WSPR_TX_LP1 Transmitter

The WSPR-TX_LP1 is a standalone all band WSPR transmitter with built in GPS for the radio amateur experimenter.
Some quick features:
1: Standalone operation, PC required for configuration but not for operation.
2: Works on any Ham band from 136kHz to 70MHz
3: Is powered from 5V.
4: Pre-built and tested except for the output low-pass filter that needs to be built by the user.
5: Comes with built in GPS module and included external GPS antenna.
6: Set up your call-sign and apply power and off you go!
   Timing and Maidenhead position is automatic from the GPS network.
   Take it camping, move it to another QTH, use it mobile.
   Needs only 5V 250mA so can be powered from a phone charger or USB power pack.
7: Open source software and Schematic is published on Github.
Low-pass filters sold separately
The WSPR-TX_LP1 works on any Ham band from 136kHz to 70MHz and is powered from 5V.
Once you have set up your call-sign it will operate independently indoors or outdoors with minimal requirement of interaction from the user.
There is no need to have it connected to a computer, no need to set the time or to interact with it in any way. The WSPR-RX_LP1 takes care of everything needed automatically for you.
The GPS provides the timing necessary to ensure that the WSPR transmission is occuring at the correct time. The GPS also provide the position information needed to calculate the Maidenhead code that is transmitted. This is a great feature as it means the users don’t have to know the Maidenhead grid before getting on the air. This can be very convenient if you take the transmitter to a new location or use it in a mobile application.

The output power around 300mW is in my opinion just perfect for WSPR operation. With a dipole antenna it will give you continent coverage most of the time but when the conditions are favorable it will give you trans-continent contacts so at this power level it easy to see how the daily conditions change.
The input power requirements are 5V 100mA at idle and 250mA when transmitting.
This makes it possible to use a laptop computer, phone charger or a USB Power pack to power it in mobile or stationary operation mode.
What better way to test out your portable antennas than to stick this in your backpack with a USB power pack and try out different antennas or mobile QTHs?
Advanced but not high cost, minimal assembly required by the user.
To keep cost down and to minimize the amount of version I need to build and keep in stock I have not populated the Low Pass filter on the output.
The buyer will have to build this filter to complete the transmitter. Everything else is built, calibrated and tested.
The low pass filter is sold separately, see the shop for options.
For more information including links to the Source code and Schema - see the product page.
The product comes with the board built and tested and an GPS antenna with 3m cable.
Low pass filter and USB cable is not included.


WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Normal transmissions carry a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with S/N as low as -28 dB in a 2500 Hz bandwidth. Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility. To see a live version of the map pictured at top right, click here.

WSJT-X now includes WSPR among its many supported modes. Most operators will be best served by using WSJT-X for WSPR as well as for any of the two-way communication modes.

WSPR 2 is showing its age but is still perfectly usable. It may be especially desirable if you need a lightweight program that runs on older computers. It features a user-friendly setup screen with drop-down selection of audio devices and rig-control parameters, support for compound callsigns, fine selection of the fractional time for transmitting, and a Tune button. A new Advanced setup screen offers optional CW identification and tools for frequency calibration and automated frequency corrections for your radio. Full details are presented in the WSPR 2.0 User's Guide. Binary installation package is made available for Ubuntu Linux (versions 8.10 and later), Debian 5.03, and other Debian-based 32-bit Linux distributions.

WSPR 2.11 and WSPR 2.12 include these enhancements over WSPR 2.0:

  • Support for software-defined receivers and transceivers that use complex (I/Q) sampling, such as the popular SoftRock kits.
  • FMT, a package of command-line programs designed for use in the ARRL Frequency Measuring Test and similar frequency-measuring tasks.


WSPRlite Classic Antenna Performance Analysis System

Wondering how well your antenna works? WSPRlite with DXplorer will tell you...

The WSPRlite is a special test transmitter that sends a signal to a Worldwide network of receiving stations. When used with our web-based DXplorer system, it's a powerful new way to evaluate antenna performance. Going way beyond antenna modelling or antenna analyzers, this unique system allows you to see how your antenna is performing in its actual location and in real-time! This type of analysis has never been possible before.