Weak Signal Propagation Reporter(WSPR)

• WSPR is a soundcard (digital) mode designed to check propagation conditions.

• Unlike DX beacons, which tell you only what stations you can hear, WSPR also tells you what stations can hear you.

• WSPR uses low-power signals, under 10 Watts. In the WSPR community, “QRP Operation” refers to power levels <500 mW.

Why Use WSPR ?

• Learn something new.

• It helps amateurs around the world understand signal propagation. www.wsprnet.org

• It helps you predict where your signal can be heard & look for band openings.

• It allows comparison of antennas.

• Success depends on participation.

Fc Suppressed Carrier Freq.

Freq. (Hz)Fc + 1400 Hz Fc + 1600 Hz

WSPR Transmissions - 6 HZ BW

WSPR transmits a USB, suppressed-carrier (SSB) signal.

Each transmission is 4-tone FSK, with a 1.4648 Hz tone separation.

The transmitted signals are in a frequency range from 1400 to 1600 Hz above the carrier frequency.

Each signal occupies an approximately 6Hz bandwidth.

WSPR can decode signals 28 dB below noise in a 2500 Hz noise BW.

A transmission consists of your call sign, your 4-character grid square, and your power level in dBm. Each transmission period is 2 minutes long.

(0 dBm = 1mW; 30 dBm = 1W; 37 dBm = 5W; 40 dBm = 10W)

WSPR Signal Format

What You Need

• HF Transceiver – crank down power to 10W or less.

• Computer with a soundcard connected to the transceiver. 1.5GHz min CPU speed. Computer clock must be synchronized to UTC. Soundcard should have 48KHz sample rate or better.

• WSPR software (free) – download from www.physics.princeton.edu/pulsar/K1JT/wspr.html

• Important – Download the user’s guide as well !

Soundcard Interfacing

Contrary to popular belief, you don’t need to use a fancy soundcard interface. It can be as easy as directly connecting the soundcard to the radio:

But -

Commercial (or homebrew) soundcard interfaces can provide better isolation between the radio and computer and better PTT control to prevent Windows sounds from causing unwanted transmissions. Try direct first w/ VOX.

From: http://ve3elb.ham-radio.ch/soundcard%20interface.html

Start here : www.physics.princeton.edu/pulsar/K1JT/wspr.htmlDownload software & user’s guide.

WSPR Frequencies

• Frequencies:• USB dial (MHz): 0.5024, 1.8366, 3.5926,

5.2872, 7.0386, 10.1387, 14.0956, 18.1046, 21.0946, 24.9246, 28.1246, 50.293, 144.489

• The frequencies are listed on the www. wsprnet.org webpage. Also set automatically by the software.

Where to Start

• Install the software.

• Connect the transceiver audio in/out to the soundcard. Try receiving first.

• Start WSPR. Tune the receiver to the correct WSPR frequency. Use CAT control if you have it.

• Have some coffee and wait a while. You should see (& hear) something like this:

Transmission / reception intervals are every two minutes, starting on the even minute. Xmit frequency is set by a click of the mouse.

What if it doesn’t work?(You hear signals, but nothing decodes.)

• Check the setup of the Windows mixer – make sure that the Line Input is enabled.

• Be patient – remember it takes 2+ minutes (after the start of transmissions) to decode anything.

• Make sure that the receiver is tuned to the correct frequency.

• RTFM – Check the User’s Guide, especially Appendix C.

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. www.wsprnet.org

Go to www.wsprnet.org & Click on Map to see activity

KD5SG Activity for 30 Minutes on 20 Meters Dec 27, 2010

Previous map expanded for clarity. Click on any call sign to see details.

30 Meter Activity, a few days later. Map can be “zoomed” as needed.

Maps can be customized by Call, Band, and Time Period. You can leave the call sign blank, and set the band to “All” to see everything, But the map takes longer to load !

Misc. Soundcard Interfacing Information:

 

“Understanding Soundcard Interfacing” by WM2U : http://www.qsl.net/wm2u/interface.html

 

“Soundcard Basics for MARS Stations”: http://navymars.org/central/reg4/al/basics.htm

 

“Buxcom Handbook”: http://www.nonstopsystems.com/radio/pskhandbook.pdf

 

“The Ins and Outs of a Soundcard” by K1UHF, QST, October 2003:

http://www.westmountainradio.com/pdf/Ins&Outs.pdf

Note: Many soundcard interfaces use an optoisolator to control the PTT function. The Optoisolator family (4N29 to 4N33) is not recommended since some PTT circuits may not switch properly due to the high saturation voltage of the Darling output transistor. The Avago Tech. FET output, optically-coupled relay (#ASSR-1219-001E) from Mouser Electronics is a better choice.

 Commercially made interfaces are available from West Mountain Radio, Tigertronics, MFJ, and others.

 

What’s Next ?

Work the world !

Try WSJT (JT65) for HF QRP confirmed QSO’s.http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html