The WSPR Gizmo

by Jim Cluett

A couple of days ago I built a neat WSPR gizmo
designed by Jay, W5OLF. It's a stand-alone
WSPR beacon that transmits 1.2 watts on 30 meters.
Yesterday morning (on my third transmission) my signal
was heard by VK2DDI in New South Wales, Australia.

WSPR is an acronym for Weak Signal Propagation
Reporter. Each transmission lasts for 2 minutes
and contains a callsign, grid square, and power.
Stations around the world decode signals 24 hours
a day using software defined radios and the results
get posted to the internet.

Normally to transmit WSPR, you need a computer and
a SSB transmitter. But W5OLF's gizmo is a complete
standalone setup. It measures about 3.5 inches long
and one inch wide. It has about 25 components and
takes an hour to build.

The neat thing about WSPR is it has a 15 db gain over CW.
It's possible to decode signals that you can't even hear...
signals that are below the noise floor.

After building the little rig, I connected it to an antenna.
I was heard by 3 stations in England, a station in Venezuela,
and a station in Belgium. Later that evening I was heard
in France, Alaska, England and Holland. On my third
try the next morning, I was heard in Australia. I was
using a 65 foot piece of wire out a 2nd story window to
an oak tree. The wire was about 25 feet off the ground.

This evening I am amazed. I hooked up the gizmo to an indoor
30 foot wire with a tuner. I ran the wire along the ceiling.
I ran 1 watt and was heard in Colorado, Ireland (4646 km),
Italy (6100 km) and England (5061km).

To find out more about WSPR, just google wspr. Signals
heard are reported at

You can order the wspr beacon from
for $55.