[bars] Looking for software to identify digital modes

Thu Oct 2 23:14:20 CDT 2025

A correction to my last email

W1AW digital transmissions modes are RTTY, PSK31, and MFSK16

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Let's not forget about SSTV (Slow Scan TV), which is not actually a digital mode. SSTV is used to send images. SSTV is a FAX mode where the image is encoded into audio tones. Most of the SSTV activity is on 14.230 MHz. Two or 3 times a year, the International Space Station (ISS) transmits SSTV images on 145.800 MHz.
https://amsat-uk.org/beginners/iss-sstv/

Use MMSSTV to decode SSTV.
https://hamsoft.ca/pages/mmsstv.php

(If you are working 20M SSB, please stay off 14.230 MHz to keep this frequency clear for SSTV operation )

You can hear MFSK32 and MFSK64 every week on shortwave station WRMI Florida, 15.770 MHz, from 9:30 A.M. to 10:00 A.M. on Wednesdays. The weekly "Shortwave Radiogram" program is transmitted in these two digital modes.
https://swradiogram.net/

Another digital mode to look for is FreeDV. If you are listening with an SSB receiver all you will hear is noise. This is a collection of modes used to encode and decode digital voice on HF. These are all phone modes, so FreeDV is used only on the phone bands. The new RADE mode is amazing. It continues to decode down to signal levels that would be difficult to copy SSB. In my opinion, the audio quality of RADE is much better than any of the commercial digital voice modes (DMR, DStar, Fusion) used on VHF.
https://freedv.org/

Look on the Free DV reporter web page for FreeDV activity
https://qso.freedv.org/
(I would be happy to make a QSO with anyone who would like to try FreeDV)

In my previous email and this email I have mentioned the most popular modes. There are many more digital modes!
THOR22 is commonly used for traffic nets.
Olivia 8/250 is used for ragchews because it is very robust. During a QSO using Olivia 8/250 I saw the other station's signal fade and disappear from the waterfall on my IC-7300, yet the text continued to decode without a hiccup on my computer.
https://www.oliviadigitalmode.org/

Listen and listen so you can identify all of these modes by ear. If you hear an unfamiliar signal, see if FLDIGI will decode it.

   -Leandra AF1R
________________________________
From: bars <bars-bounces at w1hh.org> on behalf of Leandra MacLennan via bars <bars at w1hh.org>
Sent: Thursday, October 2, 2025 10:01 PM
To: Verhulst <verhulst at comcast.net>; JWAHAR BAMMI <jbammi at icloud.com>
Cc: CLUB BROADCAST BARS <bars at w1hh.org>
Subject: Re: [bars] Looking for software to identify digital modes

The "secret" technique to identify digital signals is to do lots of listening.

 I have done a lot of listening and can identify by ear most of the common digital signals.

FT8/FT4/JS8Call, these are the easiest to identify by their positions in the band. WSJT-X shows the frequencies where most of this operation takes place. These signals are synchronized to the clock. FT8 signals start at the top of the minute and at 30 seconds into the minute. FT4 signals are only 15 seconds long and start at second 0, 15, 30 and 45. JS8Call uses FT8, but are different frequencies that are not shown in WSJT-X. Every once in a while, a DX station will use an oddball frequency to keep their traffic off the FT8 watering holes. And they often use a special WSJT-X mode, so read up on them before trying to make a contact.

Start by listening to the ARRL digital bulletins. These are sent every weekday in three different modes: RTTY, PSK32 and MFSK16. Use FLDIGI to decode these signals. These signals sound very different from each other. After a couple sessions you will be able to identify which mode you are hearing.
https://www.arrl.org/digital-transmissions

In the 80M and 40M CW bands you will hear a lot of VARA. This is a robust digital mode with handshaking. You can identify these signals by the short and repetitive signal bursts.
VARA is heavily used for Winlink traffic, so you will see lots of VARA in the evenings on 80 and 40.
VarAC also uses VARA for data transport. The two watering holes for VarAC are 7.105 and 14.105.

And Packet is very distinctive - listen for APRS on 144.39 MHz

And FYI, all digital transmissions on all bands, with only one exception (packet on 40M), are all USB.

   -Leandra

________________________________
From: bars <bars-bounces at w1hh.org> on behalf of JWAHAR BAMMI via bars <bars at w1hh.org>
Sent: Thursday, October 2, 2025 9:18 PM
To: Verhulst <verhulst at comcast.net>
Cc: CLUB BROADCAST BARS <bars at w1hh.org>
Subject: Re: [bars] Looking for software to identify digital modes

https://www.sigidwiki.com/wiki/Signal_Identification_Guide

Is a good place to start

FLDIGI will identify most signal with an RSID

73 de ws1m
Bammi

On Oct 2, 2025, at 4:43 PM, Verhulst via bars <bars at w1hh.org> wrote:

Barsians,

There are plenty of programs that will let you hear different different digital modes offline. What I have not been able to find a program that connects to the radio and identify the currently tuned signal mode. I'm not particularly interested in decoding the signal. Anyone know of such a program?

Thanx  73s Tony W1DYS

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