Fun with WSPR

I have sent out some emails reporting my success and the success of other hams in making DX contacts using unbelievably low transmit power levels.  There was some interest in this so I thought I would briefly provide some background to jump start you.

What is it?

The Weak Signal Propagation Reporter Network is a group of amateur radio operators using K1JT’s MEPT_JT digital mode to probe radio frequency propagation conditions using very low power (QRP/QRPp) transmissions. The software is open source, and the data collected are available to the public through this site.  http://wsprnet.org/drupal/ Go to the website, click on the map tab, select a band (below the map) and take a look at the action.  Clicking on any call sign will show you who is receiving that station and who he is receiving.

Where do I get it?

Program and documentation downloads are available here  http://physics.princeton.edu/pulsar/K1JT/wspr.html

If you have not done this before, read the documentation.  J

When can I start having fun?

First of all, my experience has been that the set-up is really easy and, if you are already working digital modes you can start WSPRing (pronounced whispering) in just a few minutes.

A few tips:

  • Use a rig with a TCXO, good stability and calibration (i.e. check against WWV)
  • Use a rig with CAT control (sorry, that old FT-101 will just give you grief here …)
  • A simple antenna is all that is necessary, of course if you have a big, high antenna results will be  better
  • Install an internet time program in your computer (as per documentation); or go into the Windows time and date and make the clock update once every 15 minutes, or use GPS timing (overkill, but what the heck)
  • If you have a multiband antenna (e.g. an all band vertical, 10-15-20m beam, etc.) you can have more fun.
  • Loop antennas, including magnetic loop antennas that don’t take up much space, work well.  No excuse not to try this mode if you live in an apartment!
  • Please don’t use more than 5 W out.  In this mode QRP starts at 500 mW.
  • I have two screens on my station computer, one showing the WSPR software and the other the map on wsprnet.org

What should I try WSPR?

This mode has given me a much better appreciation of how propagation works.  I found it interesting to watch the signals on a given band change as the gray line approached and then passed overhead.  I learned that a wire antenna and <1 watt can radiate a signal simultaneously heard (from the middle east) both in New Zealand and North America.  I also found out that you can reduce power to ridiculously low levels — I am currently running on 125 mW on 20m and 250 mW on 40 m with good results.   I have “spotted” (i.e. decoded signals from) hams in Europe using 10, 5 and even 1 mW.  The current challenge is to see how far your signals get on 500 micro watts !  (0.5 mW you will need calibrated attenuators in your antenna line to do this).

The ability of the software to dig a narrow band signal out of 30 dB of noise is impressive.  We are lucky to have a Nobel Prize winning physicist (K1JT) writing software for ham radio.

“…to explore strange, new worlds, to seek out new life and new civilizations, to boldly go where no ham has gone before.”

VA6TJ