What is WSPR?
Steve Nichols G0KYA
www.qsl.net/g0kya
Steve Nichols G0KYA, RSGB Propagation Studies Committee
What is WSPR?
• The Weak Signal Propagation Reporter
• An automated system designed for sending
and receiving low-power transmissions to test
propagation paths on the MF and HF bands.
• The program can decode signals with S/N as
low as -28 dB
Steve Nichols G0KYA, RSGB Propagation Studies Committee
What is WSPR?
• WSPR was designed
and written by Professor
Joe Taylor K1JT.
• A Nobel prize winner
and inventor of WSJT,
JT65 and others.
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How does it work?
• Your system transmits a
(just under) two-minute
long FSK signal with a
6Hz shift.
• The signal contains your
callsign, locator and
power level in dBm.
• And then it listens ....
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How does it work?
• Your system listens for WSPR signals, in a
200Hz passband, decodes them and lists
them in the software.
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How does it work?
• The computers
then send their
results to
www.wsprnet.org
where they are
stored and
displayed.
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How does it work?
You also have a visual display ...
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How does it work?
... that you can customise by band/time/call
Steve Nichols G0KYA, RSGB Propagation Studies Committee
What do you need?
• A PC running Windows * with an accurate
clock and an internet connection (not essential)
• The WSPR program
• A data interface (such as used for RTTY)
• An HF (USB) rig and antenna
See http://www.g4ilo.com/wspr.html
* Can be compiled for Windows, Linux, FreeBSD, Macintosh OS/X, and most other Unixlike operating systems
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Things to watch out for
• Set the power output in dBm carefully!
(5W = 37dBm)
• You don't
need to run
more than
10W (40dBm)
– some run
1mW (0dBm)!
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Things to watch out for
• Set the right frequency (USB)
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Things to watch out for
Set correct
time
Tick to
upload
spots
Set correct
frequencies
Don't let it
go red
(+/-10dB)
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Set to
20%
WSPR QSO mode
Joe Taylor: “There is a 'WSPR QSO mode' in
WSJT. This mode has not become popular, I
think in large part because the data rate is
too slow and the 50-bit messages too
constrained.”
WSPR QSO should operate near the normal
JT65 QSO frequencies - 14.076500MHz
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How has it grown?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
How has it grown?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Do WSPR contacts count
for DXCC?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Do WSPR contacts count
for DXCC?
Bill Moore NC1L, ARRL Awards Branch
Manager: “From what I read it appears that
this is just another digital mode and for
DXCC it would count as RTTY.”
Steve Nichols G0KYA, RSGB Propagation Studies Committee
So what can you work/hear?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
So what can you work/hear?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
So what can you work/hear?
Just half an hour on 30m with 5W to a mag loop in the rafters
Steve Nichols G0KYA, RSGB Propagation Studies Committee
So what can you work/hear?
30m
5W +
MFJ mag
loop in
loft
Steve Nichols G0KYA, RSGB Propagation Studies Committee
So what can you work/hear?
30m
5W +
MFJ mag
loop in
loft
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Can it “hear” better than
CW?
“WSPR is about 11 dB better than ear-andbrain CW.
“For most operators, the difference is more
like 15 dB."
Steve Nichols G0KYA, RSGB Propagation Studies Committee
What can you do with
WSPR?
• Look for fleeting/rare propagation paths
eg Sporadic E on 10m
• Test antennas
• Do long-term propagation research
• Have fun!
Steve Nichols G0KYA, RSGB Propagation Studies Committee
What are the downsides?
• Not enough stations on – often only 2-5 on 10m
• People don't put in the correct locators/power
levels
• People “come and go” making long-term research
difficult
• Data format not conducive to graphing
• WSPR reports signal to noise ratio, not signal
strength.
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Mistakes/errors/bad decodes?
YA1YOU – Afghanistan
in HB14 square??
I don't think so!
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Mistakes/errors/bad decodes?
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Mistakes/errors/bad decodes?
WSPR may be prone to bad decodes on
slow machines c400-500MHz processor.

Local QRM/noisy environments can cause
bad decodes that PASS the forward error
correction tests.

Steve Nichols G0KYA, RSGB Propagation Studies Committee
User error
Reporting captures as being on one band
when they are actually on another.

“I was in a rush this morning, and in my haste I
started WSPR without checking the band. All my
spots for 30m on 2-3 Oct are invalid. I was TX'ing
and RX'ing on 40m.”
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Antenna tests – USA (Stu Philips)
Conclusion: The vertical dipole (right) generates longer
distance spots in more time periods than the inverted L.
Steve Nichols G0KYA, RSGB Propagation Studies Committee
VOACAP v Reality – F6IRF
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Is propagation bilateral? – F6IRF
• K1JT hears F6IRF, but not the other way (look
at maximums) – see http://f6irf.blogspot.com
Steve Nichols G0KYA, RSGB Propagation Studies Committee
High angle at sunrise? – F6IRF
• K1JT louder at F6IRF on vertical mag loop (high angle) at
sunrise - http://f6irf.blogspot.com
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Antenna comparisons – G8JNJ
Tests
completed
on 80m
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Antenna comparisons – G8XLH (1)
Tests
completed on
30m
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Antenna comparisons – G8XLH (2)
Tests completed
on 160m
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Dxpeditions: TY1MS, Benin (10-27 Oct '09)
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Maritime mobile: OE1IFM, Gernot
http://www.oe1ifm.at/
About 2,500 spots on
seven bands in six days.
1W on 80-40-30-20-1715-12
Grado - Jesolo Venezia - Chioggoa Trieste - Izola - Grado
Steve Nichols G0KYA, RSGB Propagation Studies Committee
Conclusion:
• WSPR is a useful tool – probably unsurpassed for
QRP contacts
• As a QSO “chat mode” it is no match for
SSB/CW/PSK31/RTTY
• The spot database is useful, but don't believe all
you see
• It needs more users
• Will it take over from “real radio” - no!
• Find out more at www.wsprnet.org and
http://www.physics.princeton.edu/pulsar/K1JT/
Steve Nichols G0KYA, RSGB Propagation Studies Committee