homebrew RF Design Challenge award winner

Images are showing the v1.0 design, all improvements will be described in the documentation. This is a kit and requires assembly, heatsink is not included. See more details here and here.

SKU: A600KITv12 Category:

No longer available. Has been replaced by an improved version:

A600 HF/VHF 600W Linear Amplifier Kit


The A600 v1.2 is an improved version of the original A600 design that was awarded 2nd place in the NXP Homebrew RF Design Challenge 2019.

Improvements include separate chokes for feeding DC to the power transistors drains, improved overall gain and gain flatness, improved input matching (under 1.5:1 across the whole frequency range) and readjusted the bias circuit for more accurate thermal tracking.

This is an Advanced level kit and assumes you have a good understanding of electronics. The PCB is supplied with the surface-mount components already installed, but some of the parts supplied in this kit will require assembly and soldering. You will also have to source a power supply and a large heatsink, drill and tap the heatsink (and included copper heat spreader) and build your choice of input-output switching circuitry. Recommendations are included in the provided Assembly Instructions.

The Sensor Port provides sensor outputs for measuring circuit parameters such as supply voltage, supply current, heatsink temperature, forward power and reflected power. They are all analog signals in the 0-5V range and can be easily interfaced with a microcontroller of your choice (eg: Arduino) to implement display or protection routines. The signals are described in the provided Assembly Instructions.

To use this amplifier on the air and meet legal requirements, it is recommended you use a bank of switchable Low Pass Filters and make sure you don’t overdrive it beyond the design output power.

1 review for A600 HF/VHF 600W linear amplifier kit v1.2

  1. Neal Obert

    Looking forward to pricing on this kit. Will purchase asap.

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  • Output power (P1dB): over 600W from 1.8MHz to 54MHz
  • Gain: 24dB typical, drops to 22dB on 50MHz
  • Supply: 44V @ 20A typical, 48V/25A recommended
  • Heat spreader: copper, 100*100*3mm
  • Connectors: SMA for RF signals, screw terminals for PSU, 2.54mm spaced header for sensor port
  • Size: 190x100mm
  • Heatsink: not included, 0.1C/W or better recommended

Kit contents

  • 190*100mm PCB board with installed SMD parts
  • Pair of MRF300AN & MRF300BN LDMOS RF power transistors
  • All required through-hole parts in separate bags
  • RF transformers & inductors in separate bags (require winding)
  • Undrilled 100*100*3mm copper heat spreader & stainless steel M3 and M4 bolts
  • Assembly instructions

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