Is this normal for freeDV or it is a noise background from laptop combined with a bug in program ?

[Nokia808]

Hello !

Please look carefully for the attached video. I set power from my station ICOM7100 at 50 Watts. "TX attenuation" at ZERO dB, so full push will reach to station by my voice. Sensitivity of BUILT-IN mic of laptop at maximum. BUT, the following are happened:

1) as you see, by watt-meter of my manual tuner COMET CAT-300, power meter never touch 50 Watts. It is at approximately just 25 Watts.

2) meter of power of tuner jump to about 25 Watts level just by activating PTT even if I do not talk any thing, & remain so whatever PTT remain activated.

3) there is slight up & down movement in power meter of tuner even if I do not talking - see last part of video when I stopped from talking BEFORE inactivated PTT (meter of power never started to fail down unless after inactivated PTT at end of video record).

Is this normal ? One of my college said to me that it seem the mic of laptop not received my sound & the 25 Watts level is due to noise background from laptop !

Please your kind help.

https://github.com/drowe67/freedv-gui/assets/25375330/85efdf01-85cd-4d5c-a165-0b2cc2652203

[tmiw]

Yeah, it's normal for there to be power even when you're not speaking (as well as the meter varying by a small amount in either direction) as there's always a data stream being transmitted. This is similar to what happens with other data modes, even if you're transmitting all zeroes.

Re: power output, it may read a bit differently depending on whether your meter is reporting peak power or average power. It reporting the latter probably explains why it's not reporting 50W.

Hope this helps!

[Nokia808]

You solved 3/4 of issue.

The remaining 1/4 is that watt-meter of tuner is already set by me at PEP not on AVG mode of reading ! More suspicious to me which make me thinking about a possible bug in program is that: when I tried 50 Watts RTTY mode watt-meter read 43 Watts, which is very okay for broadband transmitter. You know for broadband transmitters there is a loss in power as long as you ascend in frequency ..... In my ICOM when I transmit 100 Watts RTTY during manual tuning on 160 mb Watt-meter read 100 Watts, but at 10 mb it read 85 Watts .... this is expected. But, 25 Watts for 50 Watts no ! It should be 43 Watts on 20 mb , isn't it or I'm wrong ?

For that I will leave this issue opened.

[Tyrbiter]

If you are using 700D mode then the peak to average power ratio is 4dB, so 50W peak could easily display as 20-25W average.

[Nokia808]

@Tyrbiter

Watt-meter is set on PEP not on AVG. It is reporting PEP !

[Tyrbiter]

It will depend on the time constant of the meter, the definition of PEP is power over 1 RF cycle, but here the meter is measuring an OFDM signal with 700 bits/s sub-carriers, the sub-carriers are not all in phase simultaneously.

It's similar to voice peaks on SSB, the meter shows speech peaks but does not display power over 1 RF cycle.

[tmiw]

I looked at the video again and something is definitely off. The IC-7100 does seem to be reading close to 50W output as expected while the external power meter may possibly be reading significantly higher?

At least I think so, anyway, based on my interpreting the "0.5K", "1K", etc. as 500W, 1000W, etc. respectively. I think it'll help if you can set the external meter to the smaller scale (the one that seems to go up to 30W) and also set the IC-7100 to 25-30W output.

BTW for the IC-705, ALC should definitely not be showing anything. I'm fairly sure this is true for the older Icom radios as well (such as the IC-7100). i.e. it should look like the following Photoshopped screenshot:

[Nokia808]

@tmiw No dear you are wrong ! COMET CAT-300 read up to 300 Watts only ! Regarding ALC reading, I think you are also wrong & your view not applied to ICOM7100. I tried to use "TX attenuation" to lower ALC reading & result was with each lowering step by "TX attenuation" the output power further diminished ! Look for following video to see what I mean & not that ALC still not at Zero (I can set it on Zero, but I didn't):

https://github.com/drowe67/freedv-gui/assets/25375330/8e539762-1318-4023-9929-7041f328c4b8

@Tyrbiter I tried both AVG & PEP reading by CAT-300. The AVG reading was lower than PEP.

Bellow is video record for AVG reading:

https://github.com/drowe67/freedv-gui/assets/25375330/cae83c32-0c20-4a26-b8fa-4a13a79fa950

Bellow is video record for PEP reading:

https://github.com/drowe67/freedv-gui/assets/25375330/2df631a0-430c-4534-9d1b-6dfeecb3441f

I think the last explanation that given by @Tyrbiter is the correct one & explain issue of reading by CAT-300 watt-meter. I'm reaching to a conclusion - please correct to me if I'm wrong - that analog Watt-meter is not suitable for FreeDV mode & better to use digital electronic Watt-meter of high quality to measure FreeDV mode power output.

---

Side away questions: 1) is it necessary on FreeDV mode to use "Is this Frequency in use ? This is YI1YJK" on behalf of audio frequency not RF ? I know that on digital modes so many stations transmit on same frequency, but I mean the tune audio frequency like 1500 Hz (asking is there any one use for example 1500 Hz). 2) there is option of reporter in setting, but say "FSK" reporter ! Is this related to FSK digital mode ?? I know that reporter should be a site on Internet .... So, what this is exactly ? Also, when I checked it, why "Text message" field above it become inactive ?

[tmiw]

COMET CAT-300 read up to 300 Watts only !

Good to know. I'm not sure 0.5K, 1K, etc. is a good way to show the 300W scale, but that's more on Comet.

Regarding ALC reading, I think you are also wrong & your view not applied to ICOM7100. I tried to use "TX attenuation" to lower ALC reading & result was with each lowering step by "TX attenuation" the output power further diminished ! Look for following video to see what I mean & not that ALC still not at Zero (I can set it on Zero, but I didn't):

Fair enough.

I think the last explanation that given by @Tyrbiter is the correct one & explain issue of reading by CAT-300 watt-meter. I'm reaching to a conclusion - please correct to me if I'm wrong - that analog Watt-meter is not suitable for FreeDV mode & better to use digital electronic Watt-meter of high quality to measure FreeDV mode power output.

I don't think it should necessarily matter what kind of power meter you use, but meters in general tend to have varying levels of inaccuracies. My original suggestion to try lower power and the lower scale to see if the meter's more accurate at lower power levels.

1. is it necessary on FreeDV mode to use "Is this Frequency in use ? This is YI1YJK" on behalf of audio frequency not RF ? I know that on digital modes so many stations transmit on same frequency, but I mean the tune audio frequency like 1500 Hz (asking is there any one use for example 1500 Hz).

It's always a good idea to listen before transmitting. I don't think it would hurt to ask in analog mode if the frequency is in use before transmitting, especially since some hams may not be familiar with FreeDV.

2. there is option of reporter in setting, but say "FSK" reporter ! Is this related to FSK digital mode ?? I know that reporter should be a site on Internet .... So, what this is exactly ? Also, when I checked it, why "Text message" field above it become inactive ?

FreeDV can report to two sites: FreeDV Reporter and PSK Reporter. By enabling this, it actually causes your callsign to be encoded in a specific format in the same location as the Text Message field at the top of the Options window would be. As a result, only the Text Message field or the reporting options can be turned on and not both (hence why the Text Message field grays out when you enable reporting).

That said, I do recommend enabling the reporting options so that others can report hearing your signal (and help show that there is activity on FreeDV).

[Nokia808]

@tmiw

1) you said "Fair enough." I do not think so, because power meter of ICOM7100 itself became very low & no enough power pushed .....

2) you said "I don't think it would hurt to ask in analog mode if the frequency is in use before transmitting" I did not ask about analog (SSB) mode ! I asked about after switched into FreeDV mode ! In my mind to say "Is this AUDIO frequency in use?". My question is about AUDIO frequency not RF frequency !

3) you said "FreeDV can report to two sites: FreeDV Reporter and PSK Reporter." Do you mean that the "Text Message" field is only for https//qso.freedv.org site, while what bellow it (call sing & grid locator field beside checking box of PSK reporter) is only for PSK reporter & user can not use both of them (if check PSK reporter then will disable FreeDV reporter & Text Message) ? It is not clear !

[tmiw]

1. you said "Fair enough." I do not think so, because power meter of ICOM7100 itself became very low & no enough power pushed .....

It was more of an acknowledgement that it is behaving as you described, not whether that's actually a good thing or not.

2. you said "I don't think it would hurt to ask in analog mode if the frequency is in use before transmitting" I did not ask about analog (SSB) mode ! I asked about after switched into FreeDV mode ! In my mind to say "Is this AUDIO frequency in use?". My question is about AUDIO frequency not RF frequency !

Apologies for the confusion. That shouldn't actually be necessary since there can only be one person transmitting at a time.

3. you said "FreeDV can report to two sites: FreeDV Reporter and PSK Reporter." Do you mean that the "Text Message" field is only for https//qso.freedv.org site, while what bellow it (call sing & grid locator field beside checking box of PSK reporter) is only for PSK reporter & user can not use both of them (if check PSK reporter then will disable FreeDV reporter & Text Message) ? It is not clear !

PSK Reporter and FreeDV Reporter are only available if "Enable Reporting" is checked. For example, when unchecking "Enable Reporting", the options for those two services also gray themselves out:

However, when enabling reporting, the other reporting options become available:

Both services also need a callsign and grid square to be entered in order to function properly as FreeDV relies on being able to decode those from the on-air signal in order to perform the reporting.

[Tyrbiter]

Note that both of the Reporter options require the use of a 'reliable text' encoding which has forward error correction to ensure that the reported information is correct. The basic text information with reporting disabled is not error protected which means that any bit errors will lead to corruption in the decoded text. The error correction means that the maximum message length is reduced.

This is necessary because the reporting function is little use with erroneous information.

[Nokia808]

@tmiw

1) what these nice screenshots !! Is this UI off latest version ? Really painful ! No, such clear, nice, detailed UI on my side because I'm using old version of FreeDV ! For that I asked for flatpak ..... If my FreeDV has such clear UI I wasn't ask my question about reporter option !

2) regarding "AUDIO frequency", you said "That shouldn't actually be necessary since there can only be one person transmitting at a time." If I like to transmit at 1000 Hz & select it by moving red pointer, but there was someone - before me - calling on it but I did not copy him/her because I launched my program at time of his/her PTT-OFF after finishing last call & he/she in waiting to see if some one will replay or not. I question is about this gap. It will be very useful to ask "Is this audio frequency in use?" before calling so that he/she will replay "Yes, it is in use" & I will respond by "thank you" & changed into other frequency.

Regarding power issue tomorrow I will set tuner's meter on low (30 Watts) & test it because today I can not reach my shack .....

[tmiw]

1. what these nice screenshots !! Is this UI off latest version ? Really painful ! No, such clear, nice, detailed UI on my side because I'm using old version of FreeDV ! For that I asked for flatpak ..... If my FreeDV has such clear UI I wasn't ask my question about reporter option !

These are indeed from the latest version on my Mac with dark mode enabled. The other platforms (i.e. Windows) should look similar.

2. regarding "AUDIO frequency", you said "That shouldn't actually be necessary since there can only be one person transmitting at a time." If I like to transmit at 1000 Hz & select it by moving red pointer, but there was someone - before me - calling on it but I did not copy him/her because I launched my program at time of his/her PTT-OFF after finishing last call & he/she in waiting to see if some one will replay or not. I question is about this gap. It will be very useful to ask "Is this audio frequency in use?" before calling so that he/she will replay "Yes, it is in use" & I will respond by "thank you" & changed into other frequency.

I think this is equivalent to asking if the RF frequency is in use (which is definitely a good idea). When you double-click on 1000 Hz (for example) and transmit, you're effectively transmitting on your VFO frequency minus 500 Hz since the signal without any offset is going to be in the middle of the passband (1500 Hz). I could still be missing something, though.

[Nokia808]

@tmiw Look carefully for these 2 videos:

1st video for 30 Watts transmission FreeDV & tuner's Watt-meter set at "30 Watts range":

https://github.com/drowe67/freedv-gui/assets/25375330/ce0d6695-fe7d-43ab-b38c-06988cfbb9fe

2nd video for 30 Watts transmission RTTY & tuner's Watt-meter, also, set at "30 Watts range":

https://github.com/drowe67/freedv-gui/assets/25375330/9ab62ae1-d035-44f1-a63d-6dfb4b109908

What is your comment on this ? For RTTY is measure about 22.5 Watts, while for FreeDV much less !

---

Other question: at left side of UI there is a meter named "Level" for what it is ? I think it is for speaker sensivety of laptop, isn't it ?

[Tyrbiter]

Level shows the amplitude of the audio signal from the receiver that freedv sees, if it's too low you will get poor performance, if it's too high then you will get clipping which will also cause poorer performance. The level indicator will turn red if the audio input signal is too high.

[tmiw]

What is your comment on this ? For RTTY is measure about 22.5 Watts, while for FreeDV much less !

Are you able to try this same test again with something like WSJT-X in Tune mode? RTTY mode probably doesn't fully exercise the audio path between your computer and radio.

I'd also try running pavucontrol and seeing what the audio levels are for the FreeDV application as well as the radio sound device (probably named something like "USB Audio Codec" or similar).

[Nokia808]

...... RTTY mode probably doesn't fully exercise the audio path between your computer and radio. > >

What is the relation of PC with RTTY ?! I did not use RTTY for communication ! I did not use RTTY to call for QSO ! I only used RTTY to tune by generating signal of constant level ! Some users use FM for this purpuse. Others, like me, using RTTY. All what I did was the following:

• switched OFF "DATA" mode,
• exist FreeDV program,
• unplug USB cable from PC,
• activated RTTY mode from control pic of ICOM7100,
• finally, press PTT of mic of ICOM7100 So, PC has no relation to tuning by RTTY !

[tmiw]

...... RTTY mode probably doesn't fully exercise the audio path between your computer and radio. > >

What is the relation of PC with RTTY ?! I did not use RTTY for communication ! I did not use RTTY to call for QSO ! I only used RTTY to tune by generating signal of constant level ! Some users use FM for this purpuse. Others, like me, using RTTY. All what I did was the following:

• switched OFF "DATA" mode,
• exist FreeDV program,
• unplug USB cable from PC,
• activated RTTY mode from control pic of ICOM7100,
• finally, press PTT of mic of ICOM7100 So, PC has no relation to tuning by RTTY !

Yeah, I'm aware that RTTY doesn't involve the PC. That's why I was suggesting trying another digital mode program (such as WSJT-X for FT8/FT4/etc) and seeing if the power output looks the same as it does for FreeDV.

Actually, it's probably worth trying something wider bandwidth than FT8 (such as SSTV or Winlink) since that will make the comparison more similar. Is that possible at your station right now?

[Nokia808]

1) I used pulseAudio Volume Control to set my built-in laptop mic at suitable level. I set it at 50% to avoid "Too High Level".

2) regarding mapping of sound card, it is very okay & has no any error - see bellow:

3) today, I finished setting of JS8Call program on my Rig & made 1st experimental transmission by JS8 mode using 30 Watts. The same result as RTTY obtained with JS8 - see bellow video:

https://github.com/drowe67/freedv-gui/assets/25375330/be4339c4-c255-41ea-90a0-445ce6af9707

Now, as long as 30 Watts with RTTY & JS8 modes gave output about DOUBLE what generated by 30 Watts FreeDV, I can say with trust that FreeDV program - at least for Linux - has a significant bug ! But, as long as FreeVD version on my system is outdated one, the big question is whether this bug is still existing or fixed in last version of program ??

[Tyrbiter]

JS8 and RTTY use modulation that is constant envelope in nature, so there is no variation in transmitted level in the bandwidth that the meter measures.

freedv uses OFDM with multiple sub-carriers, each sub-carrier is separately QPSK modulated, this means that the transmitted signal does not have a constant envelope but instead varies depending on the sum of the instantaneous sub-carrier amplitudes.

freedv is working as intended, this is not a bug.

[Nokia808]

@Tyrbiter

This is very good that it is not a bug ! And this issue sent a light over something in FreeDV mode differ from other digital modes.

I will close this issue as long as it is not a bug.

[Nokia808]

Last comment: it is very painful to see such mode with such limited users ! I call CQ for long time but no one answered me ! More painful I did not copied till now any station using this mode ! No any one !

[tmiw]

Last comment: it is very painful to see such mode with such limited users ! I call CQ for long time but no one answered me ! More painful I did not copied till now any station using this mode ! No any one !

I'd give it a try this Saturday and Sunday as it's our monthly Activity Day weekend. There tends to be more people on during that time.

[Tyrbiter]

Last comment: it is very painful to see such mode with such limited users ! I call CQ for long time but no one answered me ! More painful I did not copied till now any station using this mode ! No any one !

I can only suggest that you try the Reporter page at https://qso.freedv.org/ so you can see who is active on which frequency. You can log in and use the chat facility too. The web reporter is independent of the in-program feature which is in the newer versions.