RF Power

Icom 7300/7610 Adjusting RF Power Digital Modes

In Icom 7300, Icom 7610, Software by K0PIR8 Comments

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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 around 40% in this radio.

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

RF Power

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 1/2 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 between 1/2 and 3/4 scale 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 1/2 to 3/4 ALC in the ALC zone while transmitting.

We won’t need to touch this again.

WinWarbler

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.

Fldigi

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.

 

Conclusion

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

Many have reported the Icom 7300 and 7610 can still maintain a clean signal with the ALC at max of the ALC scale. I have chosen to stay within the ALC zone between 1/2 and 3/4 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

Sources:

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

Comments

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

  2. 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

    1. Author

      Hi Peter,

      Just before the article posted I was testing the 7300 settings and it is a little different than the Icom 7610. I needed to adjust the USB MOD Level to 40% or a little more to achieve what I was doing with the 7610 at 30%. I also noticed the 7300 still has a little fluctuation in ALC when going from 20 watts to 70 watts using the RF Power (MULTI) knob. So it is a little fussier than the 7610.

      No doubt settings will vary from station to station.

      I ran no ALC for a long time on the 7300 and I made a lot of contacts and got good reports which I am sure you are getting. No distortion.

      The CI-V Echo back is needed for some of the programs I am using. Particularly MacLoggerDX a while back. There was another too, but I can’t think of it now. The default OFF works for most everything and having it ON doesn’t seem to affect much but a couple of programs that I’ve seen. If you don’t have any problems, stick with it OFF.

      Thanks for commenting and your information, I appreciate it.

      73,

      Rich, K0PIR

  3. 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?

    1. Author

      Hi David,

      Nice to hear from you and that is my thinking too, it’s better to be safe.

      The 7300 and 7610 are not like the traditional transceivers. Basically, they process the signal different than traditional transceivers. AB4OJ has an excellent report on it. See IC-7300 User Evaluation & Test Report.

      Many of the Hams I know using the 7300 and 7610 report no distortion at 50% ALC and a few others have even commented to me that 100% is good. I think it is better to be safe, so I’ll stay around 50%. Icom just says within the ALC zone.

      I noticed that I didn’t have to use as much power when my ALC was 50% of the scale. It could have just been propagation, but I was impressed going from 30 watts to 15 watts and getting very good reports on FT8 and PSK31.

      Thank you again and I hope to hear (see) you on the air.

      Best 73,

      Rich, K0PIR

  4. 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.

    1. Author

      Hi Eivind,

      Thank you so much for reposting and again, it’s nice to hear from you. You have a very nice looking Icom 7300 page.

      That was my preferred way for a long time and I much appreciate your posting that information.

      I look very much to seeing you on FT8 someday. Best 73!

      Rich, K0PIR

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