Icom IC-9700 Power overshoot

Damn you Icom. Again, and again, and again. Yes. Alse the IC-9700 is equipped with the famous ‘power overshoot’ or ‘ALC overshoot’ issue most modern Icom transceivers have. Apparently Icom can’t get a grip on this issue. Bad news for people using transistor based amplifiers (SSPA) in SSB mode.

Since the IC-9700 had a ‘TX PWR LIMIT’ function, setting this to 7%* will prevent the amp from going in protection mode. The bad side is that the amp only running about 50% of the effective power.

* In my case I’m using a Gemini 2-500 amp with 4W drive level requirement. If your amp needs 10W input, raising the 7% to [try something like 13%] the value you need. And no. 7% does not mean 7 Watts, thus overloading. The value (percentage) isn’t linear. Measuring the (avg) output will tell you.

Update: Setting the tx-delay to 20 ms solved the issue tripping the SSPA.


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    • Steve G4HTZ on 17/04/2019 at 16:32
    • Reply

    I also use a IC-9700 with a Gemini 500 …and get no problem at all with tripping or overshoot ..mines set for 25w drive .

    Maybe worth changing the input attenuation on the Gemini .

    Several respected reviewers have stated there is not an overshoot problem on the 9700 .

    Good luck revolving the problem
    Steve G4HTZ

    1. Hi Steve,

      It’s worth trying, but I also have the problem on 23cm where the max 9700 output is 10 Watt and the input 8 Watts (tough limited).

        • Nigel G8IFN on 04/05/2019 at 10:45
        • Reply

        No problem with my IC-9700 and Gemini 23 cm amplifier. I have set the TX delay on the 9700 at 30mS.

    • Miguel Suñe Garcia on 13/05/2019 at 21:35
    • Reply

    On the 4th and 5th of May we worked the EA MAF test at 1.2 Ghz with the Gemini amplifier and 8 watts from the IC-9700, without problems for 6 hours on Saturday and 6 on Sunday, the “parrot” cq test was every 6 seconds and perfect without ploblemas.
    73 Mike, EA3TJ

  1. I Have no problems with that i use the Tajfun 1000 AMP and the problem was befor with my IC-7100 but
    the New 9700 does nothing like that….it works propperly.

    Best 73
    Peter DL6KA

    • David on 24/05/2019 at 14:13
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    i have this with the 9100 and Beko 1KW amp, any suggestions?

    My Ic9100 was purchased in 2012.

    • Vernon on 21/06/2019 at 16:33
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    I have a different problem, connected the IC-7900 to my Gemini 1.2 K linear which ran half power (15Watt input) until I switched the rig off. After switching the rig back on the display was dead and the TX/RX light came on. Cannot even do a factory reset on the rig.


    Vernon ZS6AIG

    • Andy Adams on 24/07/2019 at 12:20
    • Reply

    Hi David,

    I have a 9100 manufactured in 2018, with no ALC overshoot problems. Icom got to grips with the overshoot problem on the 9100. I know Icom modded the latter 9100’s, but do not know what they did. It would be worth contacting Icom and asking if it is a simple software mod? I run mine on 2m with a 3CX800 linear no problems throughout the range.

    73’s Andy GW0KZG

    • Tom on 03/10/2019 at 21:03
    • Reply

    You mentioned set ‘the tx delay to 20 ms’ – where is that menu option ?

    • Dave on 04/11/2019 at 12:19
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    The Gemini VHF/UHF amps use a control board where you can reduce the TX change over delay to match the relay switching time.

    Unfortunately when built, the control board is not adjusted! My 4m Gemini 4 was had originally a 35mS change over time, the relays are specified at 20mS. By adjusting VR3 on the control board I was able to set the c/o to 21mS

    73 Dave G4AON

    • David on 13/11/2019 at 01:33
    • Reply

    thanks Andy- will look into this— for now, I use the BEKO 1KW with my old Yaesu 736R.
    I did hear that they fixed the issue in 2018, and now the radio is discontinued.

    David N2SLO

    • Rafael / NN3RP on 18/09/2020 at 20:09
    • Reply

    I had had Icom tech support fix the ALC overshot in the 7410 and 9100.

    I’ve just bought two new Icoms 9700 mainly for satellite / DStar and the 7300 (still to receive on Sunday) which will be setup with SPE 1.3k Amp

    • Mike on 14/01/2022 at 15:48
    • Reply

    I just ‘popped’ one side of my BLF188XR based 2 meter amp. Just in time for the January contest, of course… GRRRRR!

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