Shortwave Radiogram, del 4 al 9 de Mayo: programa 303

Shortwave Radiogram
Shortwave Radiogram

Our transmission on Saturdays, 2300-2330 UTC, 7570 kHz from WRMI Florida, has been suffering from wide-band interference on the same frequency. The interference is intermittent: sometimes it’s there, sometimes not, sometimes it lasts for several minutes, sometimes just for a few seconds. Anyway, Glenn Hauser, on his World of Radio program, reported that he was checking a shortwave frequency list, where he found “CGA984 – HF trading from Canada.”  One of its frequencies is 7570.

HF trading is high-frequency trading. The “high-frequency” does not refer to the spectrum from 3 to 30 MHz, although it does sometimes use HF radio, but rather to the fact it “uses powerful computer programs to transact a large number of orders in fractions of a second,” according to Investopedia. Radio is faster than the internet or telephone lines, by fractions of a second, and thus provides an advantage to high-frequency traders.

Benn Kobb provides this list of all the frequencies available to this HF trading operation, licensed in Canada and located in Harrow, Ontario, near Detroit. This would explain why the signal on 7570 is usually strong via SDRs in Michigan.

This is what the noise looks like on an SDR. It doesn’t look or sound like data, but there must be some method to this. I don’t think that well-defined signal at 7558 is part of the HF trading operation, but I’m not sure about that.  


The FCC and Canada’s CRTC will have to sort this out. We might experience noise on 7570 for at least one more weekend.

A video of last weekend’s Shortwave Radiogram (program 302)  is provided by Scott in Ontario (Friday 1300 UTC). The audio archive is maintained by Mark in the UK. Analysis is prepared by Roger in Germany.

Here is the lineup for Shortwave Radiogram, program 303, 4-9 May 2023, in MFSK modes as noted:

  1:36  MFSK32: Program preview
  2:42  MFSK32: Russia will remain on ISS until 2028
  6:04  MFSK64: Chicago will sell its water
10:01  MFSK64: This week’s images*
27:41  MFSK32: Closing announcements

* with image(s)

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Twitter: @SWRadiogram or (visit during the weekend to see listeners’ results)

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Shortwave Radiogram Gateway Wiki

Shortwave Radiogram Transmission Schedule

| UTC Day  | UTC Time      | Frequency        | Transmitter       |
| Friday   | 0030-0100 UTC | 9265 kHz         | WINB Pennsylvania |
| Friday   | 0530-0600 UTC | 7780 kHz         | WRMI Florida      |
| Friday   | 1300-1330 UTC | 15770 kHz        | WRMI Florida      |
| Friday   | 1500-1530 UTC | 15755 kHz DRM    | WINB Pennsylvania |
| Saturday | 0330-0400 UTC | 9265 kHz         | WINB Pennsylvania |
| Saturday | 2300-2330 UTC | 7570 kHz         | WRMI Florida      | 
| Monday   | 0800-0830 UTC | 5850 kHz         | WRMI Florida      |

The Mighty KBC transmits to Sundays at 2200-2400 UTC (5-7 pm EST) on 5950 kHz from WRMI Florida. A minute of MFSK64 is at about 2330 UTC.  Reports to Eric: . See also and

“This is a Music Show” Most of the show is a music show, but the host transmits some MFSK-64 text and image near the end of the broadcast.  It’s transmitted on WRMI, Thursdays at 0200-0300 UTC on 5850 kHz (Wednesday evening in the Americas). Also look for a waterfall ID at the beginning of the show.    @ThisIsAMusicSho

Pop Shop Radio from British Columbia, Canada, includes “a whole variety of pop music, such as records from the 1960s and 1970s that were played on Top-40 radio stations not only in North America but also on offshore radio and stations like Radio Luxembourg.” The programs now include some MFSK text and an image. Website: Twitter: @popshopradio1  Email:

Thanks for your reception reports!


Kim Andrew Elliott, KD9XB

Producer and Presenter

Shortwave Radiogram




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