The personal website of Scott W Harden
March 27th, 2021

WSPR Code Generator

WSPR (Weak Signal Propagation Reporter) is a protocol for weak-signal radio communication. Transmissions encode a station's callsign, location (grid square), and transmitter power into a frequency-shift-keyed (FSK) signal that hops between 4 frequencies to send 162 tones in just under two minutes. Signals can be decoded with S/N as low as −34 dB! WSJT-X, the most commonly-used decoding software, reports decoded signals to wsprnet.org so propagation can be assessed all over the world.

WsprSharp is a WSPR encoding library implemented in C#. I created this library learn more about the WSPR protocol. I also made a web application (using Blazor WebAssembly) to make it easy to generate WSPR transmissions online: WSPR Code Generator

WSPR Transmission Information

  • One packet is 110.6 sec continuous wave
  • Frequency shifts between 4 tones
  • Each tone keys for 0.683 sec
  • Tones are separated by 1.4648 Hz
  • Total bandwidth is about 6 Hz
  • 50 bits of information are packaged into a 162 bit message with FEC
  • Transmissions always begin 1 sec after even minutes (UTC)

Resources

Markdown source code last modified on September 12th, 2021
---
Title: WSPR Code Generator
Description: An online resource for generating encoded WSPR messages
Date: 2021-03-27 8PM EST
Tags: blazor, amateur radio, qrss
---

# WSPR Code Generator

**[WSPR](https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software)) (Weak Signal Propagation Reporter) is a protocol for weak-signal radio communication.** Transmissions encode a station's callsign, location (grid square), and transmitter power into a frequency-shift-keyed (FSK) signal that hops between 4 frequencies to send 162 tones in just under two minutes. Signals can be decoded with S/N as low as −34 dB! [WSJT-X](https://physics.princeton.edu/pulsar/k1jt/wsjtx.html), the most commonly-used decoding software, reports decoded signals to [wsprnet.org](https://wsprnet.org/) so propagation can be assessed all over the world.

**[WsprSharp](https://github.com/swharden/WsprSharp) is a WSPR encoding library implemented in C#.** I created this library learn more about the WSPR protocol. I also made a web application (using Blazor WebAssembly) to make it easy to generate WSPR transmissions online: [WSPR Code Generator](https://swharden.com/software/wspr-code-generator)

[![](wspr-code-generator.png)](https://swharden.com/software/wspr-code-generator)


### WSPR Transmission Information

![](wspr-spectrogram.png)

* One packet is 110.6 sec continuous wave
* Frequency shifts between 4 tones 
* Each tone keys for 0.683 sec
* Tones are separated by 1.4648 Hz
* Total bandwidth is about 6 Hz
* 50 bits of information are packaged into a 162 bit message with [FEC](https://en.wikipedia.org/wiki/Error_correction_code)
* Transmissions always begin 1 sec after even minutes (UTC)

### Resources
* [WSPR Code Generator](https://swharden.com/software/wspr-code-generator) - encode WSPR messages from your browser
* [WsprSharp](https://github.com/swharden/WsprSharp) - a .NET library for encoding and decoding WSPR transmissions using C#
* [FSKview](https://swharden.com/software/FSKview/) - spectrogram for viewing frequency-shift keyed (FSK) signals in real time
* [Anatomy of a WSPR transmission](https://swharden.com/software/FSKview/wspr/)
* [WSPR](https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software)) on Wikipedia
* [K1JT Program](http://physics.princeton.edu/pulsar/K1JT/devel.html)
* [Grid square lookup](http://www.levinecentral.com/ham/grid_square.php?Grid=FN20)
* [WSJT](https://sourceforge.net/projects/wsjt/) on SourceForge
* [WSPR Mode in WSJT-X](https://wsprnet.org/drupal/node/5563)
December 14th, 2020

Seven Years of QRSS Plus

This article was written for Andy (G0FTD) for publication in the December 2020 edition of 74!, The Knights QRSS Newsletter. Join the QRSS Knights mailing list for the latest QRSS news.

The QRSS hobby owes much of its success to the extraordinary efforts of amateur radio operators who run and maintain QRSS grabber stations. QRSS grabbers are built by pairing a radio receiver with a computer running software to continuously convert the received signals into spectrogram images which are uploaded to the internet every few minutes. QRSS Plus is a website that displays these spectrograms from active QRSS grabbers around the world. This article discusses the history of QRSS Plus, the technical details that make it possible, and highlights its most active contributors in 2020.

Early Days of QRSS Grabber Websites

In the early 2010s when I started to become active in the QRSS community, one of my favorite grabber websites was I2NDT's QRSS Knights Grabber Compendium. I remember checking that website from my laptop during class several times throughout the day to see if my signal was making it out of Gainesville, Florida. I also recall many nights at the bench tweaking my transmitter and looking at all the grabs from around the world trying to spot my signal.

A common problem with QRSS grabber websites was the persistance of outdated grabber images. Whenever a grabber uploaded a new spectrogram image it replaced the previous one, but when a grabber stopped uploading new images the old one would remain. Most uploaded spectrograms have a date written in small text in the corner, but at a glance (and especially in thumbnails) it was difficult to identify which grabber images were current and which were outdated.

History of QRSS Plus

I created QRSS Plus in July 2013 to solve the problem of outdated spectrograms appearing on grabber websites. QRSS Plus works by downloading grabber images every 10 minutes and recording their MD5 hash (a way to convert an image into a unique set of letters such that when the image changes the letters change). Grabbers were marked "active" if the MD5 hash from their newest image was different than the one from the previous image. This original system was entirely operated as a PHP script which ran on the back-end of a web server triggered by a cron job to download new images and update a database every 10 minutes. The primary weakness of this method was that downloading all those images took a lot of time (they were downloaded sequentially on the server). PHP is famously single-threaded, and my web host limited how long PHP scripts could run, limiting the maximum number of supported grabbers.

The back-end of QRSS Plus was redesigned in 2016 when I changed hosting companies. The new company allowed me to execute python scripts on the server, so I was no longer limited by the constraints of PHP. I redesigned QRSS Plus to download, hash, and store images every 10 minutes. This allowed QRSS Plus to display a running history of the last several grabs for each grabber, as well as support automated image stacking (averaging the last several images together to improve visualization of weak, repetitive signals). This solution is still limited by CPU time (the number of CPU seconds per day is capped by my hosting company), but continuously operating QRSS Plus does not occupy a large portion of that time.

QRSS Plus Activity in 2020

I started logging grabber updates in September 2018, allowing me to reflect on the last few years of grabber activity. It takes a lot of effort to set-up and maintain a quality QRSS grabber, and the enthusiasm and dedication of the QRSS community is impressive and inspiring!

In 2020 our community saw 155 active grabber stations! On average there were more than 60 active stations running on any given day, and the number of active stations is visibly increasing with time.

In 2020 QRSS Plus analyzed a mean of 6,041 spectrograms per day. In total, QRSS Plus analyzed over 2.2 million spectrograms this year!

This bar graph depicts the top 50 most active grabber stations ranked according to their total unique spectrogram upload count. Using this metric grabbers that update once every 10 minutes will appear to have twice as many unique grabber images as those which upload a unique image every 20 minutes.

Many QRSS grabber operators maintain multiple stations, and I think those operators deserve special attention! This year's winner for the most active contributor goes to David Hassall (WA5DJJ) who alone is responsible for 15.26% of the total number of uploaded spectrograms in 2020 🏆

The top 25 contributors with the greatest number of unique uploads in 2020 were (in order): WA5DJJ, WD4ELG, W6REK, G3VYZ, KL7L, G4IOG, W4HBK, G3YXM, HB9FXX, PA2OHH, EA8BVP, G0MQW, SA6BSS, WD4AH, 7L1RLL, VA3ROM, VE7IGH, DL4DTL, K5MO, LA5GOA, VE3GTC, AJ4VD, K4RCG, GM4SFW, and OK1FCX.

Maintaining QRSS Plus

I want to recognize Andy (G0FTD) for doing an extraordinary job maintaining the QRSS Plus website over the last several years! Although I (AJ4VD) created and maintain the QRSS Plus back-end, once it is set-up it largely operates itself. The QRSS grabber list, on the other hand, requires frequent curation. Andy has done a fantastic job monitoring the QRSS Knights mailing list and updating the grabber list in response to updates posted there so it always contains the newest grabbers and uses the latest URLs. On behalf of everyone who enjoys using QRSS Plus, thank you for your work Andy!

The Future of QRSS Plus

Today QRSS Plus is functional, but I think its front-end could be greatly improved. It is written using vanilla JavaScript, but I think moving to a front-end framework like React makes a lot of sense. Currently PHP generates HTML containing grabber data when the page is requested, but a public JSON API would make a lot of sense and make QRSS Plus it easier to develop and test. From a UX standpoint, the front-end could benefit from a simpler design that displays well on mobile and desktop browsers. I think the usability of historical grabs could be greatly improved as well. From a back-end perspective, I'd much prefer to run the application using a service like Azure or AWS rather than lean on a traditional personal website hosting plan to manage the downloads and image processing. Automatic creation of 8-hour (stitched and compressed) grabber frames seems feasible as well. It is unlikely I will work toward these improvements soon, but if you are a front-end web developer interested in working on a public open-source project, send me an email and I'd be happy to discuss how we can improve QRSS Plus together!

QRSS is a growing hobby, and if the rise in grabbers over the last few years is an indication of what the next few years will look like, I'm excited to see where the hobby continues to go! I encourage you to consider running a grabber (and to encourage others to do the same), and to continue to thank all the grabber operators and maintainers out there who make this hobby possible.

Notes and Resources

  • Data includes Jan 1 2020 through Dec 11 2020
  • Stations with <1000 unique uploads were excluded from most analyses
  • Summary data (a table of unique images per day per station) is available: qrss-plus-2020.xlsx
  • Bar graphs, scatter plots, and line charts were created with ScottPlot
  • QRSS Plus is open source on GitHub
  • A modern introduction to QRSS: The New Age of QRSS
  • FSKview is a new QRSS and WSPR Spectrogram Viewer for Windows
Markdown source code last modified on January 18th, 2021
---
title: Seven Years of QRSS Plus
date: 2020-12-14 21:16:00
tags: qrss, amateur radio
---

# Seven Years of QRSS Plus

> This article was written for [Andy (G0FTD)](https://sites.google.com/view/andy-g0ftd/) for publication in the December 2020 edition of [74!, The Knights QRSS Newsletter](https://swharden.com/qrss/74/). Join the [QRSS Knights mailing list](https://groups.io/g/qrssknights) for the latest QRSS news.

The QRSS hobby owes much of its success to the extraordinary efforts of amateur radio operators who run and maintain QRSS grabber stations. QRSS grabbers are built by pairing a radio receiver with a computer running software to continuously convert the received signals into spectrogram images which are uploaded to the internet every few minutes. [**QRSS Plus**](https://swharden.com/qrss/plus/) is a website that displays these spectrograms from active QRSS grabbers around the world. This article discusses the history of QRSS Plus, the technical details that make it possible, and highlights its most active contributors in 2020.

### Early Days of QRSS Grabber Websites

In the early 2010s when I started to become active in the QRSS community, one of my favorite grabber websites was [I2NDT's QRSS Knights Grabber Compendium](https://digilander.libero.it/i2ndt/grabber/grabber-compendium.htm). I remember checking that website from my laptop during class several times throughout the day to see if my signal was making it out of Gainesville, Florida. I also recall many nights at the bench tweaking my transmitter and looking at all the grabs from around the world trying to spot my signal. 

A common problem with QRSS grabber websites was the persistance of outdated grabber images. Whenever a grabber uploaded a new spectrogram image it replaced the previous one, but when a grabber stopped uploading new images the old one would remain. Most uploaded spectrograms have a date written in small text in the corner, but at a glance (and especially in thumbnails) it was difficult to identify which grabber images were current and which were outdated. 

### History of QRSS Plus

I created [QRSS Plus](https://swharden.com/qrss/plus/) in July 2013 to solve the problem of outdated spectrograms appearing on grabber websites. QRSS Plus works by downloading grabber images every 10 minutes and recording their [MD5 hash](https://en.wikipedia.org/wiki/MD5) (a way to convert an image into a unique set of letters such that when the image changes the letters change). Grabbers were marked "active" if the MD5 hash from their newest image was different than the one from the previous image. This original system was entirely operated as a PHP script which ran on the back-end of a web server triggered by a cron job to download new images and update a database every 10 minutes. The primary weakness of this method was that downloading all those images took a lot of time (they were downloaded sequentially on the server). PHP is famously single-threaded, and my web host limited how long PHP scripts could run, limiting the maximum number of supported grabbers.

The back-end of QRSS Plus was redesigned in 2016 when I changed hosting companies. The new company allowed me to execute python scripts on the server, so I was no longer limited by the constraints of PHP. I redesigned QRSS Plus to download, hash, and store images every 10 minutes. This allowed QRSS Plus to display a running history of the last several grabs for each grabber, as well as support automated image stacking (averaging the last several images together to improve visualization of weak, repetitive signals). This solution is still limited by CPU time (the number of CPU seconds per day is capped by my hosting company), but continuously operating QRSS Plus does not occupy a large portion of that time.

### QRSS Plus Activity in 2020

I started logging grabber updates in September 2018, allowing me to reflect on the last few years of grabber activity. It takes a lot of effort to set-up and maintain a quality QRSS grabber, and the enthusiasm and dedication of the QRSS community is impressive and inspiring! 

<div class="text-center">

![](grabbers-per-day.png)

</div>

In 2020 our community saw ***155 active grabber stations***! On average there were more than 60 active stations running on any given day, and the number of active stations is visibly increasing with time.

<div class="text-center">

![](grabs-per-day.png)

</div>

In 2020 QRSS Plus analyzed a mean of 6,041 spectrograms per day. In total, QRSS Plus analyzed over ***2.2 million spectrograms*** this year!

<div class="text-center">

![](grabbers-leader.png)

</div>

This bar graph depicts the top 50 most active grabber stations ranked according to their total unique spectrogram upload count. Using this metric grabbers that update once every 10 minutes will appear to have twice as many unique grabber images as those which upload a unique image every 20 minutes.

<div class="text-center">

![](qrss-2020-pie.png)

</div>

Many QRSS grabber operators maintain multiple stations, and I think those operators deserve special attention! This year's winner for the most active contributor goes to David Hassall (WA5DJJ) who alone is responsible for 15.26% of the total number of uploaded spectrograms in 2020 🏆

The top 25 contributors with the greatest number of unique uploads in 2020 were (in order): WA5DJJ, WD4ELG, W6REK, G3VYZ, KL7L, G4IOG, W4HBK, G3YXM, HB9FXX, PA2OHH, EA8BVP, G0MQW, SA6BSS, WD4AH, 7L1RLL, VA3ROM, VE7IGH, DL4DTL, K5MO, LA5GOA, VE3GTC, AJ4VD, K4RCG, GM4SFW, and OK1FCX. 

### Maintaining QRSS Plus

I want to recognize Andy (G0FTD) for doing an extraordinary job maintaining the QRSS Plus website over the last several years! Although I (AJ4VD) created and maintain the QRSS Plus back-end, once it is set-up it largely operates itself. The QRSS grabber list, on the other hand, requires frequent curation. Andy has done a fantastic job monitoring the [QRSS Knights mailing list](https://groups.io/g/qrssknights) and updating the grabber list in response to updates posted there so it always contains the newest grabbers and uses the latest URLs. On behalf of everyone who enjoys using QRSS Plus, thank you for your work Andy!

### The Future of QRSS Plus

Today QRSS Plus is functional, but I think its front-end could be greatly improved. It is written using vanilla JavaScript, but I think moving to a front-end framework like React makes a lot of sense. Currently PHP generates HTML containing grabber data when the page is requested, but a public JSON API would make a lot of sense and make QRSS Plus it easier to develop and test. From a UX standpoint, the front-end could benefit from a simpler design that displays well on mobile and desktop browsers. I think the usability of historical grabs could be greatly improved as well. From a back-end perspective, I'd much prefer to run the application using a service like Azure or AWS rather than lean on a traditional personal website hosting plan to manage the downloads and image processing. Automatic creation of 8-hour (stitched and compressed) grabber frames seems feasible as well. It is unlikely I will work toward these improvements soon, but if you are a front-end web developer interested in working on a public open-source project, send me an email and I'd be happy to discuss how we can improve QRSS Plus together!

QRSS is a growing hobby, and if the rise in grabbers over the last few years is an indication of what the next few years will look like, I'm excited to see where the hobby continues to go! I encourage you to consider running a grabber (and to encourage others to do the same), and to continue to thank all the grabber operators and maintainers out there who make this hobby possible.

### Notes and Resources
* Data includes Jan 1 2020 through Dec 11 2020
* Stations with <1000 unique uploads were excluded from most analyses
* Summary data (a table of unique images per day per station) is available: [qrss-plus-2020.xlsx](qrss-plus-2020.xlsx)
* Bar graphs, scatter plots, and line charts were created with [ScottPlot](https://swharden.com/scottplot)
* QRSS Plus is [open source on GitHub](https://github.com/swharden/qrssplus)
* A modern introduction to QRSS: [The New Age of QRSS](https://swharden.com/blog/2020-10-03-new-age-of-qrss)
* [FSKview](https://swharden.com/software/FSKview) is a new QRSS and WSPR Spectrogram Viewer for Windows
October 3rd, 2020

The New Age of QRSS

QRSS is an experimental radio mode that uses frequency-shift-keyed (FSK) continuous wave (CW) Morse code to transmit messages that can be decoded visually by inspecting the radio frequency spectrogram. The name "QRSS" is a derivation of the Q code "QRS", a phrase Morse code operators send to indicate the transmitter needs to slow down. The extra "S" means slow way, way down, and at the typical speed of 6 second dots and 18 second dashes most QRSS operators have just enough time to send their call sign once every ten minutes (as required by federal law). These slow Morse code messages can be decoded by visual inspection of spectrograms created by computer software processing the received audio. A QRSS grabber is a radio/computer setup configured to upload the latest radio spectrogram to the internet every 10 minutes. QRSS Plus is an automatically-updating list of active QRSS grabbers around the world, allowing the QRSS community to see QRSS transmitters being detected all over the world.

TLDR: Get Started with QRSS

  • Tune your radio to 10.140 MHz (10.1387 MHz USB)
  • Install spectrogram software like FSKview
  • Inspect the spectrogram to decode callsigns visually
  • Join the QRSS Knights mailing list to learn what's new
  • Go to QRSS Plus to see QRSS signals around the world
  • Design and build a circuit (or buy a kit) to transmit QRSS

What is QRSS?

QRSS allows miniscule amounts of power to send messages enormous distances. For example, 200 mW QRSS transmitters are routinely spotted on QRSS grabbers thousands of miles away. The key to this resilience lies in the fact that spectrograms can be designed which average several seconds of audio into each pixel. By averaging audio in this way, the level of the noise (which is random and averages toward zero) falls below the level of the signal, allowing visualization of signals on the spectrogram which are too deep in the noise to be heard by ear.

If you have a radio and a computer, you can view QRSS! Connect your radio to your computer's microphone, then run a spectrogram like FSKview to visualize that audio as a spectrogram. The most QRSS activity is on 30m within 100 Hz of 10.140 MHz, so set your radio to upper sideband (USB) mode and tune to 10.1387 MHz so QRSS audio will be captured as 1.4 kHz audio tones.

FSKview is radio frequency spectrogram software for viewing QRSS and WSPR simultaneously. I wrote FSKview to be simple and easy to use, but it's worth noting that Spectrum Lab, Argo, LOPORA, and QRSSpig are also popular spectrogram software projects used for QRSS, with the last two supporting Linux and suitable for use on the Raspberry Pi.

QRSS Transmitter Design

QRSS transmitters can be extraordinarily simple because they just transmit a single tone which shifts between two frequencies. The simplicity of QRSS transmitters makes them easy to assemble as a kits, or inexpensively designed and built by those first learning about RF circuit design. The simplest designs use a crystal oscillator (typically a Colpitts configuration) followed by a buffer stage and a final amplifier (often Class C configuration using a 2N7000 N-channel MOSFET or 2N2222 NPN transistor). Manual frequency adjustments are achieved using a variable capacitor, supplemented in this case with twisted wire to act as a simple but effective variable capacitor for fine frequency tuning within the 100 Hz QRSS band. Frequency shift keying to transmit call signs is typically achieved using a microcontroller to adjust voltage on a reverse-biased diode (acting as a varactor) to modulate capacitance and shift resonant frequency of the oscillator. Following a low-pass filter (typically a 3-pole Chebyshev design) the signal is then sent to an antenna.

QRP Labs is a great source for QRSS kits. The kit pictured above and below is one of their earliest kits (the 30/40/80/160m QRSS Kit), but they have created many impressive new products in the last several years. Some of their more advanced QRSS kits leverage things like direct digital synthesis (DDS), GPS time synchronization, and the ability to transmit additional digital modes like Hellschreiber and WSPR.

Radio Frequency Spectral Phenomena

Atmospheric phenomena and other special conditions can often be spotted in QRSS spectrograms. One of the most common special cases are radio frequency reflections off of airplanes resulting in the radio waves arriving at the receiver simultaneously via two different paths (a form of multipath propagation). Due to the Doppler shift from the airplane approaching the receiver the signal from the reflected path appears higher frequency than the direct path, and as the airplane flies over and begins heading away the signal from the reflected path decreases in frequency relative to the signal of the direct path. The image below is one of my favorites, captured by Andy (G0FTD) in the 10m QRSS band. QRSS de W4HBK is a website that has many blog posts about rare and special grabs, demonstrating effects of meteors and coronal mass ejections on QRSS signals.

QRSS Transmitters are Not Beacons

Radio beacons send continuous, automated, unattended, one-way transmissions without specific reception targets. In contrast, QRSS transmitters are only intended to be transmitting when the control operator is available to control them, and the recipients are known QRSS grabbers around the world. To highlight the distinction from radio beacons, QRSS transmitters are termed Manned Experimental Propagation Transmitters (MEPTs). Users in the United States will recall that the FCC (in Part 97.203) confines operation of radio beacons to specific regions of the radio spectrum and disallows operation of beacons below 28 MHz. Note that amateur radio beacons typically operate up to 100 W which is a power level multiple orders of magnitude greater than QRSS transmitters. MEPTs, in contrast, can transmit in any portion of the radio frequency spectrum where CW operation is permitted.

The New Age of QRSS

QRSS was first mentioned in epsisode 28 of The Soldersmoke Podcast on July 30, 2006. It was discussed in several episodes over the next few years, and a 2009 post about QRSS on Hack-A-Day brought it to my attention. In the early days of QRSS the only way to transmit QRSS was to design and build your own transmitter. David Hassall (WA5DJJ), Bill Houghton (W4HBK), Hans Summers (G0UPL), and others would post their designs on their personal websites along with notes about where their transmitters had been spotted. In the following years the act of creating QRSS grabbers became streamlined, and websites like I2NDT's QRSS Grabber Compendium and QRSS Plus made it easier to see QRSS signals around the world. Hans Summers (G0UPL) began selling QRSS transmitter kits at amateur radio conventions, then later through the QRP Labs website. As more people started selling and buying kits (and documenting their experiences) it became easier and easier to get started with QRSS. Before QRSS kits were easy to obtain the only way to participate in the hobby was to design and build a transmitter from scratch, representing a high barrier to entry for those potentially interested in this fascinating hobby. Now with the availability of high quality QRSS transmitter kits and the ubiquity of internet tools and software to facilitate QRSS reception, it's easier than ever to get involved in this exciting field! For these reasons I believe we have entered into a New Age of QRSS.

QRSS Frequency Bands

This table shows the QRSS frequency range for every major amateur radio band. Primary QRSS band windows are 100-200 Hz wide and located just below the WSPR bands (so WSPR transmissions frequently appear on QRSS grabs). Experimentation is encouraged on the lower portion of the band and the upper portion is typically used for mature and stable transmitters.

Band QRSS Frequency (±100 Hz) Dial Frequency (Hz)
600m 476,100 474,200
160m 1,837,900 1,836,600
80m 3,569,900 ⭐ popular 3,568,600
60m 5,288,550 5,287,200
40m 7,039,900 ⭐ popular 7,038,600
30m 10,140,000 🌟 most popular 10,138,700
20m 14,096,900 ⭐ popular 14,095,600
17m 18,105,900 18,104,600
15m 21,095,900 21,094,600
12m 24,925,900 24,924,600
10m 28,125,700 (±200 Hz) 28,124,600
6m 50,294,300 50,293,000

⚠️ WARNING: It may not be legal for you to transmit on these frequencies. Check license requirements and regulations for your region before transmitting QRSS.

⚠️ WARNING: These frequencies sometimes change based upon community discussion. Frequency tables can be found on the Knights QRSS Wiki. Outdated or alternate frequencies include 160m (1,843,200 Hz), 80m (3,593,900 Hz), 12m (24,890,800 Hz), 10m (28,000,800 Hz and 28,322,000 ±500 Hz), and 6m (50,000,900 Hz). Experimentation on 10m is encouraged in the 100Hz above the band.

When tuning your radio your dial frequency may be lower than the QRSS frequency. If you are using upper-sideband (USB) mode, you have to tune your radio dial 1.4 kHz below the QRSS band to hear QRSS signals as a 1.4 kHz tone. Recommended dial frequencies in the table above are suitable for receiving QRSS and WSPR.

QRSS Knights

The QRSS Knights is a group of QRSS enthusiasts who coordinate events and discuss experiments over email. The group is kind and welcoming to newcomers, and those interested in learning more about QRSS are encouraged to join the mailing list.

Resources

  • This page can be found at http://swharden.com/qrss

  • QRSS Plus is an automatically-updating active QRSS grabber list

  • What is QRSS by M0AYF is a classic summary of QRSS, with many links to detailed schematics and design consideration notes. Notably the sections for receiving QRSS and transmitting QRSS are great places to learn more.

  • QRSS and You by KA7OEI is another classic summary of QRSS.

  • Weak Signal Propagation Reporter (WSPR) is a low power radio protocol that typically operates adjacent to the QRSS bands and provides automated decoding of callsign, power, and location information. Read more at http://wsprnet.org

  • The QRSS Adventure by Dave Hassall (WA5DJJ) has circuit designs and commentary spanning far back into the early days of QRSS. His 1,164,000,000 Miles per Watt Test is extraordinary!

  • QRSS de W4HBK website by Bill Houghton (W4HBK) contains many useful blog posts about advanced QRSS topics. The website also has many examples of special grabs depicting rare events and atmospheric phenomena.

  • Hans Summers' website (the founder of QRP Labs) has many excellent resources related to RF design and early work in the QRSS space.

  • Simple QRP Equipment by Onno (PA2OHH) is a collection of fantastic resources related to QRSS transmission, reception, and software design.

  • Electronics & HAM Radio Blog by Eldon Brown (WA0UWH) has many fantastic articles about QRSS. Eldon's SMT band-edge transmitter inspired me to make a SMT QRSS transmitter many years later.

  • Dave Richards, AA7EE has a fantastic website documenting many amateur radio topics including QRSS. This website has the prettiest pictures of circuit boards you'll ever see.

  • Andy, G0FTD has an excellent website with many pages about radio transmitters and QRSS including a gallery of interesting QRSS grabs

  • My QRSS Hardware GitHub page collects notes and resources related to QRSS transmitter and receiver design.

Markdown source code last modified on January 18th, 2021
---
title: The New Age of QRSS
date: 2020-10-03 22:08:00
tags: qrss, amateur radio
---

# The New Age of QRSS

**QRSS is an experimental radio mode that uses frequency-shift-keyed (FSK) continuous wave (CW) Morse code to transmit messages that can be decoded visually by inspecting the radio frequency spectrogram.** The name "QRSS" is a derivation of the [Q code](https://en.wikipedia.org/wiki/Q_code) "QRS", a phrase Morse code operators send to indicate the transmitter needs to slow down. The extra "S" means slow way, _way_ down, and at the typical speed of 6 second dots and 18 second dashes most QRSS operators have just enough time to send their call sign once every ten minutes (as required by federal law). These slow Morse code messages can be decoded by visual inspection of spectrograms created by computer software processing the received audio. A QRSS grabber is a radio/computer setup configured to upload the latest radio spectrogram to the internet every 10 minutes. [QRSS Plus](https://swharden.com/qrss/plus/) is an automatically-updating list of active QRSS grabbers around the world, allowing the QRSS community to see QRSS transmitters being detected all over the world. 

> **TLDR: Get Started with QRSS**
> * Tune your radio to 10.140 MHz (10.1387 MHz USB)
> * Install spectrogram software like [FSKview](https://swharden.com/software/FSKview)
> * Inspect the spectrogram to decode callsigns visually
> * Join the [QRSS Knights](https://groups.io/g/qrssknights) mailing list to learn what's new
> * Go to [QRSS Plus](https://swharden.com/qrss/plus/) to see QRSS signals around the world
> * Design and build a circuit (or [buy a kit](https://www.qrp-labs.com/)) to transmit QRSS

## What is QRSS?

**QRSS allows miniscule amounts of power to send messages enormous distances.** For example, 200 mW QRSS transmitters are routinely spotted on QRSS grabbers thousands of miles away. The key to this resilience lies in the fact that spectrograms can be designed which average several seconds of audio into each pixel. By averaging audio in this way, the level of the noise (which is random and averages toward zero) falls below the level of the signal, allowing visualization of signals on the spectrogram which are too deep in the noise to be heard by ear.

<div class="text-center img-border">

![](lopora-signals2.jpg)

</div>

**If you have a radio and a computer, you can view QRSS!** Connect your radio to your computer's microphone, then run a spectrogram like [FSKview](https://swharden.com/software/FSKview/) to visualize that audio as a spectrogram. The most QRSS activity is on 30m within 100 Hz of 10.140 MHz, so set your radio to upper sideband (USB) mode and tune to 10.1387 MHz so QRSS audio will be captured as 1.4 kHz audio tones. 

**[FSKview](https://swharden.com/software/FSKview/) is radio frequency spectrogram software for viewing QRSS and WSPR simultaneously.** I wrote [FSKview](https://swharden.com/software/FSKview/) to be simple and easy to use, but it's worth noting that [Spectrum Lab](https://www.qsl.net/dl4yhf/spectra1.html),  [Argo](https://digilander.libero.it/i2phd/argo/), [LOPORA](https://www.qsl.net/pa2ohh/11lop.htm), and [QRSSpig](https://gitlab.com/hb9fxx/qrsspig) are also popular spectrogram software projects used for QRSS, with the last two supporting Linux and suitable for use on the Raspberry Pi.

<div class="text-center">

![](fskview.png)

</div>

## QRSS Transmitter Design

**QRSS transmitters can be extraordinarily simple because they just transmit a single tone which shifts between two frequencies.** The simplicity of QRSS transmitters makes them easy to assemble as a kits, or inexpensively designed and built by those first learning about RF circuit design. The simplest designs use a crystal oscillator (typically a [Colpitts](https://en.wikipedia.org/wiki/Colpitts_oscillator) configuration) followed by a buffer stage and a final amplifier (often [Class C](https://en.wikipedia.org/wiki/Power_amplifier_classes#Class_C) configuration using a 2N7000 N-channel MOSFET or 2N2222 NPN transistor). Manual frequency adjustments are achieved using a variable capacitor, supplemented in this case with twisted wire to act as a simple but effective variable capacitor for fine frequency tuning within the 100 Hz QRSS band. Frequency shift keying to transmit call signs is typically achieved using a microcontroller to adjust voltage on a reverse-biased diode (acting as a [varactor](https://en.wikipedia.org/wiki/Varicap)) to modulate capacitance and shift resonant frequency of the oscillator. Following a low-pass filter (typically a 3-pole [Chebyshev](https://en.wikipedia.org/wiki/Chebyshev_filter) design) the signal is then sent to an antenna.

<div class="text-center img-medium">

![](qrp-labs-kit-schematic.jpg)

</div>

**[QRP Labs](https://www.qrp-labs.com/) is a great source for QRSS kits.** The kit pictured above and below is one of their earliest kits (the 30/40/80/160m QRSS Kit), but they have created many impressive new products in the last several years. Some of their more advanced QRSS kits leverage things like direct digital synthesis (DDS), GPS time synchronization, and the ability to transmit additional digital modes like Hellschreiber and WSPR.

<div class="text-center img-border img-medium">

![](qrp-labs-kit-photo.jpg)

</div>

## Radio Frequency Spectral Phenomena

**Atmospheric phenomena and other special conditions can often be spotted in QRSS spectrograms**. One of the most common special cases are radio frequency reflections off of airplanes resulting in the radio waves arriving at the receiver simultaneously via two different paths (a form of [multipath propagation](https://en.wikipedia.org/wiki/Multipath_propagation)). Due to the Doppler shift from the airplane approaching the receiver the signal from the reflected path appears higher frequency than the direct path, and as the airplane flies over and begins heading away the signal from the reflected path decreases in frequency relative to the signal of the direct path. The image below is one of my favorites, captured by [Andy (G0FTD)](https://sites.google.com/view/andy-g0ftd/the-qrss-gallery) in the 10m QRSS band. [QRSS de W4HBK](http://pensacolasnapper.blogspot.com/) is a website that has many blog posts about rare and special grabs, demonstrating effects of meteors and coronal mass ejections on QRSS signals.

<div class="text-center img-medium">

![](rf-reflection-airplane.png)

</div>

<div class="text-center img-medium img-border">

![](rf-reflection-airplane.jpg)

</div>

## QRSS Transmitters are Not Beacons

Radio beacons send continuous, automated, unattended, one-way transmissions without specific reception targets. In contrast, QRSS transmitters are only intended to be transmitting when the control operator is available to control them, and the recipients are known QRSS grabbers around the world. To highlight the distinction from radio beacons, QRSS transmitters are termed ***Manned Experimental Propagation Transmitters (MEPTs)***. Users in the United States will recall that the FCC (in Part 97.203) confines operation of radio beacons to specific regions of the radio spectrum and disallows operation of beacons below 28 MHz. Note that amateur radio beacons typically operate up to 100 W which is a power level multiple orders of magnitude greater than QRSS transmitters. MEPTs, in contrast, can transmit in any portion of the radio frequency spectrum where CW operation is permitted.

## The New Age of QRSS
**QRSS was first mentioned in epsisode 28 of [The Soldersmoke Podcast](http://www.soldersmoke.com/) on July 30, 2006.** It was discussed in several episodes over the next few years, and a 2009 [post about QRSS](https://hackaday.com/2009/02/22/qrss-radio-amateurs-slow-speed-narrowband/) on Hack-A-Day brought it to my attention. In the early days of QRSS the only way to transmit QRSS was to design and build your own transmitter. [David Hassall (WA5DJJ)](http://www.zianet.com/dhassall/QRSS_A.html), [Bill Houghton (W4HBK)](http://pensacolasnapper.blogspot.com/), [Hans Summers (G0UPL)](http://www.hanssummers.com/), and others would post their designs on their personal websites along with notes about where their transmitters had been spotted. In the following years the act of creating QRSS grabbers became streamlined, and websites like I2NDT's [QRSS Grabber Compendium](https://digilander.libero.it/i2ndt/grabber/grabber-compendium.htm) and [QRSS Plus](https://swharden.com/qrss/plus/) made it easier to see QRSS signals around the world. [Hans Summers](http://www.hanssummers.com/) (G0UPL) began selling QRSS transmitter kits at amateur radio conventions, then later through the [QRP Labs website](https://www.qrp-labs.com/). As more people started selling and buying kits (and documenting their experiences) it became easier and easier to get started with QRSS. Before QRSS kits were easy to obtain the only way to participate in the hobby was to design and build a transmitter from scratch, representing a high barrier to entry for those potentially interested in this fascinating hobby. Now with the availability of high quality QRSS transmitter kits and the ubiquity of internet tools and software to facilitate QRSS reception, it's easier than ever to get involved in this exciting field! For these reasons I believe we have entered into a _New Age of QRSS_.

## QRSS Frequency Bands

**This table shows the QRSS frequency range for every major amateur radio band.** Primary QRSS band windows are 100-200 Hz wide and located just below the [WSPR](http://wsprnet.org/) bands (so WSPR transmissions frequently appear on QRSS grabs). Experimentation is encouraged on the lower portion of the band and the upper portion is typically used for mature and stable transmitters.

<div class="text-center">

Band | QRSS Frequency (±100 Hz)     | Dial Frequency (Hz)
-----|------------------------------|-----------------------
600m | 476,100						| 474,200
160m | 1,837,900					| 1,836,600
80m  | 3,569,900 ⭐ _popular_		| 3,568,600
60m  | 5,288,550					| 5,287,200
40m  | 7,039,900 ⭐ _popular_		| 7,038,600
30m  | 10,140,000 🌟 _most popular_	| 10,138,700
20m  | 14,096,900 ⭐ _popular_		| 14,095,600
17m  | 18,105,900					| 18,104,600
15m  | 21,095,900					| 21,094,600
12m  | 24,925,900					| 24,924,600
10m  | 28,125,700 (±200 Hz)			| 28,124,600
6m   | 50,294,300					| 50,293,000

</div>

> **⚠️ WARNING:** It may not be legal for you to transmit on these frequencies. Check license requirements and regulations for your region before transmitting QRSS.

> **⚠️ WARNING:** These frequencies sometimes change based upon community discussion. Frequency tables can be found on the [Knights QRSS Wiki](https://groups.io/g/qrssknights/wiki/3964). Outdated or alternate frequencies include 160m (1,843,200 Hz), 80m (3,593,900 Hz), 12m (24,890,800 Hz), 10m (28,000,800 Hz and 28,322,000 ±500 Hz), and 6m (50,000,900 Hz). Experimentation on 10m is encouraged in the 100Hz above the band.

**When tuning your radio your dial frequency may be lower than the QRSS frequency.** If you are using upper-sideband (USB) mode, you have to tune your radio dial 1.4 kHz _below_ the QRSS band to hear QRSS signals as a 1.4 kHz tone. Recommended dial frequencies in the table above are suitable for receiving QRSS and WSPR.

## QRSS Knights

**The [QRSS Knights](https://groups.io/g/qrssknights) is a group of QRSS enthusiasts** who coordinate events and discuss experiments over email. The group is kind and welcoming to newcomers, and those interested in learning more about QRSS are encouraged to join the mailing list.

## Resources

* This page can be found at http://swharden.com/qrss

* [QRSS Plus](https://swharden.com/qrss/plus/) is an automatically-updating active QRSS grabber list

* [What is QRSS](https://www.qsl.net/m0ayf/What-is-QRSS.html) by M0AYF is a classic summary of QRSS, with many links to detailed schematics and design consideration notes. Notably the sections for [receiving QRSS](https://www.qsl.net/m0ayf/Receiving-QRSS.html) and [transmitting QRSS](https://www.qsl.net/m0ayf/Transmitting-QRSS.html) are great places to learn more.

* [QRSS and You](http://www.ka7oei.com/qrss1.html) by KA7OEI is another classic summary of QRSS.

* Weak Signal Propagation Reporter (WSPR) is a low power radio protocol that typically operates adjacent to the QRSS bands and provides automated decoding of callsign, power, and location information. Read more at http://wsprnet.org

* [The QRSS Adventure](http://www.zianet.com/dhassall/QRSS_A.html) by Dave Hassall (WA5DJJ) has circuit designs and commentary spanning far back into the early days of QRSS. His [ 1,164,000,000 Miles per Watt Test](http://www.zianet.com/dhassall/BILLIONMPW.html) is extraordinary!

* [QRSS de W4HBK](http://pensacolasnapper.blogspot.com/) website by Bill Houghton (W4HBK) contains many useful blog posts about advanced QRSS topics. The website also has many examples of special grabs depicting rare events and atmospheric phenomena.

* [Hans Summers' website](http://www.hanssummers.com/) (the founder of [QRP Labs](https://www.qrp-labs.com/)) has many excellent resources related to RF design and early work in the QRSS space.

* [Simple QRP Equipment](https://www.qsl.net/pa2ohh/) by Onno  (PA2OHH) is a collection of fantastic resources related to QRSS transmission, reception, and software design.

* [Electronics & HAM Radio Blog](http://wa0uwh.blogspot.com/) by Eldon Brown (WA0UWH) has many fantastic articles about QRSS. Eldon's SMT band-edge transmitter inspired me to make a SMT QRSS transmitter many years later.

* [Dave Richards, AA7EE](https://aa7ee.wordpress.com/) has a fantastic website documenting many amateur radio topics including QRSS. This website has the prettiest pictures of circuit boards you'll ever see.

* [Andy, G0FTD](https://sites.google.com/view/andy-g0ftd/home) has an excellent website with many pages about radio transmitters and QRSS including a [gallery of interesting QRSS grabs](https://sites.google.com/view/andy-g0ftd/the-qrss-gallery)

* My [QRSS Hardware](https://github.com/swharden/QRSS-hardware) GitHub page collects notes and resources related to QRSS transmitter and receiver design.

<div class="text-center img-border">

![](smt-qrss.jpg)

</div>
July 31st, 2019

Upgraded Amplifier

The design is similar (CMOS buffer driving an IRF510) but I used perfboard to make this one and placed it in an enclosure. There's no low-pass filter on the amplifier itself, but I put a 30m low-pass filter in-line the coax before the antenna. It's currently outputting 20PPV into 50 ohms (1 watt).

Old Amplifier

New Amplifier

Right after hooking it up I saw my signal looking nice on the air:

AJ4VD Spotted in Ontario, Canada (VA3ROM)

AJ4VD Spotted in the Canary Islands (EA8BVP1)

Markdown source code last modified on January 18th, 2021
---
title: Upgraded Amplifier
date: 2019-07-31 21:00:00
tags: qrss, circuit
---

# Upgraded Amplifier

The design is similar (CMOS buffer driving an IRF510) but I used perfboard to make this one and placed it in an enclosure. There's no low-pass filter on the amplifier itself, but I put a 30m low-pass filter in-line the coax before the antenna. It's currently outputting 20PPV into 50 ohms (1 watt).

### Old Amplifier

<div class="text-center img-border">

[![](2019-07-30-old-amp_thumb.jpg)](2019-07-30-old-amp.jpg)

</div>

### New Amplifier

<div class="text-center">

[![](schematic_thumb.jpg)](schematic.png)

</div>

<div class="text-center img-border">

[![](2019-07-31-new-amp_thumb.jpg)](2019-07-31-new-amp.jpg)

</div>

Right after hooking it up I saw my signal looking nice on the air:

### AJ4VD Spotted in Ontario, Canada (VA3ROM)

<div class="text-center img-border">

[![](VA3ROM.1907311950.549006f9e5_thumb.jpg)](VA3ROM.1907311950.549006f9e5.jpg)

</div>

### AJ4VD Spotted in the Canary Islands (EA8BVP1)

<div class="text-center img-border">

[![](EA8BVP1.1907311940.821b800321_thumb.jpg)](EA8BVP1.1907311940.821b800321.jpg)

</div>
July 29th, 2019

SMT QRSS Spots

This page documents interesting grabs of the signal from my SMT QRSS Transmitter

2019-07-29

Nova Scotia, Canada (VE1VDM)

I was really strong on VE1VDM's grabber last night, but I found it interesting to see such a strong signal in the middle of the day (11AM).

Stack (average of 13 grabs)

2019-07-30

I spotted my signal across the Atlantic. It's pretty weak, but you can just make out the unique shape on EA8BVP's grabber in the Canary Islands (4,000 miles away).

2019-08-03

I spotted my signal in Sweden. This hint of my transmitter was captured by SA6BSS in Slutarp, Sweden at 12:30AM last night.

2019-09-02

I spotted my signal in Switzerland

Bill (W4HBK) emailed the QRSS Knights a grab of my signal from a KIWI SDR captured at HB9EHO in Ittigen, Switzerland.

Markdown source code last modified on January 18th, 2021
---
title: SMT QRSS Spots
date: 2019-07-29 21:00:00
tags: qrss
---

# SMT QRSS Spots

This page documents interesting grabs of the signal from my [SMT QRSS Transmitter](https://swharden.com/blog/2019-07-26-smt-qrss-design/)

## 2019-07-29

### Nova Scotia, Canada (VE1VDM)

I was really strong on VE1VDM's grabber last night, but I found it interesting to see such a strong signal in the middle of the day (11AM).

<div class="text-center img-border">

[![](VE1VDM.1907290830.35415d51dc_thumb.jpg)](VE1VDM.1907290830.35415d51dc.jpg)

</div>

### Stack (average of 13 grabs)

<div class="text-center img-border">

[![](VE1VDM.1907290940_thumb.jpg)](VE1VDM.1907290940.jpg)

</div>

## 2019-07-30

I spotted my signal across the Atlantic. It's pretty weak, but you can just make out the unique shape on EA8BVP's grabber in the Canary Islands (4,000 miles away).

<div class="text-center img-border">

[![](EA8BVP1.1907302050_thumb.jpg)](EA8BVP1.1907302050.jpg)

</div>

## 2019-08-03

I spotted my signal in Sweden. This hint of my transmitter was captured by SA6BSS in Slutarp, Sweden at 12:30AM last night.

<div class="text-center img-border">

[![](SA6BSS-AJ4VD_thumb.jpg)](SA6BSS-AJ4VD.jpg)

</div>

<div class="text-center img-border img-medium">

[![](globe_thumb.jpg)](globe.png)

</div>

## 2019-09-02

I spotted my signal in Switzerland

[Bill (W4HBK)](https://www.qsl.net/w4hbk/) emailed the [QRSS Knights](https://groups.io/g/qrssknights) a grab of my signal from a KIWI SDR captured at HB9EHO in Ittigen, Switzerland.

<div class="text-center img-border">

[![](HB9EHO_thumb.jpg)](HB9EHO.jpg)

</div>
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