A WSPR transmission takes 1 minute and 52 seconds. The GPS time and location data is parsed
from the GPS serial data stream at the END of every WSPR transmission. On the first WSPR
transmission after power up, the time may not be accurate. The 27MHz synthesiser reference
frequency is measured and adjusted, in a 4 second period after the end of the WSPR
transmission. Parsing the time and location, and adjusting the 27MHz reference frequency, all
takes place in under 7 seconds. The process is completed before the start of the next WSPR
transmission slot. Nevertheless, you should not configure your kit for continuous WSPR
transmissions in every 2-minute WSPR slot (Frame parameter is 2), which is considered very
antisocial to fellow WSPR operators.
A GPS receiver isn’t essential for WSPR operation but it is highly recommended because it makes
operation more accurate, easy and fun.
During the actual WSPR message transmission, the display shows something like this:
14,097,140 122 2
G0UPL IO90 37
The elements of this display are explained as follows:
14,097,140 Transmission frequency (tone 0)
122 Current symbol is 122 (of 162 symbols making up a WSPR transmission)
2 Current tone being transmitted (one of 0, 1, 2 or 3)
G0UPL Callsign encoded into the transmission
IO90 5-character Maidenhead Locator square, encoded into the transmission
37 Power in dBm, encoded into the transmission
On a PC spectrum display such as the Argo software http://www.weaksignals.com/ WSPR
messages look something like the screenshot below when received locally (or usually worse,
because you probably are over-driving your receiver when receiving your own signal!):
WSPR decoding takes place in the WSPR program by K1JT (see
http://physics.princeton.edu/pulsar/K1JT/wspr.html ). Below is a screenshot showing the WSPR
2.0 screen following reception of a few transmissions (output frequency = 1,500Hz, Frame = 02,
Start = 00).
QCX operang manual, rmware 1.07, manual edit 0.03 25
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