That is what an over-modulated PSK-31 signal looks like on the waterfall. The green is the OMs signal, and the purple are all of his sidebands. I counted 5 of them. Do you see any other conversations going on next to them? No. You may be thinking, “Well, maybe it was a quiet night on 20M”.
Nope.. here is what that exact space looked like a few seconds after this person quit splattering all over the band…
You can see two strong signals and 5 other, weak signals. The person responding to mister splatter was one of the two weak ones in the middle. The other ‘strong’ signals couldn’t even be seen before due to the over modulation.
As you can see, getting your transmit levels set correctly is important.
“Well, I only transmit at 30W”, you say. Guess what, it isn’t just about power. You can have an ugly, fat signal at lower power… and can have a perfectly clean signal at 50W or even 100W, although there is no good reason to run with that much power on PSK31 from what I have seen.
“OK, so how do I fix it?”
I’m glad you asked. I will walk you through what you need to do if you have a Yaesu FT857d or a FT897 (same menus, etc) and HRD/DM780.
- Press and hold the FUNC button on your radio. You should see Menu Mode No-xxx displayed.
- Scroll through the xxx using the Select knob until you see 001, EXT MENU. Use your VFO/Tune knob to change to ON if it is OFF.
- Use the Select knob and Tuning knob to ensure you have the following values:
- Menu 20 – CAT/LIN/TUN = CAT
- Menu 37 – DIG GAIN = 50
- Menu 38 – DIG MODE = PSK31-U
- Menu 40 – DIG VOX = 0
- Menu 74 – PROV LEVEL = 0
- Menu 75 – RF POWER SET = 30W (you can adjust this later from HRD if you want, just don’t set it above 50W, please)
- Press and hold FUNC button again to exit to normal mode.
- Press FUNC momentarily to select the MultiFunction mode.
- Within 5 seconds, turn the Select knob until you see MFi for display settings. Press button A until the display above button B reads ALC.
The ALC meter is going to be key to adjusting your levels. It displays the amount of ALC being applied in a meter similar to S levels. However, here, you do NOT want to max it out. You do not want it to be above the line where S9 would normally be.
Next, get HRD, DM780, etc. up and running. I am going to assume you already have your TX/RX sound devices configured and that your setup is working, but just isn’t optimized.
- Inside of DM780, click on the Soundcard menu button. It looks like this (far right button):
- When you click on Soundcard, you will see the following pane opened below:
- If yours is set to Auto, go ahead and click on the TX radio button, so you see something like:
Your level is probably pretty high, like 50 or more. We will come back to this in a minute.
- You can click on Options, and it will take you to the Soundcard Settings where you specified what sound devices to use for transmit and receive. I recommend that you adjust your Output/Transmit device to 100% for consistency purposes. Note that if this is the same device that you use for normal Windows sounds, that you might have to adjust this again in the future since your main Windows volume control might be tied to this device. Keep it at maximum when you are using PSK-31.
- Next up, set the mode of your Yaesu to DIG in HRD.
- Lastly, adjust your Transmit level down to about 10 (using the Transmit slider we turned on in DM780 above) and begin transmitting. I assume you have a TEST script set up with your callsign.
- *Watching the ALC meter on your radio while transmitting, slowly adjust the Transmit Level slider up. Do NOT exceed the middle mark that would normally indicate S9. I usually see that mark, and back my level down by a couple of numeric values on the slider.
*Note: You will have to repeat this final step whenever you move around on the waterfall, so leave the Transmit level slider displayed if you have a wide enough monitor. It will save you a lot of effort.
Now you will be transmitting at the ideal levels, and not splattering all over the waterfall making it impossible for those next to you to continue their QSO!
Cheers and 73,