Current FreeDV sideband convention

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Mooneer Salem

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Jun 5, 2023, 2:09:36 AM6/5/23
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Hi all,

Traditionally, FreeDV has used the same conventions as analog voice. That is, your radio gets set to lower sideband (LSB) if operating on 40 meters and below* or upper sideband (USB) otherwise. My understanding is that this supposedly makes it easier to determine whether there's an analog transmission on frequency, especially on the lower bands.

However, now that the FreeDV application has rig control and automatically switches the radio in and out of data mode depending on the state of the Analog button, does this convention still have value? Should we consider standardizing solely on USB or LSB instead? Your thoughts are definitely appreciated.

(https://github.com/drowe67/freedv-gui/issues/409 as well as related discussion in a Hamlib issue about the FT-817 and DIG mode brought this question up.)

Thanks,

-Mooneer K6AQ

* 60 meters is special and is typically upper sideband, though this depends on your country's rules.

Tony Langdon

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Jun 5, 2023, 3:00:04 AM6/5/23
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As I pointed out on Discord (repeating it here to include a possibly
wider audience for discussion), the convention of using FreeDV on the
same sideband as analog SSB was for interoperability with analog users.

As you've pointed out, if the user has CAT capable equipment, then that
point is moot (and it may be simpler just to use USB all the way).
However, this leaves non CAT users out in the cold. My own HF station
at the last shack used an IC-745, which just predates the era of
computer controlled radios.

For a non CAT user, the process of switching between analog and FreeDV
on opposing sidebands would be:

Toggle mode in FreeDV.
Switch sideband on radio.
Retune by 0 to approx 3 kHx (exact value depends on the design of the
radio, and this is the most time consuming and error prone stage).

As for why we use LSB on the lower bands, unless someone is keeping some
_really_ ancient gear on air, I don't see a technical reason to keep the
convention (switchable sidebands have been a thing for over half a
century), but it persists to this day.
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JH0VEQ

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Jun 5, 2023, 7:25:49 AM6/5/23
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everyone.

Hello,
I believe that fixing to USB or LSB will reduce the chances of operating FreeDV in my country.
I think it is necessary to switch between LSB and USB in order to avoid interference with SSB stations and that there is no band plan to operate FreeDV yet.
Interference occurs in the congested 40m band in narrow areas in Japan.
To avoid this, it is often operated at the end of the 40m band, so LSB mode should be selected.
Since the 80m band is not a frequency that allows continuous operation, it is difficult to operate if it is fixed only to USB.

As with FT8, I don't think it's a bad idea to stick to USB when FreeDV's de facto band plan is known to many radio operators. There is a possibility.
Finally, there is a need to reapply to the Radio Regulatory Authority, and I am worried about whether it will be licensed.

thank you.
Yuuichi, JH0VEQ

2023年6月5日月曜日 16:00:04 UTC+9 Tony Langdon:

Barry Jackson

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Jun 5, 2023, 9:13:23 AM6/5/23
to digita...@googlegroups.com, Mooneer Salem
On 05/06/2023 07:09, Mooneer Salem wrote:

> Hi all,
>
> Traditionally, FreeDV has used the same conventions as analog voice.
> That is, your radio gets set to lower sideband (LSB) if operating on 40
> meters and below* or upper sideband (USB) otherwise. My understanding is
> that this supposedly makes it easier to determine whether there's an
> analog transmission on frequency, especially on the lower bands.

That is a sound reason.

> However, now that the FreeDV application has rig control and
> automatically switches the radio in and out of data mode depending on
> the state of the Analog button, does this convention still have value?

I personally do not want freedv to do anything over CAT other than
operate the PTT and*READ* the rig frequency and mode (as before
1.8.10), can this new control functionality please be made optional and
included in the settings?

> Should we consider standardizing solely on USB or LSB instead? Your
> thoughts are definitely appreciated.

I would say not. Nothing wrong with conventions. 😄

> (https://github.com/drowe67/freedv-gui/issues/409
> <https://github.com/drowe67/freedv-gui/issues/409> as well as related
> discussion in a Hamlib issue about the FT-817 and DIG mode brought this
> question up.)
>
> Thanks,
>
> -Mooneer K6AQ

Cheers,
Barry
G4MKT


Brian Morrison

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Jun 5, 2023, 1:17:41 PM6/5/23
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On Mon, 5 Jun 2023 14:10:29 +0100
Barry Jackson <meadow...@gmail.com> wrote:

> I personally do not want freedv to do anything over CAT other than
> operate the PTT and*READ* the rig frequency and mode (as before
> 1.8.10), can this new control functionality please be made optional
> and included in the settings?

A CAT frequency change is only sent to the radio if you use the
drop-down list or type in your choice of frequency in the focused entry
field, if you make changes on the radio then freedv only reads the
frequency and does nothing else.

While it would be possible to make this subject to an optional setting,
every time one is added it increases the difficulty for people to
realise it's there and understand its function.

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Brian G8SEZ

Mooneer Salem

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Jun 5, 2023, 1:25:10 PM6/5/23
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Hi all,

Actually, the mode is changed on start (or when going in/out of Analog mode), so it's not 100% accurate to say that the rig is only controlled on frequency changes. Additionally, there is logic to restore the last used frequency/mode when FreeDV stops.

Barry: If another option is added to suppress just mode changes (instead of suppressing all rig control), would that be sufficient? 

Thanks,

-Mooneer K6AQ


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Brian Morrison

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Jun 5, 2023, 1:33:04 PM6/5/23
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On Mon, 5 Jun 2023 10:24:55 -0700
Mooneer Salem <moo...@gmail.com> wrote:

> Hi all,
>
> Actually, the mode is changed on start (or when going in/out of Analog
> mode), so it's not 100% accurate to say that the rig is only
> controlled on frequency changes. Additionally, there is logic to
> restore the last used frequency/mode when FreeDV stops.

A good point, I was thinking about the frequency aspect, but yes you
are correct. Brain is slow today...

>
> Barry: If another option is added to suppress just mode changes
> (instead of suppressing all rig control), would that be sufficient?

Before 1.8.10 we switched USB/LSB mode depending on the frequency read
from the radio, it wouldn't be a good idea to prevent that would it?

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Brian G8SEZ

Brian Morrison

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Jun 5, 2023, 1:37:18 PM6/5/23
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On Mon, 5 Jun 2023 18:33:00 +0100
Brian Morrison <b...@fenrir.org.uk> wrote:

> > Barry: If another option is added to suppress just mode changes
> > (instead of suppressing all rig control), would that be sufficient?
> >
>
> Before 1.8.10 we switched USB/LSB mode depending on the frequency read
> from the radio, it wouldn't be a good idea to prevent that would it?

Or maybe it was just used to indicate wrong sideband on the main
window, I've clearly been using too many test versions :-/

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Brian G8SEZ

Mooneer Salem

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Jun 5, 2023, 1:38:50 PM6/5/23
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Correct, rig control only has been a thing since 1.8.10. Prior to that, only PTT was being controlled (with everything else being read-only).

-Mooneer K6AQ

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Brian Morrison

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Jun 5, 2023, 1:45:26 PM6/5/23
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On Mon, 5 Jun 2023 10:38:34 -0700
Mooneer Salem <moo...@gmail.com> wrote:

> Correct, rig control only has been a thing since 1.8.10. Prior to
> that, only PTT was being controlled (with everything else being
> read-only).

If you are prepared to add settings to control this, I won't complain,
but I do think that it needs to be clear and straightforward.

I only noticed today that by default my TS-890 uses width/shift for
filter control in DATA modes, normally it is high cut/low cut for
straight USB/LSB modes. This can all get confusing very easily :)

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Brian G8SEZ

Mooneer Salem

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Jun 5, 2023, 1:59:10 PM6/5/23
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Actually, thinking about it more, it seems like it'd be more intuitive to have the option simply be one that disables all rig control entirely (rather than only disabling mode changes). We'll go with that.

Next question for everyone: how many people would actually disable all rig control if given the opportunity to do so? That would govern whether it's just something in Tools->Options->Rig Control (like the existing USB/LSB vs. DIGU/DIGL option) or if it needs to be in the regular PTT configuration/Easy Setup.

-Mooneer K6AQ

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ma...@flyfast.net

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Jun 5, 2023, 2:11:47 PM6/5/23
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I’ll disable it.

 

Matt

AL0R

John D. Hays

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Jun 5, 2023, 5:21:48 PM6/5/23
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Convention for digital on HF has been USB (USB-D) for all bands, rather than the analog band split where 160-40 are LSB and 20-10 are USB.

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John D. Hays
Kingston, WA
K7VE / WRJT-215

 

Siegfried...@freenet.de

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Jun 5, 2023, 6:27:12 PM6/5/23
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We all know that.. But with freedv we use analog convention (lsb on low bands) cause some users may experiment with switching back and forth between dv and analog... And that way you do not need to move the vfo when change mode...
Dg9bfc sigi 

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Michael Lizzio

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Jun 5, 2023, 7:20:32 PM6/5/23
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Mooner,

Since we have it already and if there aren't significant changes required as FreeDV development continues my vote is to keep it.

My 2 Cents...

Mike Wa2top

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Rick, WA6III

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Jun 5, 2023, 11:56:25 PM6/5/23
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This is an interesting discussion on which sideband to use for DV or really any other digital mode.

I have used USB for SSB voice on 40 and 75m since the very early 1980's when I entered the USAF and used the 618T-2 Collins HF radios in the Lockheed C141A/B and then later on (in another job), With the Collins HFS-900S series HF radios in the Boeing 737-800/900 ETOPS (overwater) aircraft.

Both of the above radios  only allowed the use of USB  (and "AME" USB with carrier) in the 2.000-29.999 MHz range so I had no choice.   Understand the radios were absolutely "capable" of LSB and CW for that matter, they just set the radios up so that those modes were not selectable by the aircrew. (we wouldn't want to anyway)

I came to the realization that USB is used world wide for all HF SSB voice operations in the military, marine and commercial aviation.  The only users of LSB are amateurs and CB'ers.

It didn't slow me down one bit on 40 and 75m (and if the 618T-2 or HFS-900S  had been capable of 1.500-29.999,  I would have used it on 160 USB also)

I am of the opinion that if amateurs were really serious about emergency/contingency communications (using HF radio) There should be a willingness to standardize so as to be interoperable with all the other services that might need to communicate with "us"  that have radios that may have USB as the only selectable SSB voice mode.

I know this is slightly off the subject (I.E. which sideband to use for digital modes via AFSK) but it is worth noting that in general,  there is no longer a valid reason to switch sidebands based on frequency of operation.

There is a pretty good  reason to standardize with the rest of the HF communications world.  We (as a group) might be taken a little more seriously if we showed a willingness to do that.

As far as rig control,   I don't care what it does, just make it "default" to whatever the radio is set at, and allow the user to change it via a "drop-down" menu next to the frequency window.  And of course, there should also be an ON/OFF switch in the setup menus .

Cheers,

Rick WA6III

Mooneer Salem

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Jun 6, 2023, 4:14:07 AM6/6/23
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IIRC HF packet standardized on LSB, so it's not every digital mode that uses LSB. The vast majority do to my knowledge, however.

That said, as FreeDV was originally designed for amateur use, it seems more appropriate to consider amateur standards rather than what's used in other radio services. Though if someone ever needed to use FreeDV to interoperate with e.g. government agencies one day, there wouldn't be anything stopping that user from forcing use of USB.

-Mooneer K6AQ

Barry Jackson

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Jun 7, 2023, 5:31:32 AM6/7/23
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On 05/06/2023 18:58, Mooneer Salem wrote:
> Actually, thinking about it more, it seems like it'd be more intuitive
> to have the option simply be one that disables all rig control entirely
> (rather than only disabling mode changes). We'll go with that.

I assume you do NOT intend to include PTT in that?

What I would suggest is a 'read only' mode as it was before 1.8.10 as
used by some other software e.g. klog. That has two check-boxes 'Enable
hamlib' and 'Read only'.

Why would anyone want the rig frequency changed automatically when
stopping freedv?
I want control of my radio and if it's on a frequency I expect it to
stay there and not be changed to some random frequency that it may have
been using prior to freedv starting.

>
> Next question for everyone: how many people would actually disable all
> rig control if given the opportunity to do so?

Me for one :) But excluding PTT and 'read' of freq, mode etc. as
required for Reporter use.

Barry
G4MKT

Brian Morrison

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Jun 7, 2023, 6:19:27 AM6/7/23
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On Wed, 7 Jun 2023 10:31:24 +0100
Barry Jackson <meadow...@gmail.com> wrote:

> On 05/06/2023 18:58, Mooneer Salem wrote:
> > Actually, thinking about it more, it seems like it'd be more
> > intuitive to have the option simply be one that disables all rig
> > control entirely (rather than only disabling mode changes). We'll
> > go with that.
>
> I assume you do NOT intend to include PTT in that?
>
> What I would suggest is a 'read only' mode as it was before 1.8.10 as
> used by some other software e.g. klog. That has two check-boxes
> 'Enable hamlib' and 'Read only'.
>
> Why would anyone want the rig frequency changed automatically when
> stopping freedv?

This was my suggestion, perhaps I have slightly different way of
driving things, last year ago it took the hamlib guys a while to
understand that I wanted to use the currently selected VFO for freedv
because their heads were entirely full of everyone using split mode in
wsjtx. They assumed that having VFO B selected meant that I was trying
to use a reverse split setup.

We all have our idiosyncrasies.

> I want control of my radio and if it's on a frequency I expect it to
> stay there and not be changed to some random frequency that it may
> have been using prior to freedv starting.

Or maybe not a random frequency at all :)

>
> >
> > Next question for everyone: how many people would actually disable
> > all rig control if given the opportunity to do so?
>
> Me for one :) But excluding PTT and 'read' of freq, mode etc. as
> required for Reporter use.

FYI there is a new set of branches in the git repo that implement all
the PRs that are now showing up at github. Once any wrinkles are dealt
with then I expect there will be a release to tidy all this up.

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Brian G8SEZ

Mooneer Salem

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Jun 7, 2023, 7:27:40 PM6/7/23
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Correct, the new option would only impact frequency and mode control, not PTT. The current pull request for this has the option being added to the Rig Control tab in Tools->Options.

-Mooneer K6AQ

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