Icom 7300/7610 Adjusting RF Power Digital Modes

How do you adjust RF power output in digital modes like FT8 and PSK31? In the Icom manual it states, “When operating in the SSB data mode, adjust the device’s output level to be within the ALC zone.” So contrary to the old rule that ALC fluctuation is bad, that is not the case with these new SDR transceivers. I had been adjusting my power mostly with the PWR slider in some of the software programs I use. That is a good way and works perfectly fine, but the ALC will adjust too. Here’s a way to keep a consistent ALC and maintain a clean signal. Use your own judgement as to how much ALC is sufficient.

Icom 7300/7610 Menu

Both transceivers are very similar. The first setting to look at is the USB MOD Level. Currently mine is set to 30% in the 7610. It works well with all of the software programs I use, Ham Radio Deluxe DM780, WSJT-X, WinWarbler and Fldigi.

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In the 7300 it is in Menu>Set>Connectors. Look for USB MOD Level. Try 40% in this radio.

In the Icom 7610 go one menu deeper to MOD INPUT. Try around 30% – 40%.

icom 7610 usb mod

Icom 7300/7610 MULTI Knob

This is where the RF power is adjusted and it’s the only setting needed to increase or decrease RF power output. Using this method the ALC will stay the same whether running 10 watts, 50 watts or 100 watts.

Push the MULTI knob and select RF POWER with the touch of a finger. Rotate the MULTI knob and set you RF power to the desired setting. Mine is normally around 30% and I get 30 watts output.

Windows Playback Devices Nifty Fifty

One more important setting for those using Windows machines. Set the Speaker Level in Windows to 50. This 50 works great with all the software I use for digital modes.

In Windows Right-click the Speaker icon in the Windows taskbar, select Playback devices, double-click the USB Audio CODEC, select the Levels tab and adjust the Speakers to 50.

All of these adjustments are in the video below.

WSJT-X Pwr Slider

We will only use the Pwr slider in WSJT-X to adjust and set the ALC.

My slider is almost to the top of the scale. This puts my ALC at approximately 1/3 scale in the ALC zone on the radio when I transmit.

pwr slider wsjt-X

Adjust yours when tuning (using the Tune button) and keep the ALC in the ALC zone.

We won’t need to touch this again unless there’s a change in the radios USB MOD Level or the Windows Speaker Level in the USB Audio CODEC.


Ham Radio Deluxe DM780 Soundcard TX Level

The slider is almost to the top of the scale. Adjust it for within the ALC zone while transmitting.

We won’t need to touch this again.


WinWarbler doesn’t have a visible RF power slider like WSJT-X and DM780. It uses the Windows Speaker Levels setting in the USB Audio CODEC.


Like WinWarbler, Fldigi doesn’t have a visible RF Power slider.

Adjusting RF Power For Digital Modes

To adjust and set the RF Power just use the MULTI knob on the Icom 7300 and Icom 7610.

It doesn’t matter if you run 10 watts, 50 watts or 100 watts, the ALC will be consistent.

This is the beauty of this method and according to the manual and the Icom experts having ALC within the ALC zone is not a bad thing, but really what we should be looking for.

RF Power Video

The video below covers everything in this article and shows an example of good and bad signals using the Icom 7610 Audio Scope.



Your setting for the USB MOD Level may differ slightly to get the optimum ALC for each software program you use. Experiment a little.

Some Hams have reported the Icom 7300 and 7610 can still maintain a clean signal with the ALC at max of the ALC scale.

Others report 1/3 scale is best for them and they maintain a clean signal. Experiment a little.

There are different ways to adjust the RF power, but if you want to maintain a consistent ALC, try this method.

You may still prefer to use the RF power slider in the software like many Hams and there is nothing wrong with that.

Some Hams will prefer to use the software and some will like using the MULTI knob on the transceiver.

How do you adjust yours?

Thank you again for coming by and I appreciate all of the comments. If you have a question please comment below. I will do my best to answer it and your experience will undoubtedly help others as well.

Best 73!

Rich, K0PIR


Page 36 of the Icom 7610 Advanced Manual

Icom 7300 Screen Captures

Icom 7610 Screen Captures

Icom America IC-7300

Icom America Icom IC-7610

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I'm an Amateur Radio enthusiast. I love the hobby and experimenting with radios, antennas and software. On my YouTube channel I upload videos on the Icom 7300 and Icom 7610 along with Ham radio software programs. I hope to inspire people to try new things in Amateur Radio.

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2 years ago

Another fine advise which is in accordense to my findings. Thanks for the good job and 73,
Frans PA0FBR

Peter Rossin
2 years ago

Hi Rich

Thanks for a great article. On my 7300, I have the RF Output set to 50% (50 watts), my Audio Codec output set to 22 and my Acc USB AF output set to 75%. With those settings my ALC is still 0. Took a lot of fussing to get there – nice to know ALC doesn’t have to be 0.

What is the function of CI V echo back ON – I have had mine off?

Pete N1PCR

David Balcaen
2 years ago

Thank you for the informative article. I have wondered about the ALC setting and in my own use of the 7300, I have reduced the audio feed to just engage the ALC. then, as you suggest, adjust the power output with the multicontrol. I guess my approach on level control is « when in doubt, leave it out » I know this is an old school approach and may or may not be Valid. My fear is that every additional audio stage introduces some element of distortion. Again , old school thinking but I still think that way HiHi. I wonder what Icom’s reason is for suggesting such a high level of ALC?

2 years ago

Hi Rich,
Power output is always set to 100W on my IC-7300. It’s in HRD DM780 (BPSK31), SIM31 and WSJT-X programs, I’m adjusting Tx audio level to control the output power, for example to zero ALC display, when running BPSK31 and so on.

Adjust the ALC meter to 0 % of the ALC scale when running PSK31/63/125 if you want to send a clean signal (-34 IMD), with no visible unwanted sidebar pairs. This is measured with my outstanding KK7UQ IMD meter.

I use nearly the same IC-7300 menu, but if only two bars appear in the ALC display, my IMD changes from -34dB to about -18-20dB measured with my kk7uq IMD meter.

With radio set to 100 % RF Power, I have approx. 60W out at 0 % ALC display.
In analogue SSTV (MMSSTV) my ALC scale shows approx. 100 % at 100W output.

Joe Castorina
2 years ago

I am having issues with WSJT-X on 20 and 15m. With your settings I am not getting any ALC or watts out. All other bands work fine. I tested by transmitting a CQ in FT8 into a dummy load.

Have you experienced this issue or heard of it?

Joe Castorina
2 years ago
Reply to  K0PIR

Hi Rich,

I have tested the CAT and PTT in WSJT-X and it works so it shows that the USB settings are correct.

If I use the Tune feature in WSJT-X I get ALC deflection and power out on all bands.

Then I tested into a dummy load and I get between 50-75% deflection on the ALC and my Bird meter shows the correct output power on all bands except 15 and 20m which so no ALC and no output power.

I cannot figure it out. I have loaded the latest Icom drivers (downloaded yesterday) and I have triple checked every settings in the radio, application and Windows and all match what you have in place. I have even crossed referenced them with other articles which basically say the same as you.

I would understand if all the bands didn’t work but just these two, which is unfortunate since 20m is the only really active band other than 40 here.

2 years ago
Reply to  K0PIR

Well Rich, when all else fails blow everything away and start over.

So to answer your questions. Your first sentence is correct. All other bands worked fine but 15 & 20. Everything you mentioned in your 3rd sentence was set correctly.

Using Winwarbler I could send PSK31 and using MMTTY I could send RTTY.

So I reset the the radio back to default, uninstalled WSJT-X and wiped any reference in the registry, removed the Icom drivers and rebooted the machine.

I then reinstalled the application and driver. I configured the radio and all worked as it should.

Not sure what happened. I have read a couple of posts that stated that the sound card in the 7300 gets confused at times and quits functioning. I also read that the latest firmware update resolved the issue. I have had the latest update installed for a while so either it does not resolve the issue or something else was going on.

Made several contacts last night on 20m FT8 without issue. Prior to the issues on 15 & 20 everything worked ok and then in the middle of working FT8 it just quit which set me off on the troubleshooting path.

I am going to watch it closely and see if it happens again.

By the way nothing was changed in settings on the radio, application or computer from when it was working to when it stopped. That is why it was just so confusing and frustrating.

Thanks for the help. I enjoy your videos, keep up the good work.

2 years ago

Hello Rick
Well I made the final selection…. Flex 6400M vs IC-7610. I now have the big brother to my 7300, the 7610.
I used your youtube video to set up the 7610 with WSJT-X. For some reason, WSJT-X sets up both receivers when changing bands….If you have time, a video from you would be nice that just sets up WSJT-X with 7610 and no logging software like HRD or N1MM etc. I also see a youtube video where the user has two copies of WSJT-X running on a windows machine and each copy is connected to one each of the receivers. I have downloaded the current driver for 7610 and COM Ports assigned are 11 and 12. I have only one USB cable connected to USB Port in the back of the 7610. My idea is to have WSJT-X – one on 50 Mhz, the other on 20Meters

Need your expertise

2 years ago

Hi Rich,

ICOM says that when in USB-D mode the output level of the IC 7300 should be within the ALC zone.
Is this also valid when the IC 7300 is in RTTY mode?

This weekend I did some RTTY (FSK) using the IC 7300 (in RTTY mode) and MMTTY, single USB-cable,
no other (logging) program connected.
With RF Power set on 30% the ALC was about 3/4 of the scale, so a rather high ALC reading.
(Output reading on my external Kenwood AT-230: about 20 watts).
With RF Power set on 5% the ALC still was 1/2 of the scale.
IC-7300 settings: ACC/USB Output Level 40%, USB Mod Level 40%, USB Send: RTS, USB Keying RTTY: DTR.

I tried some other settings but the ALC didn’t change a lot.
Any suggestions to get the ALC down (if needed)? Is there a setting in MMTTY which can do the trick?

Today I also tried a setup with FLDIGI in mode RTTY (AFSK) and the 7300 in USB-D mode.
IC-7300 settings the same as above, but USB-Send: Off.
Windows USB-Audio Codec settings each on 50%.
In this case the ALC stayed low (only 2 or 3 little bars on the ALC-scale) with RF power at 30%.
It seems to me one has more control on the ALC when using FLDIGI (RTTY / AFSK) combined with a proper setting of the USB-Audio Codec level. This compared with MMTTY (FSK). Your opinion?

Best 73
Sjuk / PA2VS

2 years ago
Reply to  K0PIR

Hi Rich,

Thank you for your quick and reassuring reply, I was concerned about the high ALC when using MMTTY.

I only started in digital modes about 6 weeks ago, when my new IC 7300 arrived.
With the help of your informative website and videos getting started was rather easy.

I only had 2 major issues:
1. In WSJT-X sometimes the 7300 would not switch from Tx to Rx and I had some rig control error messages.
Restarting WSJT-X was then the only solution.
This was solved by setting the 7300 ‘USB Send’ to OFF (it is only set to RTS when using MMTTY).

2. Some interference signals showed up on the 7300 Spectrum Scope. This was solved by replacing the
USB cable, I now use a well shielded one.

Thanks again.

Best 73
Sjuk / PA2VS

2 years ago

Hi Rich,
I just followed your suggestions made in the tutorial/article, and it all works fine on my IC-7610, for the bands above 40m. It all stays more or less consistent on all bands with the exception of 40 & 80 meters, where the power drops down to just 20 – 25 Wts. Any idea what I did wrong? I’d like to push out at a similar amount of power like on the other higher frequency bands. Any hint would be appriciated.

2 years ago
Reply to  K0PIR

Hi Rich,

thanks for your feedback. Yes, it had a high SWR. And I noticed something strange there. My antenna is tuned (using the 7610 internal tuner) to 7.074, doing a few FT8 QSOs. I noticed that I have to re-tune every, lets say 2-3 QSOs, since the tuner doesnt seem to keep the settings for this antenna at the selected frequency. Any idea why this is the case? From my understanding, the tuner should consistently keep the settings until being tuned next time, right? Thank you so much.

2 years ago
Reply to  K0PIR

Hi Rich,

think I have found what was causing the issue. During experimentation, I had PTT Start (Menu->Set->Function->Tuner), set to ON. Once I set it back to OFF, the issue was gone and the tuner settings were stable, as expected.


Bernard Rhead
2 years ago

Hi Rich

As always thanks for all your hard work putting this site/blog together. Just one q: when you talk about the ALC zone on the 7300 do you mean the red zone on the ALC scale or the whole scale?



Bernard Rhead
2 years ago
Reply to  K0PIR

Thanks Rich – that’s great. I’m on about 50% of the red scale and all seems well!

73, Bernard.

Joe Burnham
1 year ago

Hello Rich.

No matter what I do, I am not able to get more than 25-30 watts out of the rig, as indicated by it’s metering. (This is when using ‘tune’ in FT8, JS8CALL, etc.). There is also no ALC indication.

I’ve tried every possible combination of settings with USBMOD levels, RF output levels, and USB AUDIOCODEC settings on my iMac.

Icom says that the DSP processing of the transmitted signal was the reason, despite the fact that this was happening when the software used was in TUNE mode (constant tone being sent to the radio from the iMac).

Do you have any suggestions on where I could go from here?

Thanks and 73, Joe WD4KAV

8 months ago

My ic7300 works perfectly on the FT8, mode, including 6m, but I’m trying to figure out 6m MSK144. When it transmits the power output varies wildly with corresponding fluctuations in Ic and even Vc, regardless of output % setting. Looks like a dangerous state! Any ideas?

8 months ago

Interesting. Using the identical antenna for both modes. I contacted another 7300 user who has experienced the same fluctuations on his msk144 transmissions. I also went back and checked pskr and saw I was heard all over the mid and Intermountain west so dunno.

8 months ago

Hey Rich, would you confirm that the output is steady under normal transmit conditions? Clicking on “Tune” does result in a steady output but if you call CQ or answer someone in msk144 does it still stay steady and is the ALC at zero or some other level?
Thanks, Marty W0EET

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