locked Re: Understanding setting the power level TS-2000 with the SignalLink


Georgina Joyce <gena@...>
 

Hello Bill,

Thank you for an educational post. However, I raised the issue because of my antenna location. I am sitting quite close to it and don't fancy washing myself and neighbours with RF. As FT8 was designed for QRP this is another reason for keeping power down. I am mindful of causing problems for my neighbours too.

Sam set the Windows side of things up for me and I am really enjoying the mode. I just wanted to be able to adjust the output. I don't know if the power slider within WSJT-X is accessible to a screen reader. We blind hams are largely restricted to those controls that QLog make accessible to us.

Thanks,

73
On 21 Sep 2020, at 14:22, Bill Somerville <g4wjs@...> wrote:

Hi Georgina,

ok, so you don't need to worry about seeing the ALC indication on your rig. You can use your power meter as measure. Modern rigs will give about 90% output, when modulated with a single tone, into a dummy load or well matched aerial, at the point where ALC just begins to rise above zero. It will then increase as the power approaches 100%. So you can easily find the amount of audio drive to just modulate your rig enough to get near to full power, which is what you should be aiming for.

There are usually several controls that effect the level of modulation with WSJT-X driving your SSB rig. You should aim to have digital level controls at 0 dB (FS), i.e. no attenuation and no gain, while setting up. For WSJT-X that means having the "Pwr" slider at maximum. Windows has an audio level mixer slider for each audio device and application pair, the one for WSJT-X connected to your selected audio output device should be set to maximum, but note that may be adding digital gain which would be very bad as the WSJT-X signal is already at maximum level so any gain at all will cause clipping. This issue is easily addressed by reducing the master level slider for the audio device to 0 dB (FS) once the application specific slider is set to maximum, the individual application sliders will automatically reduce in sync. Unfortunately the master level slider, which is at the left-hand side of the Windows audio mixer panel, does not have a scale in dB. Fortunately the same control is available from the audio playback device properties "Levels" panel, and there it can be switched to show decibels by right-clicking the slider and selecting decibels. When you reduce the master slider to 0 dB (note it may indicate 0 dB at maximum if the audio device has no gain stage) the whole set of sliders in the Windows audio mixer panel for that device will be reduced in turn. Do not go back and re-adjust the application slider on the mixer as increasing it will automatically increase the master level which you do not want or need.

Once you have the Windows side set up as above you can address any level controls on your PC to rig audio interface and in the menus of your rig. Treat these all as analog domain controls, which they probably are unless you are using an SDR transmitter. With analog controls you need to set the level to not saturate the following stage, in your case that probably means setting the rig's audio gain menu setting so that the rig gives about 90% output into a dummy load when modulated with a 1500 Hz tone (use the "Tune" button in WSJT-X to generate that), and with the rig set to maximum power.

Once you have that setup you can be certain that you are neither under-driving nor over-driving your rig. Then all that remains is to use the most convenient control to set your working output power, normally the rig's POWER control is best and easiest, but the "Pwr" slider in WSJT-X can be used as well. The key is that once you have the rest of the controls set as above, both of those controls may be set to maximum without over-driving; so you have a convenient control of power without having to stay within a part of the control's range(s).

ALC indication is not an indication of overdrive, in fact you cannot achieve 100% output from a rig without ALC indication. What ALC does do is provide an indication of how close to optimum audio drive is, assuming the audio is a single tone centred on the SBB Tx filter passband. Using a power meter is a reasonable substitute for this so long as the transmitter is connected to a well matched load. The difference between 90% output and 100% out is very small in terms of how your signal is copied by others, only a fraction of one S-point, so setting up for about 90% output is perfectly adequate, then use a convenient control, like the rig's POWER control to set the power per QSO.

73
Bill
G4WJS.

On 21/09/2020 13:39, Georgina Joyce wrote:
Hello Bill,

Yes, I have a LDG TW1 talking meter but it is not inline currently.

73


On 21 Sep 2020, at 00:42, Bill Somerville <g4wjs@...> wrote:

On 21/09/2020 00:35, Georgina Joyce wrote:
Hello All,

I am enjoying FT8 and sometimes just want to get a little more out of my station. I found the below  youtube video link that states that the power level is governed by the power level setting as well as menu 50 b. Which is, as I understand it, how much audio is fed into the carrier. I guess the numbers he refers to are those of the software meter. As they don't match those on the radio. The radio can TX 100W which is on a ratchet 20 position control. The menu is 1 - 9. So could I correlate these 2 controls to adjust my power levels? Is that what K4REF is stating? I certainly seem to have success on 10 clicks for power and 50b on 4. However, 6 clicks power and 50b on 2, doesn't seem to work. Perhaps I do need to use all that power but that is not the spirit of FT8.

As I I am a blind ham, tuning the ALC as demonstrated on the video is not an option for me. Unless I can give a sighted non ham good instruction on what to look for on the TS-2000 screen. While in transmit mode. I assume that WSJT-X has a tune button in the same way as the software demonstrated in the video?

Here's the video (Skip to 14 minutes);

https://www.youtube.com/watch?v=7G1DBs-04MM

If I am misunderstanding this process please advise. Also this also confuses me as the SignalLink also has a control for the audio to be transmitted. How do these 3 controls fit together?

73
  Georgina

Hi Georgina,

do you have a way to measure your transmitter power output?

73
Bill
G4WJS.



Georgina







Georgina


Call: M0EBP
DMR ID: 2346259
Allstar: 52178
Locater: IO83PS


Join main@WSJTX.groups.io to automatically receive all group messages.