WSPR Station

Project 5 of 7 for October, 2020 – projects to keep sane during Covid-19 Lockdown

Status: Completed and on the air as of June, 2021

WSPR has been played with for so long it has gone through may iterations. As of May, 2022, the latest attempt is to use a TAPR WSPR board on a Raspberry Pi. This runs 200 mW on one designated band. In our case, 10 meters. Watch for progress. Continue reading below to learn about earlier attempts.

The object of building a WSPR station is to be able to see signals first hand real time that are coming into this qth. A band to operate on can be chosen more quickly and more efficiently. WSPR per se is explained here:

While it would be great to have a WSPR transmitter as well as receiver that is not feasible at the remote site or at home. The radiated signal from WSPR would cause interference to other services. A reasonable alternative exists and that is to receive only. Stations decoded will be posted to which shows a map of where those stations are located.

Hardware and software is about as simple as it can get. All parts are already in place and just need to be connected and configured. A computer that is already on site can run the WSJT-X software. An antenna that is already on site, the DXEngineering RF-PR-1B Active Magnetic Loop, can provide a signal on multiple bands. A receiver that will work well is the SDRPlay. The new model RSPdx is on site and is an excellent choice because of it’s additional bandpass filter on the low bands. It will enable monitoring of 630 meters all the way up to 10 meters. Virtual audio channel software will need to be installed to provide a software connection between the SDRPlay and the WSPR decoder. Virtual com port software will be needed for cat control to change frequencies. Power budget will be low because the pc and the receive loop already run 24 hours a day. The SDRPlay is the only additional power draw and it is insignificant. It plugs into a usb port on the pc and draws power from the pc.

Updates to follow as the project is implemented. Example display of is below.

It’s working! Check it out at Running on 30 meters alone provides this result.

All it needed was to reload SDRUno with the latest version, vspn port emulator software, and vb basic virtual audio cable software. A YouTube instruction video by the SDRPlay technical department helped a lot.

Final step will be to open up all bands, not just 30 meters. That works but the whole WSPR operation is not at all stable. This project is not done. It is stable so long as it is not disturbed but accessing the pc with remote desktop. That disturbance stops the WSPR operation.

It has been stable for more than a day by starting the applications on site and not using remote desktop. This is not a solution because we need remote desktop to reach other applications. Work in progress.

Currently working on an antenna on the house back in Denver to become the beacon antenna. How long before the HOA notices?

Update – June, 2021: Relocated to the site of the remote base, using Hustler 6BTV vertical antenna and Yaesu FT-817 transceiver. Running 1 watt on 80,40,30,20,15,10, and 6 meters. The computer is an Intel NUC i3 running Windows 10 and WSJT-X 2.4.1. Here is a typical example of performance. The best spot is Iceland hearing W0QL with it’s 1 watt and a vertical.

Above is an example of 30 meters early one evening. One watt and a vertical is amazing.

WSPR Station

The Solar Eclipse QSO Party urges, “Operate a wide-band automated receiver at your station” like a wspr station.  The station has been in staging at home before it gets deployed to the permanent site in Strasburg but not working correctly.  Finally a breakthrough.   Today we figured out a problem.  Now we’re seeing our wspr station being spotted on, running only 1 watt and feeding a Hustler mobile whip antenna.

Screenshot 2017-07-23 19.54.16

This is the Hustler mobile antenna getting that big 1 watt signal around the country.


The WSPR station being staged before deployment looks like this.

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The computer is an Intel Compute Stick, on the left side half way up running Windows 10 and WSJT-X version 1.8.  The red box is a West Mountain Radio PlugNPlay Rig Runner to interface to the Yaesu FT-817.  The yellow candy wrapper is shrink wrap around a dc-to-dc converter.  It takes in 12 volts dc and converts it to 5 v dc for the powered usb hub and for the Intel Compute Stick.  Green and blue plugs from the PlugNPlay go into an external usb sound card.  One of the usb dongles is a Yaesu CT-62 CAT interface cable.

Deployment plans include packaging the above apparatus into a fiberglass outdoor enclosure, then adding a solar panel, controller, and batteries.  The permanent antenna will be a Cushcraft AP8A trap vertical picked up at a recent hamfest.  The complete 12 volt station draws 1.3 amps when transmitting (at 1 watt) and draws .6 amps when receiving, including the computer. Can’t use an automatic tuner because wspr changes bands and listens before transmitting.  That means the tuner is still tuned to the previous band instead of the current one.  Must use resonant antennas like trapped vertical.

We’ll turn on band hopping and cover 80 through 10 meter bands.  If we get the ambition we’ll add a 6m vertical stub and cover that band, too.  This project is targeting the August 21, 2017 solar eclipse.  In addition to WSPR we plan to operate the Solar Eclipse QSO Party using weak signal modes JT65, JT9, and FT8 on the main station. We’ll be receiving on 630 meters and transceiving on 160 through 6 meters making as many QSO’s as we can.

First plan went out the window because a trapped vertical needs radials and the weeds  make that impossible.  Plan B is to try a Comet CHA250B because it requires no radials.  It just didn’t get a signal out. Out the window.  Plan C is to receive only at Strasburg and transmit only from home.  Can’t receive from home due to a high noise level.  But at Strasburg  when unchecking all the transmit boxes in wspr it no longer band hops.  Is this a bug?

A solution popped up while reading the manual to try to see why it stopped bandhopping.  There is a “tune” checkbox that sends unmodulated carrier for a few seconds after changing bands.  We just happen to have the ideal tuner — a SGC SG-211.  We’ll try that next.

The SG-211 failed because it needs more than a watt for tuning.  Next we tried a LDG RT-100 and it worked perfectly.

Update, September, 2022 —  Zachtek WSPR Transmitter is discovered and solves the problem.  See QST, September, 2022, ZachTek WSPR Desktop Transmitter, page 44.  “The ZachTek WSPR Desktop Transmitter is a standalone multiband WSPR transmitter that contains its own WSPR firmware, so it does not require an external computer and software to operate.  Although it’s a low-power transmitter, you will be surprised how far you can get with it — even mobile!”.  The transmitter was ordered, arrived a week later, and was installed.      

For an antenna, the Hustler 6BTV that was originally purchased for WSPR in 2017 was called upon. Part of 6BTV installation is carefully tuning each band to the WSPR frequency for that band.

The ZachTek has been in service since early September, 2022 and the results are quite impressive as demonstrated by the late morning screen shot below.

It runs on 5 volts and is very reliable so far. There is one issue, however, and that is rf interaction with the main station. When the main station is transmitting on 40 meters the ZachTek crashes, even with a lot of toroids on the leads. It recovers with a reboot. This issue was solved by installing a relay to turn off the ZachTek whenever the main station is turned on. When the main station is turned off and the ZachTek is turned back on, it reboots automatically and begins transmitting again. All settings are preserved each time and does not require manual intervention. Missing out on WSPR while the main station is running is very frustrating when the main station is running for a long time. An alternate solution is needed.

Commentary. At any given moment in 2022 there are more stations on FT8 than on WSPR or any other beacon network. The shear quantity of stations operating FT8 outnumbers the number of WSPR stations and therefore provides more information. As good as WSPR is, PSKreporter may be better because it shows a broader picture of propagation. Take a look at PSKreporter for the same time and draw your own conclusion. PSKreporter is configured to display the local grid square, all bands, all modes, for the past 15 minutes.