The Barb-A-Watt was designed by Barbaros Asuroglu WB2CBA (Aka ‘Barb’) as a companion measuring device for his QRP operations, and QRP project development.
The Barb-A-Watt overcomes the accuracy limitations of higher power SWR and Power meters when used with QRP power levels and simultaneously measures:
• RF power output from a QRP transceiver.
• RF power to the antenna.
• SWR.
• Power output efficiency; and
• Has a dummy load that can be used to measure up to 15 Watts of RF output power.
This version of the Barb-A-Watt uses a combination of surface mounted devices (SMD’s) and through hole devices (THD’s).
Whilst providing the same functionality as earlier versions the major changes for this version include:
• Replacement of the 9v battery and the 5v regulator, with 2 x AAA batteries and a boost-converter to supply the required 5v for operation.
The increased efficiency of the power supply and battery capacity provides approximately double the battery life of the earlier version.
• Relocating the components on the PCB to enable use of the 2 x AAA battery pack which provides a slimmer (reduced height) Barb-A-Watt.
The Barb-A-Watt is based on the N7DDC (David Fainitski’s) ATU-100 project.
David was kind enough to modify ATU-100 firmware specifically for the Barb-A-Watt to create an accurate RF power and SWR measuring device at QRP levels.
The power meter is rated at 20 Watts when connected to an antenna or external load, however the internal dummy load is limited to 15 Watts.