So you want more modulation

The first thing one needs to do is understand what

modulation is and what is your carrier.!!  It is so

important that these two work together or you are

not going to have what your after when its all said

and done. You must understand what their

relationship to each other is.  Think of it this way,,,

Your carrier is your car and your modulation is you!!

The car takes you from one place to another just as

your carrier takes your mod from one place to another

or in other words from your transmitter to someone

else’s receiver. The carrier has no other reason to be

there but it must be there and it has to be in the proper

relationship to the modulation or the modulation quality

starts to drop like a rock. Just as you would not have a

engine in your car that's too big for it to be practical you

must not have your mod to carrier relation too far off

or it again wont be practical to run it that way.

Everybody has heard of the 100% modulation level rule on

your transmitter but what does that mean. It means quite

simply that your carrier has been modulated with your

voice as much as it can go without going into a over-

modulated state. This is as high as you can go and still get

the cleanest and clearest transmitter you are going to get.

The more over 100 % you go with your modulation the

more distorted your voice becomes. Our human ears are

extremely tolerable and can put up with a lot of distortion

before it becomes not understandable.  The biggest

misconception I’ve seen is for people to adjust their mod high

and the carrier low. This gives more swing as they call it but

the quality of your voice when it reaches the  other guys

receiver is far from clear. This is because your voice

characteristics have been altered substantially by the off balance

of the carrier to mod relationship. What your doing is sacrificing

Quality for quantity just so you can be really loud to the other

guy. But what good is a loud station if you sound like crap or

close to it!!! Don’t be fooled just because your meter swings way

up when you talk. There is more going on  than what meets the

eye as I’ve been trying to explain. All radios have swing no matter

what the radio is but not all radios will show it on the meter. Nor

will all meters show swing.

In today's CB world it has become common place to except a

Tweaked radio that is way overmod as sounding "good". Just as

long as they are loud to the other guy that seems to be all

that matters. A clear transmitter seems to have taken a back seat.!!

So many CB radios have come across my bench for repair with

these "MOD'S" put in them that just make the radios sound crappy.

But they meter sure does swing when you talk. I cant tell you how

many of these radios i have let the customer actually listen to his

own radio and he would tell me "I sound like that!!????" So after I

clean up the radio and let them listen to it again they are

dumfounded at the difference. Its unfortunate that some guys don’t

care how bad they sound just as long as they can reach out and

squash someone with their trashy signal.  I cant stress enough that

more mod is not the total answer. Getting inside the radio and

cutting out the mod limiter again is not the answer either. Most of

these radios can be adjusted so the limiter is not as effective and will

give you more mod without going way over modulated. Especially

radios with variable power output. When you cut the limiter and

reduce the carrier level down when you talk your carrier is being cut

off so much of the time you sound tiny and scratchy and over

modulated its just plain terrible. Then if you run a power mic with

this situation you are so close to being not understood at all some

guys will not even talk to you on the air.  If you understand what

single sideband is you’ll know that you have no output untill

you talk then your watt meter will jump way up and nobody will

understand you unless they have a sideband receiver to clarify you

in. This is almost the situation your getting yourself into when you

reduce your carrier level on your transmitter and increase the mod so

your swing is way way up there. You become almost not

understandable because your approaching a sideband status although

nobody is going to clarify you in believe me!!  I will say this about

radios that have had the mod limiter clipped. You can get away with

this to a point if you keep the mic gain at a decent level so when you

talk your voice peak's don’t go way up into the overmod territory.

This is area where the distortion likes to live. But this defeats the

purpose of cutting the limiter in the first place so you could get more

modulation. It would be to your advantage to leave the limiter in and

adjust it up so your voice peaks do not cause overmod. Then you can

turn the mic gain up full or run a power mic and live will be good!

I wanted to say something about meters too. Most meters will not

show you your true mod when your just talking in a regular voice as

because of the mechanical way they are built they physically cannot

follow your voice fast enough. By the time your voice peaks and starts

back down again the meter needle hasn't even gotten to your peak yet so

it also starts back down. In other words you have to give the meter a

constant tone so it has time to read your signal. That's why a 1 Kilohertz

tone is put into the mic so you can read your true percentage of mod.

Don’t just turn up the mic gain farther and father until the meter reads

100% because if you've cut out the limiter your way way way over

100%. The meter is only capable of giving you an average of your voice

peaks.  If you must see what your mod Is doing you have to look at your

signal on an oscilloscope or a monitor scope. This can read your carrier

and the modulation instantly so you can tell where your peaking. IT can

also show you your carrier to modulation relationship.  So what does all

this mean???  1 Don’t relay on just your watt meter to tell you what's

going on with your transmitter.  There is way more involved in your signal

than just "Swing".  Beware of technicians that promise you they can

make your radio "talk". There is more to it then just ripping out transistors

and cutting diodes and putting in "supermod kids" which by the way are

overrated.!!  2 Power mic's are way over rated also. You don’t need a power

mic unless you are a very soft speaking person or you have a habit of

drifting away from the mic as your speaking. Or you like to hold the mic

down by your chest or somewhere not near your mouth!! So a power mic

will help. But if you got your fm radio going or the window is down then

your going to pick up all that noise too. Remember a power mic should

only be turned up as high as you need to be heard by the person your

talking to. Turning it up even higher just because you think he will hear

you better or you’ll get out more just isn't so.  It don’t work that way.!!!

I can prove this on the scope all day long.  4 If you are lucky enough to

have your radio put on a monitor so you can see your transmit signal do

so. It will tell you so much about your signal a watt meter or a mod meter

can only dream about. If your signal looks square waved on the scope you

can be sure your signal isn't the clearest it could be and it will splatter way

up and down the band. It will be a "bleeder’ as they say. It is imparitive

that you keep your modulated carrier from  reaching the zero level on the

negative half of the audio cycle to keep out of splatterville and overmodville.

Remember the more wide open spaces you have between your peaks and

valleys on the envelope carrier the worse your signal is going to sound.

Summery

I’ve seen so many mod tricks come across my bench in the last 30 years

of repair that I could write a book. Some of them do work to a degree

and some do not work. The  latest one I’ve seen in the Galaxy boards

give you huge huge swing on the meter but the actual mod you "hear" is

less. Again i can prove this on the scope. You cannot trust just your meter,,,

it will lie to you. To make matters worse the audio quality drops like a rock.

That's what I’ve been trying to explain all along here. What the trick does is emphasize the positive or peak mod and de-emphasize the negative side.

IF you look at this on the scope ;you can see that the total percentage of

mod is about 50 or 60 even though your meter says differently. Again I can

prove this by a side by side comparison with a good radio and one that's

been Modified.  So beware of what you have done to your radio. You can

have a expensive radio that sounds like crap but has good swing if your not

careful.   The only way your going to be heard out there a greater distance

is to increase the carrier withthe modulation. Increasing just the mod only

works to a small degree then clarity starts going down the toilet.

P.s I would avoid those CB trick books. Unless you know how to

interpret the info they are giving you it could be counterproductive.

Remember what i said earlier,,, don’t just start cutting this and

cutting that.!! not good.!!