The MilliWatter Extreme will let you explore the amazing potential of extreme QRP “QRPp”. The MilliWatter Extreme is an RF-switched transmitter-attenuator that opens up the world below 1 Watt. These low power levels are not available for many transceivers. Few power meters are accurate at these levels either so the MW Extreme opens up a new world of challenge; a world that is inaccessible for many transceivers used for QRP.

Because the MW Extreme’s attenuators are RF-switched, you retain full receiver performance – essential for the higher HF bands. The MW Extreme has an adjustable hang-delay time for convenient use on different modes.

Using the MWEXTREME is much more convenient than using conventional attenuators, especially for the multi-band MilliWatter who needs to tune an antenna on band changes. With the MilliWatter Extreme you can tune on full power at the flick of a switch and then immediately join the fun on QRPp.

The MilliWatter Extreme gives you two accurate new power levels: 1/10th power and 1/50th power. We spent a lot of time designing the attenuators to give exceptional performance across the entire HF band.

The following examples show the power levels the MWEXTREME opens up for you:

  • Input power 5 Watts, output (low) 500 mW, output (extreme) 100 mW.
  • Input power 2 Watts, output (low) 200 mW, output (extreme) 40 mW.
  • Input power 1 Watts, output (low) 100 mW, output (extreme) 20 mW.

You will be amazed at what can be done with such extreme QRP. Set yourself some new challenges, worked all states or worked all continents on 100mW perhaps?

The MilliWatter Extreme gives you three convenient power levels at the touch of a switch “full”, low and extreme.

The MilliWatter Extreme is also great for WSPR and datamode experiments. It can also be used to reduce power for transverter drive.


Power is supplied by a standard USB socket (5 Volts), just hook it up to your shack computer or any USB charger. Lead not supplied – any USB-B printer lead will do.


Through loss < 0.15 dB
10 dB attenuator +/- 0.1 db 0 – 30 MHz
17 dB attenuator +/1 0.15 dB 0 – 30 MHz
Maximum power input 10 Watts

BOXA Products

All BOXA products are available in three configurations:

1. Board kit: a high quality PCB with all on-board components.
2. Board kit plus enclosure: adds a high quality rugged extruded aluminium enclosure complete with laser-cut front and back panel. No drilling, no metalwork needed!
3. Fully built and tested: the complete product with enclosure, built and tested at our factory. Ready to use.

Price: €26.76 (inc Tax)