Issue #1: QMX is in TX mode, but there is no output despite fldigi generating signal

SOLUTION:? "The only right channel is the right channel" (not mentioned in QMX Operation manual, though). BTW I had the same problem with TS-480 & Digirig mobile, in general this applies to any interface (USB or other) which uses only the right channel for AFSK input into the transceiver. Unlike other programs which show options like "Mono" or "L+R" when setting up soundcard (JTDX, JS8Call, VARA etc.), fldigi is not so straightforward.



Issue #2: QMX receives signal (and it can be heard in headphones), but there is no waterfall in fldigi no matter what threshold settings for the waterfall you choose. Signal level indicator in fldigi shows noise level at about -100 dB and incoming signal in peaks does not exceed minimum level needed for detection, for instance does not exceed -80 dB. This issue is very confusing due to the fact that other digi programs (such as JS8Call, which I used to test this) seem to find this signal level satisfactory, detect signals and show usual waterfall picture.

IMMEDIATE SOLUTION: on QMX open menu, Audio/AGC settings/AGC = OFF. Or, you can tweak your AGC settings until you achieve at least -50 dB audio level supplied to fldigi input.

LONG TERM SOLUTION:
?Variant 1: modify fldigi to automatically adjust for the level needed for detection (a kind of digital AGC or digital amplification, to amplify the signal to move the peak level e.g. to -20 dB for weak audio signal)
?Variant 2: modify QMX firmware to adjust output level presented to the audio interface just in the USB path (such as? shift left a couple of bits) so that the peak level is never less than, let's say, -60 dB.
(both variants would be welcome, but either one should suffice).

Yes, I know it is not good manner to tell software developers how they should do their work, I apologize! Just wanted to decrease level of frustration among the users of both fldigi and QMX :)

--
73 de Jindra OK4RM, OM0RM

Board revision V1, firmware 1.00.017.

I will update the firmware and retest.

David

On 5/16/24 10:11, ok4rm wrote:

Hi, David,
thank you for the very interesting observations. As for the left channel: Cliff, AE5ZA, mentioned that "it worked" until firmware 1.0.0.7. Which version do you have? And which board revision? Mine is V2 and started at FW version 1.0.0.14 IIRC, now I have 1.0.0.18. This issue with the right channel seems to be common to different transceivers (for me: Digirig Mobile + TS-480) and maybe, then, I have something wrong in the Windows audio setup and it just prevents any output on the left channel. I'll have to check that (if I only knew how :) ). OTOH, there seem to be many other QMX users who complain that their tcvr generates zero output on RTTY with fldigi.?

As for the CW generated as audio in QMX digi mode, I have the same experience: when VOX is ON, it transmits more or less normal CW. When I switch VOX OFF, switch to transmit using CAT command, as soon as the first audio element is finished, it switches to RX mode and does not transmit any more. This seems to be a bug, I already reported to Hans.

As for the levels, yes, I use 0 dB output level everywhere. My issue was indeed due to the right channel "not included" in fldigi.

73! Jindra

On Thu, May 16, 2024 at 03:38 PM, Dave wrote:

Good morning Jindra,

After receiving your email solutions I put my QMX on line and retested.? My findings are not the same as yours.

Issue #1: my QMX expects to receive the audio on the LEFT channel and not the RIGHT channel.



The audio drive to the QMX must be of sufficient amplitude for the QMX to detect the audio frequency.? Set the OS audio output to provide maximum drive and then set this control to 0 dB:



Testing the QMX into a dummy load and listening and decoding on an FT-710 with flrig/fldigi; the various digital modes behave thuslyL

MODE	TX	COMMENTS
TUNE	yes	?
CW	no	single dit hears and then silence
CONTESTIA 8-250	no	starting tone and then silence; CONTESTIA uses shaped tones
DOMINO-EX	partial	?
HELL	partial	only FSK 245/105/80; received raster not distinct
MFSK	no	tx ends after first tone
MT63	no	amplitude/phase modulation
OFDM	no	amplitude/phase modulation
OLIVIA	no	tx ends after first tone
PSK, QPSK, 8PSK,PSKR	no	amplitude/phase modulation
RTTY	yes	?
THOR	partial	Micro, 4, 5, 8, 11 & 16;? higher baud rates the QMX does not follow the transition
THROB	no	amplitude/frequency modulation

?
Any attempt at transmiting a leading RsID signal results in a loss of transmission immediately after the RsID signal.

Issue #2:? use flrig with fldigi


The "RF" control is simply a gain control for the QMX transceiver.? It provides a very wide range of input signal amplification.? I usually set mine between 80 and 90 depending on the band and antenna in use.

73, David

On 5/16/24 02:37, ok4rm wrote:

Issue #1: QMX is in TX mode, but there is no output despite fldigi generating signal

SOLUTION:? "The only right channel is the right channel" (not mentioned in QMX Operation manual, though). BTW I had the same problem with TS-480 & Digirig mobile, in general this applies to any interface (USB or other) which uses only the right channel for AFSK input into the transceiver. Unlike other programs which show options like "Mono" or "L+R" when setting up soundcard (JTDX, JS8Call, VARA etc.), fldigi is not so straightforward.



Issue #2: QMX receives signal (and it can be heard in headphones), but there is no waterfall in fldigi no matter what threshold settings for the waterfall you choose. Signal level indicator in fldigi shows noise level at about -100 dB and incoming signal in peaks does not exceed minimum level needed for detection, for instance does not exceed -80 dB. This issue is very confusing due to the fact that other digi programs (such as JS8Call, which I used to test this) seem to find this signal level satisfactory, detect signals and show usual waterfall picture.

IMMEDIATE SOLUTION: on QMX open menu, Audio/AGC settings/AGC = OFF. Or, you can tweak your AGC settings until you achieve at least -50 dB audio level supplied to fldigi input.

LONG TERM SOLUTION:
?Variant 1: modify fldigi to automatically adjust for the level needed for detection (a kind of digital AGC or digital amplification, to amplify the signal to move the peak level e.g. to -20 dB for weak audio signal)
?Variant 2: modify QMX firmware to adjust output level presented to the audio interface just in the USB path (such as? shift left a couple of bits) so that the peak level is never less than, let's say, -60 dB.
(both variants would be welcome, but either one should suffice).

Yes, I know it is not good manner to tell software developers how they should do their work, I apologize! Just wanted to decrease level of frustration among the users of both fldigi and QMX :)

--
73 de Jindra OK4RM, OM0RM

MODE	TX	COMMENTS
TUNE	yes
CW	no	single dit hears and then silence
CONTESTIA 8-250	no	starting tone and then silence; CONTESTIA uses shaped tones
DOMINO-EX	partial
HELL	partial	only FSK 245/105/80; received raster not distinct
MFSK	no	tx ends after first tone
MT63	no	amplitude/phase modulation
OFDM	no	amplitude/phase modulation
OLIVIA	no	tx ends after first tone
PSK, QPSK, 8PSK,PSKR	no	amplitude/phase modulation
RTTY	yes
THOR	partial	Micro, 4, 5, 8, 11 & 16;? higher baud rates the QMX does not follow the transition
THROB	no	amplitude/frequency modulation

?

On May 16, 2024, at 12:00, Bob Cameron, VK2YQA via <bob3bob3@...> wrote:

Hi Dave, more to help with your testing rather than the L-R issue.

The TX "failure" for such MFSK audio as Olivia/Contestia/Thor/MFSK/Domino/IKFP/FSQ/RSID is "fixed" by reducing the QDX (and I assume QMX) minimum samples from the 480 default to something like 120-180. I also reduce the rise/fall times (2/40) to stop the raise cosine PTT inhibit, otherwise the TX chops on and off. FM picture sub modes are generally not pretty with random like line shifts.

Minimum samples at 120 is however not low enough for Thor 56 or faster/wider. I have a series of command buttons on flrig to change this and the audio level as needed.

The TX audio still sounds a little ragged, but I have had some successful Olivia 8/250 QSO's VK>EU. One day I'll do some SDR s/n threshold testing to see of there is any decode degradation.

Cheers Bob VK2YQA

On 16/5/24 23:38, Dave, W1HKJ wrote:

MODE	TX	COMMENTS
TUNE	yes
CW	no	single dit hears and then silence
CONTESTIA 8-250	no	starting tone and then silence; CONTESTIA uses shaped tones <HK9LwHSLF0nBY0XS.png>
DOMINO-EX	partial
HELL	partial	only FSK 245/105/80; received raster not distinct
MFSK	no	tx ends after first tone
MT63	no	amplitude/phase modulation
OFDM	no	amplitude/phase modulation
OLIVIA	no	tx ends after first tone
PSK, QPSK, 8PSK,PSKR	no	amplitude/phase modulation
RTTY	yes
THOR	partial	Micro, 4, 5, 8, 11 & 16;? higher baud rates the QMX does not follow the transition
THROB	no	amplitude/frequency modulation

?