ARRL Frequency Measuring Test for April 2020: The results are in!

The spring Frequency Measuring Test was 0200Z-0225Z on Apr 24! (For those of us in the United States, that means the evening of the 23rd.)  The radio club did well with at least five entries, two of which are in the winners’ circle as seen below.

From the ARRL web site:


The results of the spring 2020 ARRL Frequency Measuring Test (FMT), conducted on April 24, have been posted. Coming in at the top of the list for stations entering readings of both the 40-meter and 80-meter frequencies was Steve Cerwin, WA5FRF. His average error rate was 0.004902 parts per million (ppm).The Top 10 looked like this, with average error rates in ppm. Bill De Carle, VE2IQ, has posted a ranked list of participants who submitted readings for both frequencies.

















N8OBJ, John Gibbons






KB3UMD, Aidan Montare








Today’s FMTs are conducted completely online, with no manual log-checking or intervention. Connie Marshall, K5CM, provides Bruce Horn, WA7BNM, with the precise actual frequencies, participating individuals submit their measurements, and machines handle the rest. Ninety-eight radio amateurs took part on the April 2020 FMT. The next FMT will take place in November.

Taking part in the FMT does not require special laboratory equipment. Modern HF transceivers can measure frequency quite accurately, and SDR-based receivers and available software can enable precise frequency measurements. Today’s FMT leaders are able to accurately measure beyond the number of decimal places (out to 5) that a typical transceiver will display, however. One station participating in the 2019 spring FMT used an Elecraft KX3 and Spectrum Lab audio software. Another employed his Elecraft K3 transceiver and tuning forks to get within 1 Hz of the mark on both bands.

Some information on how to measure the frequency of a carrier is available on Marshall’s website as well as in past articles in QST. Visit the FMT-Nuts discussion group on

AddThis Sharing Buttons

Share to LinkedInLinkedInShare to RedditRedditShare to More

Call Sign / Name Search

Explore ARRL




The Frequency Measuring Test is competition of an acquired taste. The task is to measure, within two minutes, the frequency of an amateur radio signal being sent from K5CM, Connie Marshall’s home version of the NIST in Muskogee, OK. This is why we like amateur radio so much, everybody has his, her, or their own version of it. Some chat on walkie-talkies. Some lovingly maintain caesium clocks. Connie does the clocks.

— presumably David, AD8Y, or Kristina, KD8OXT, describing W8EDU’s participation in the fall 2019 FMT

We will announce the next one, probably in November, and we encourage everyone with HF receiving equipment at their location to attempt a measurement! Reach out to us if you would like guidance on preparing for the event. No caesium clocks are necessary–even a modest station can score respectively with practice!

Details on the FMT from the ARRL.

Congratulations to N8OBJ!

Congratulations to our lab director and technical advisor, John Gibbons N8OBJ, for his code related to our HamSCI research project, which just appeared in the latest version of the fldigi software package!

Update: version 4.1.11 included a bug on that prevented it from working on Windows platforms. The newest release, 4.1.12, includes fixes and should allow Windows users to take advantage of John’s code changes.

Wed Apr 1 2020 - Version 4.1.11

  *** Bug fix release ***

    * segmentation fault fix
      - change cwio_morse to *cwio_morse


  analysis mode
    * changes to data file output - submitted by John Gibbons, N8OBJ


John’s code will help us and the HamSCI community as we develop a network of citizen science receivers to study the ionosphere. It will also aid the general Amateur Radio community in making frequency estimation measurements of whatever signals are interesting to them!

Go download the latest version, and get involved!


Aidan KB3UMD