Icom 7300/7610 Digital Mode ALC Zone

VE3TMT · May 18, 2018

N7XGR said: ↑

This is THE correct way to adjust and control the TX power out.
Although for the 7100, this is similar for other radios.

TX audio adjustment.
First go to Set>Connectors>USB Mod Level, set this to 20%.
Set the TX power out to 100%.
Run the WSJT-X program.
On the right side move the Pwr slider to MAX.
Position the JT windows for the next step, Right mouse click on the
speaker icon in the system tray and select Playback Devices.
Move this window so that it does not overlap the JT window.
Double click on USB Audio CODEC for it's properties.
Move this window for no overlap with JT window.
Click on the Enhancements Tab, turn off all enhancements.
Click on Levels Tab, set the slider at 50%.
In the JT program move the TX/RX cursor to 1200 Hz.
On the 7100, touch and hold the meter to have all the meters in view.
While transmitting into a dummy load, click the TUNE button in the
JT program, move the slider on the Levels Tab so that you have
100 watts, if not possible then unkey via the TUNE button.
Go back to the USB MOD level and increase this level to 30%
Again touch and hold the 7100 meter to display all meters.
Click the TUNE button again to check for 100 watts.
Readjust the Levels slider for 100 watts, the next step is important.
While still transmitting, observe the ALC meter, Lower the Levels Slider
until the last ALC bar goes out (Zero ALC reading)
On the JT program lower the Pwr slider to your desired power out.
To easily adjust this slider, left click on the slider button then use the mouse wheel
to raise or lower the slider to the desired power out. The slider on the Levels tab
can be done the same way.
At this point you have calibrated the ALC/Power out for a good
clean signal, you adjust the power out by the audio drive not by adjusting
the power out setting on the 7100.
The Levels slider for the 7100 CODEC (TX Audio) should not be touched
unless you see ALC action, this is the final point of TX audio calibration.
The TX audio adjustments are the Pwr slider in WSJT-X, the slider
on the Speakers (output) Tab and the USB MOD level in the 7100.
The TUNE button in WSJT-X is used for the TX power/audio adjustment.
Again the final point of adjustment is the slider on the Levels Tab
for the Speakers CODEC (TX Audio) and the final tweak is to lower the slider for no ALC reading.
I can achieve about 90 watts with Zero ALC on my 7100.
I never use the Mic jack for digital modes, I only use the ACC or USB connection.
The audio path goes through extra unneeded circuits via the Mic jack.

Hope this helps.

Bruce N7XGR
Click to expand...

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S50SD · Nov 4, 2020

NN4RH said: ↑

OK I can believe that having high ALC values should not distort an FT8 signal, at least on the two DSP radios that were mentioned.

But then if that is the case, that leads me to question - why do you need ALC to be non-zero in the first place - wouldn't you get just as good of a signal if the ALC was zero? So why does it have to be adjusted to "30%" ? What does that do for you (other than it being a rote "recipe"). Why not 20% ALC, or 10%, or 50%, or zero?
Click to expand...

Because with Yaesu 857D if ALC is 0 so is the output! 0 ALC = 0 watt out. 2-3 bars os ALC = full set power out.
On Icom 7300 I see that even 1 or 0 ALC produces 95% power out but going to 5-7 ALC produces 100% set power to go out. That is still in "normal" ALC zone.

Tested with 2 power meters inline and 2 mentioned RIGs. Only FT8 mode tested.
So with Yaesu set to 0 ALC no contact can be made at all since nothing comes out of the rig.
With Icom it is possible with 0 but my signal report drastically improves around ALC up to 5-6 (for example from R-14 to R-8).

Icom 7300/7610 Digital Mode ALC Zone

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