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Adjusting the Modulation Meter

G

Greatvalue1

Active Member
Aug 20, 2012
113
12
28
Phoenix, Arizona
I'm wanting to calibrate the modulation meter on a DX979 but I don't have an O-scope. My theory is that if I arbitrarily set the MAX OUTPUT (100% Mod) @ 30W, and run my signal generator through the mic @ 200-250 Hrz (for the tone of my voice), that then I'll be able to adjust the meter for 100% Mod @ 30W.

Is this even a remotely viable way of doing this for my own rig, until of course I can afford to buy and learn the right way to do it?
 

Nope.
100% modulation can only truly be gauged by seeing it on a scope. I do not trust meters, as they are not accurate nor reliable/consistent. Meters can only give you an approximation. Eye candy.
 
Robb said:
Nope.
100% modulation can only truly be gauged by seeing it on a scope. I do not trust meters, as they are not accurate nor reliable/consistent. Meters can only give you an approximation. Eye candy.
Click to expand...

I was expecting just an approximation. Just trying to figure out how to do things on my own, that's all.

1: Don't have an O-scope
2: Can't afford an O-scope
3: Don't know how to use an O-scope
 
no scope

I don't have a scope either. I bought a Redman's CB modulation meter,found a 1K tone on You Tube,plugged a amplified mini speaker into my BB Torch 9800 and adjusted my 959's modulation meter. But now my 959 is on the way back from DTB's after letting him touch it with his golden nonconductive. screwdriver. I calibrated the 959's meter to reflect the reading on the Redman's.the 1K tone was an poor attempt to set the 959's modulation pot. I didn't like it so I cranked it up. I don't have a 1K voice. It's more like a 250-300hz voice. (y)
 
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Greatvalue1 said:
I was expecting just an approximation. Just trying to figure out how to do things on my own, that's all.

1: Don't have an O-scope
2: Can't afford an O-scope
3: Don't know how to use an O-scope
Click to expand...

:headbang

I'm wanting to calibrate the modulation meter on a DX979 but I don't have an O-scope. My theory is that if I arbitrarily set the MAX OUTPUT (100% Mod) @ 30W, and run my signal generator through the mic @ 200-250 Hrz (for the tone of my voice), that then I'll be able to adjust the meter for 100% Mod @ 30W.

Is this even a remotely viable way of doing this for my own rig, until of course I can afford to buy and learn the right way to do it?
 
Tiny Jesus

PLEASE STOP ADVERTISING FOR DTB ON MY THREADS!!!

WITH NO DISRESPECT TO THE MAN, I REALLY DON'T CARE WHO HE IS!!!

Now if someone doesn't know the answer, either say you don't know, or....... DON'T REPLY!!!
 
Greatvalue1 said:
F-IT, I'LL LEARN IT MYSELF.
Click to expand...

Why so touchy? Because no one will agree with your made up method for setting 100% mod?

I learned when I was still in high school that the only way to accuratly set AM modulation was with an o-scope. That's what robb told you.

Probbaly the easiest way and just as inaccurate as your method is to listen to your audio on another radio through headphones. Just say something like "ahhhhhhhhh" in your normal radio voice. Adjust the mod open until you just hear the signal flat topping (distortion) and back it off a 1/4 of a turn or until no distortion is heard.

Otherwise go to someone who has a scope and have it set the right way...or just leave it alone and run a power mic.
 
Greatvalue1 said:
I'm wanting to calibrate the modulation meter on a DX979 but I don't have an O-scope. My theory is that if I arbitrarily set the MAX OUTPUT (100% Mod) @ 30W, and run my signal generator through the mic @ 200-250 Hrz (for the tone of my voice), that then I'll be able to adjust the meter for 100% Mod @ 30W.

Is this even a remotely viable way of doing this for my own rig, until of course I can afford to buy and learn the right way to do it?
Click to expand...


"200-250 Hrz (for the tone of my voice)" you have a very very very very very very deep voice !!!!

the ratio of deadkey to swing effects modulation also . deadkeying %25 of what you cleanly swing is supposed to be close to %100 . at 30 pep that will be 7 1/2 watts . lowering DK but keeping the 30 watt peak will increase modulation and raising deadkey will lower modulation .

BTW , i hear DTB is awesome !!!!
CB Radio - DTB Radio's Front Page
 
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BOOTY MONSTER said:
"200-250 Hrz (for the tone of my voice)" you have a very very very very very very deep voice !!!!


BTW , i hear DTB is awesome !!!!
CB Radio - DTB Radio's Front Page
Click to expand...

I didn't say he wasn't. What I am, is highly suspect of Lil' Yeshua's motives on this forum. He keeps dropping DTB's name on every single post without ever contributing the the true intensions of the thread. He's only been on what, 2 months, and he's already got 3 stars. (not that I care about stars)

Now, I apologize for the outburst. One persons actions don't justify another's. But, maybe my intension is to try to calibrate the radio with what I have. And I think there is a way (though not perfect) to accomplish this.

And maybe by doing this I'll be able to see the true value of an O-scope.

Remember, I'm talking about adjusting the meter, not the actual modulation of the radio.
 
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