Matching bad antennas

 With QRP a good antenna can often help.  At the same time many rigs lack tuners. 

Amateur Radio Weekly reminded me that a 6dB attenuator drops the power 4 times but always ensures that the load seen by any PA is always less than 1.67:1.  

If you can accept this loss and the attenuator is suitably rated, this may be an acceptable solution e.g. for WSPR beacons.

Attenuators

To get to 10mW I shall probably run my FT817ND at 500mW, and add an attenuator right on the output of the rig. The attenuation needed will be 500/10 i.e. 17dB. There are several calculators on the internet. Using the FT817ND will allow me to declare the correct output power.

See https://www.everythingrf.com/rf-calculators/attenuator-calculator as an example.

Six continents on 10m WSPR

This afternoon I exchanged WSPR reports with RI1ANF in the South Shetland Is in Antarctica on 10m. This now means I've had reports this year from every continent on the 10m band using 5W or less with the wire halo antenna.

PA1B's power attenuator calculator (see link below)

As this is all getting rather too easy (!) maybe I need to follow Bert PA1B's advice and build a switchable attenuator so I can repeat the challenge with much lower powers. See his power attenuator design page for details of how to make suitable RF attenuators to reduce QRP rig output powers to milliwatts.