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WSPR Without Tears

Table of Contents

Introduction................................................................................................................................................1
Approach....................................................................................................................................................2
Raspberry Pi...............................................................................................................................................3
What you'll need to complete the assembly...............................................................................................3
Programming an SD Card..........................................................................................................................4

Setup......................................................................................................................................................4
Program SD Card..................................................................................................................................4
Install SD Card into Pi...........................................................................................................................5

Assemble WWoT and Pi............................................................................................................................6
Setup and Adjustment................................................................................................................................7

What You Need......................................................................................................................................7
Getting SSID and Passkey.....................................................................................................................8
Initial Setup...........................................................................................................................................8
Locate the Pi IP Address........................................................................................................................8
Setting WSPR Configuration..............................................................................................................10
Restart Pi.............................................................................................................................................11
Measure RF Output.............................................................................................................................11
IP Addresses........................................................................................................................................12

WWoT Schematic....................................................................................................................................12
Troubleshooting - It Doesn't Work ..........................................................................................................14
Appendix 1 – Communicating With the Pi over SSH..............................................................................16
Appendix 2 – Postprocessing Data..........................................................................................................17

WSPRnet Map.....................................................................................................................................17
Downloading Data...............................................................................................................................19
WSPR Data Filter................................................................................................................................19

Introduction

Thank you for purchasing the WSPR Without Tears transmitter (WWoT). We hope you’ll be pleased 
with it. WWoT is our attempt to put together a WSPR transmitter transmitter that avoids (hopefully) 
most of the problems associated with building a fairly complicated digital mode transmitter. All of the 
information, data and files are accessible through the TAPR website:

tapr.org/kits_WsprWithoutTears

WSPR stands for Weak Signal Propagation Reporter Network. It's a digital mode used by hams. The 
process is similar to a beacon. WSPR is a wonderful communication mode created by Joe Taylor 
(K1JT). WWoT is our attempt at simplifying the process of getting an actual transmitter up and running
so you can enjoy working with WSPR and avoid dealing with the headaches associated with building a 
working system.

TAPR (c) 2018-2019  “WSPR Without Tears”        1 Of 20                                Version 2.1    05/20/2019

Summary of Contents for WSPR

Page 1: ...asing the WSPR Without Tears transmitter WWoT We hope you ll be pleased with it WWoT is our attempt to put together a WSPR transmitter transmitter that avoids hopefully most of the problems associated with building a fairly complicated digital mode transmitter All of the information data and files are accessible through the TAPR website tapr org kits_WsprWithoutTears WSPR stands for Weak Signal Pr...

Page 2: ...of radio A second point the output power of many transceivers can t be adjusted below 5 watts An output power of 5 watts will certainly work but it s interesting to see how little power you can get away with and the useful power range is a lot less than 5 watts The alternative to using your regular station for WSPR is to have a completely separate WSPR station That s a lot more realistic when you ...

Page 3: ...lt but there are quite a few areas that can go wrong and it can be frustrating if you ve never done it before It only takes one problem to kill the whole process There are a lot of steps involved in getting to a working WSPR transmitter We created a version of the software that runs automatically when the Pi is turned on There are several parameters that you the user have to set callsign grid squa...

Page 4: ...r what card reader writer you use It connects your SD card to a USB port 1 Win32DiskImager It s a freebee Download it from tapr org kits_WsprWithoutTears or sourceforge net projects win32diskimager 2 Install Win32DiskImager 3 Disk Image Download it from tapr org kits_WsprWithoutTears file WSPR_Baseline_ where the s are a date This is a big file e g 500 meg 4 Unzip the file after it s finished down...

Page 5: ...it 7 Remove the SD card and install it into the Pi Make sure that power is disconnected from the Pi before doing this If you haven t annoyed the gods of the Internet too much today you should be in luck and everything will work Install SD Card into Pi First insert the SD card into the Pi Figure 2 Inserting SD Card into Pi and Figure 3 SD Card Installed in Pi The SD card sorta slides in up side dow...

Page 6: ...e side from the Pi USB connectors Figure 4 WWoT and Pi Assembly The micro USB power connector is coming out of the TAPR c 2018 2019 WSPR Without Tears 6 Of 20 Version 2 1 05 20 2019 Figure 4 WWoT and Pi Assembly WiFi Adaptor RF Out BNC Micro USB Power Connector Figure 3 SD Card Installed in Pi USB Connectors ...

Page 7: ...he Pi USB connectors are on the right hand side and the WWoT BNC connector is on the left That s how it should be Also make sure that the Pi pins and the WWoT plug are lined up It is possible to offset one from the other so you only have one row of pins connected Setup and Adjustment What You Need I m assuming that you have 1 Assembled Pi WWoT 2 2 amp power supply for the Pi 3 Ethernet cable to co...

Page 8: ...f 2 Connect the Pi to your router with the Ethernet cable This part is a little tricky The Pi has to be connected to a DHCP server That s normally your router It won t work if you plug the Pi into your laptop at least not without some advanced setup Locate the Pi IP Address 1 Working from your PC download WSPR Executables zip file from the web site tapr org kits_WsprWithoutTears unzip the zip file...

Page 9: ...bers for your Pi for the next step That s the IP address of your Pi If the program fails to find the Pi try it again If that fails go to the Troubleshooting section Note The first time you run WSPR_Locater inet addr will be displayed for eth0 the Ethernet connection After setting the WiFi portion of the WSPR configuration see Figure 7 WSPR Configuration Screen WSPR_Locater will display inet addr f...

Page 10: ...WSPR Without Tears Setting WSPR Configuration TAPR c 2018 2019 WSPR Without Tears 10 Of 20 Version 2 1 05 20 2019 Figure 7 WSPR Configuration Screen ...

Page 11: ...o minutes It s considered bad form to flood the WSPR servers with messages The default is to send a WSPR message every ten minutes If you check the transmit every 2 mins checkbox then messages will be sent every two minutes This setting is useful for testing and short term experiments 5 Set the Transmit Power and Transmit Band to 23 dBm and 30m for 30m and 20 dBm and 40m for 40m 6 When all done cl...

Page 12: ...i see Figure 7 WSPR Configuration Screen you will have two valid IP addresses assigned to the Pi Either one will work You probably wouldn t have gone to the trouble of setting up WiFi if you were just going to use Ethernet So now is the time to remove the Ethernet cable Your Pi will now have one IP address There is no advantage to having two IP addresses so you should remove the Ethernet cable if ...

Page 13: ...WSPR Without Tears Figure 8 WWoT Schematic TAPR c 2018 2019 WSPR Without Tears 13 Of 20 Version 2 1 05 20 2019 ...

Page 14: ...tdown button for 2 sec and unplug the power supply Wait for 30 sec and plug in the power supply Wait for the LED s to stop blinking and try to access the web page again If this fails to work there may be a problem with the software load on the SD card 5 Press the pushbutton on the WWoT and hold for two seconds Wait until the LED s on the Pi stop flashing and unplug the power to the Pi 6 Unplug the...

Page 15: ...one significantly lower than the other when transmitting LED on The voltages on both sides of R2 should be about the same whether transmitting or not The voltages at R2 will vary depending on how pot R1 is set The important part is that they re above 0 0 volts and have pretty much the same voltage on either side of R2 If you find voltages that differ significantly from what s listed on the schemat...

Page 16: ...t to talk to your Pi over SSH Actually we sympathize that s our favorite mode for talking to the Pi 1 Download the program KiTTY exe no not a cat as part of the WSPR Executables from tapr org kits_WsprWithoutTears or from http www 9bis net kitty page Download 2 Get the IP address of the Pi from WSPR_Locater 3 Run the KiTTY and enter the IP address for the Pi This will open a command window 4 Usern...

Page 17: ... and click on Map in the upper right hand corner WSPRnet Map Scroll down to the bottom of the graph and change Band as appropriate 30m 40m etc insert your callsign change the Time Period to 24 hours click on the Day Night overlay checkbox if you want to see it and then click on the Update button You can pan and zoom to see how far your signal has gotten TAPR c 2018 2019 WSPR Without Tears 17 Of 20...

Page 18: ...hand corner Click on Specify query parameters just below Database in the upper left and change Band to the appropriate band 30m 40m etc and add your callsign Click the Update button TAPR c 2018 2019 WSPR Without Tears 18 Of 20 Version 2 1 05 20 2019 Figure 10 WSPRnet Display Zoom Figure 11 WSPRnet Database ...

Page 19: ...zip format Pick a month that you d like to investigate and click on the word zip We re amused by what can only be described as wishful thinking on the part of the people who put together the web page The writeup at the top says Compressed file sizes range from 1 20MB The compressed files will be much closer to 300 MB and uncompressed go to about 1 4 GB Most of the entries were not information we c...

Page 20: ...program from the zip file 4 Run WSPR_Data_Filter 5 Enter your callsign 6 Click the Open button select the file you unpacked not the zip file and click Open 7 Click the Save button enter a filename to save the output as and click Save 8 Click the Filter button 9 Click the Exit button when processing is done The output can be read into any spreadsheet program e g Excel directly for processing and gr...

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