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Mic Gain and AlC

Discussion in 'Ham Equipment' started by Riverman71, Jan 25, 2019.

  1. Riverman71

    Riverman71 Part-time Member

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    My manual, like most, states to adjust the mic gain so that the ALC limit is not exceeded.

    Some operators prefer using the full range while others only want to see the meter move a little.



    Which is best?
     

  2. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    It depends on the radio, for my 101ZDMKIII if I jump on it and drive the ALC to near redline then the audio is very compressed and distorted. It sounds best when running with little to no movement of the meter. I also have a scope on this monitoring my audio as well and can see the distortion. When I use the 706gMkIIg the rig works best in with the ALC running in the middle of the peaks. Its a matter of trial and error to fine the best setting for you voice and radio.
     
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  3. drgrant

    drgrant Member

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    Depends on what I'm trying to do with the radio. On most modern radios the important thing is to not be doing what I call "shooting blocks" or blasting outside the
    ALC range.... but if I'm pushing the radio hard getting peaks up to 2/3rds or more is
    common, if I see overshoot off the end of the scale in testing I back it down until it stops happening.

    Another thing that gets confusing to some people, is the ALC is going to change on power levels. So for example radio is wide open, to get mid or most of the ALC deflection, I'll have to crank the mic gain up a bit. Crank the power back down, and if you don't bring the gain down too, you'll be overdriving the radio at lower output
    levels.

    The "I only like a little deflection" people likely aren't getting the full output out of their
    radio, unless its a rig with peculiar requirements etc. (like the ZD mentioned above, that would certainly qualify).

    -Mike
     
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  4. sp5it

    sp5it Master of puppets

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    Depends on radio. In my TS-870 I have separate knob to adjust ALC, not dependent on mic gain position, so I run mic gain wide open.
    Mike
     
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  5. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    upload_2019-1-25_11-16-23.png
    This is the 101ZD, Mic gain and drive along with compression level. Compression level is ALC adjust.
     
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  6. 338_MtRushmore

    338_MtRushmore Sr. Member

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    I run the ALC around mid range, but if I'm running compression or processing, I typically go real easy on it.
     
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  7. Road Squawker

    Road Squawker Sr. Member

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  8. drgrant

    drgrant Member

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    Not in my experience. Take pretty much any modern HF rig at full output on SSB, and if you're keeping ALC meter at 50% or less on most of them there's no way in hell its putting out the maximum power on a decent PEP meter. For example if I did that on my old 706mkII, you would be lucky to get 40 watts out of it at full output power. I also know this bit very well because I had a friend who was "one of those minimum deflection guys", although not by choice. He had a Shure 44? on his FT1000D, and while that mic sounded good, but it didn't drive the radio for crap, and even with the mic gain wide open at full RF power, he might have been lucky to get 125W out of a 200W radio... I go for 50%-75% when it doesn't matter (eg, local, low power) but otherwise if I'm actually trying to beef things up I try to keep it 75-90%. It's not that hard to do, and it will still sound good. The key is "setting it up so that you reliably never exceed".
     
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  9. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    i agree the 706 need a little push to full output
     
  10. tba02

    tba02 WOOF

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    Most of the ICOM radios seem to like ALC higher on the scale.
    I run my 7300 @ ~80% of the ALC range indicator.
     
  11. 543_Dallas

    543_Dallas Sr. Member

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    Go with what the manual says as a good starting point. It really does depend on the rig. The manual for my older rigs says 1/4 to 1/2 scale inside the ALC bracket and they work well this way. My anan sdr is designed to be pushed to 0db (per the manual) and does not distort when ran this way. You actually have to push it that hard for pure signal to work properly.

    For AM operation I have found some rigs sound horrible if you hit the ALC too hard. You'll have to play that one by ear.
     
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  12. drgrant

    drgrant Member

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    This is why no matter what radio or amp or whatever you have you should always hook up a monitor receiver after making huge changes, even if you just have a loose coax jumper hanging out of it or whatever with a set of headphones on it..... this will give you the true reality of your audio/signal.
     
    Shadetree Mechanic likes this.

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