Beisdes increasing modulation percentage from 85% to 100% gains little
in range or intelligability. Often not worth the effort. Adds about 7%
audio power into the each of the two sidebands. Even if the limiter
section of the modulator section is not disabled adding your
compressor is not going to increase the percentage of modulation. So
why waste the money to buy and install it unless you disable the
radio's internal limiter?

The original radio has the capability of getting to 85% modulation.
This 85% is by no means the average modulation... which is really
around 40% with voice signals. The VoiceMax brings the average
modulation to 100%! That means that every voice... high or low... soft
or loud... will modulate the radio at a constant 100%. I'm in full
agreement with your last statement... if your leave the radio's
limiter untouched... you will only be able to maintain a constant 85%
modulation. Granted, that is a great improvement from the original
radio modulation... but to get full advantage from VoiceMax (the
VoiceMax installation instructions are quite clear on this point)...
you need to adjust or disable the radio's limiter so you're able to
reach the 100% modualtion point. Once there... the VoiceMax has an on-
board adjustable limiter that will hold you precisely at the 100%
level. You can't do any better than that!
www.telstar-electronics.com

On Tue, 10 Jul 2007 04:21:39 -0700, Telspam Electronics
wrote in
. com:

Beisdes increasing modulation percentage from 85% to 100% gains little
in range or intelligability. Often not worth the effort. Adds about 7%
audio power into the each of the two sidebands. Even if the limiter
section of the modulator section is not disabled adding your
compressor is not going to increase the percentage of modulation. So
why waste the money to buy and install it unless you disable the
radio's internal limiter?

The original radio has the capability of getting to 85% modulation.


Unless it's an old tube-type radio, your original radio was broke.
Just about every solid-state radio built since the 1960's has the
modulation set for 95-98%. I mentioned this before, but like every
other fact I have stated that is easily verifiable, you ignored it.


This 85% is by no means the average modulation... which is really
around 40% with voice signals.


It varies as much as people have different voices and speaking styles,
but it is generally accepted to be in the 20 to 25% range (peak to
average ratio from 5:1 to 4:1).


The VoiceMax brings the average
modulation to 100%! That means that every voice... high or low... soft
or loud... will modulate the radio at a constant 100%.


Impossible, and you prove it yourself with your implementation of a
noise gate. You can push 40 to 50% with heavy filtering, and that's
about the best you can do, but it still causes moderate distortion.
Even if your "constant 100%" modulation applies only to unmuted voice,
it would be completely unintelligible. You can pick up almost any book
on radio communications and it will say the same thing.


I'm in full
agreement with your last statement... if your leave the radio's
limiter untouched... you will only be able to maintain a constant 85%
modulation. Granted, that is a great improvement from the original
radio modulation... but to get full advantage from VoiceMax (the
VoiceMax installation instructions are quite clear on this point)...
you need to adjust or disable the radio's limiter so you're able to
reach the 100% modualtion point. Once there... the VoiceMax has an on-
board adjustable limiter that will hold you precisely at the 100%
level. You can't do any better than that!


Assuming you set your processor's limiter to 100% mush, you still need
to set the output level to the radio so it doesn't overmodulate. Even
just 101% modulation means clipping; pump that with 100% average noise
and you have the potential for some serious bleedover. And there's no
way for the average user to determine the precise point at which his
radio is at 100% modulation. Radios are set at the factory for 95% to
98% modulation to allow for slight variations in tolerance that happen
during normal operation; for you to claim that your processor limits
modulation to 100% all of the time is not only absurd, it's impossible
because of the tolerance limitations of the radio.


These are the hard questions, Brian. And this is not a rant. I'll even
grant you clemency from your now broken promise not to reply to my
posts. You have no excuse not to reply.

On Jul 10, 12:28 pm, Frank Gilliland
wrote:
This 85% is by no means the average modulation... which is really
around 40% with voice signals.

It varies as much as people have different voices and speaking styles,
but it is generally accepted to be in the 20 to 25% range (peak to
average ratio from 5:1 to 4:1).

Since you have stopped your personal attack (for now), I will
certainly respond to your comments.
You are correct... I said "around 40%". You say 20-25%.
Either way... the number is far from the optimum 100% value the
VoiceMax can deliver.

The VoiceMax brings the average
modulation to 100%! That means that every voice... high or low... soft
or loud... will modulate the radio at a constant 100%.

Impossible, and you prove it yourself with your implementation of a
noise gate. You can push 40 to 50% with heavy filtering, and that's
about the best you can do, but it still causes moderate distortion.

Very possible... and the distortion is less than 1% THD.

Even if your "constant 100%" modulation applies only to unmuted voice,
it would be completely unintelligible. You can pick up almost any book
on radio communications and it will say the same thing.

You are correct that the 100% average applies to the unmuted signal...
Why would we be talking about anything else?
The audio signal is perfectly clear and has less than 1% THD.

www.telstar-electronics.com

On Tue, 10 Jul 2007 11:08:42 -0700, Telstar Electronics
wrote in
. com:

........

I met your standards, now you meet mine: Try your response again
without selectively snipping issues that you choose to ignore.

On Tue, 10 Jul 2007 11:08:42 -0700, Telstar Electronics
wrote in
. com:

On Jul 10, 12:28 pm, Frank Gilliland
wrote:
This 85% is by no means the average modulation... which is really
around 40% with voice signals.

It varies as much as people have different voices and speaking styles,
but it is generally accepted to be in the 20 to 25% range (peak to
average ratio from 5:1 to 4:1).

Since you have stopped your personal attack (for now), I will
certainly respond to your comments.
You are correct... I said "around 40%". You say 20-25%.
Either way... the number is far from the optimum 100% value the
VoiceMax can deliver.


See below.


The VoiceMax brings the average
modulation to 100%! That means that every voice... high or low... soft
or loud... will modulate the radio at a constant 100%.

Impossible, and you prove it yourself with your implementation of a
noise gate. You can push 40 to 50% with heavy filtering, and that's
about the best you can do, but it still causes moderate distortion.

Very possible... and the distortion is less than 1% THD.


Not possible. Older power amps were lucky to get as low as 1%
distortion -without- compression. Compression, by any other name, -IS-
distortion, whether it's by clipping or by AGC. You can filter out
some of the harmonics but the distortion remains -- and is evident by
a change in the output as you readily admit. As far as harmonics are
concerned, if you have a brick-wall filter at 3kHz you still pass
harmonics generated from fundamentals below 1.5kHz, which includes
most of the intelligible speech.

(Anyone who wants a primer in the audio spectrum should find a .wav
file of a standard 1kHz tone and try to duplicate it with their own
voice. Unless you are Mariah Carey, good luck!)

So even if you -think- you have filtered out 99% of the harmonics
generated by compression, think again. Only a distortion analyzer will
tell you how much THD remains.


Even if your "constant 100%" modulation applies only to unmuted voice,
it would be completely unintelligible. You can pick up almost any book
on radio communications and it will say the same thing.

You are correct that the 100% average applies to the unmuted signal...
Why would we be talking about anything else?
The audio signal is perfectly clear and has less than 1% THD.


Can't happen. If your peak-to-average 1:1 (which is required for 100%
modulation) then all ...=-ALL-=... the audio peaks are at the maximum.
With a 3kHz spectral limit, this would require an AGC response of less
than 20 uS, assuming you want the output to at least vaguely resemble
the input (that's 1/6000 with a very generous 10% response delay). The
chip you selected simply doesn't work that fast. You would need an AGC
amp with a slew rate at -least- 100 times faster than what you have.

Now assuming you have such a chip, and you did get 1:1 peak-to-average
voice power while muting everything else, your output would sound much
like dried ****. It's not hard to duplicate; just run a 10Vp-p audio
signal through a couple 1N34A's and filter at 3kHz. It will achieve
100% average modulation all the time, but it sounds like crap and is
completely unintelligible. And it ain't "less than 1% THD" -- the DA
says it's closer to 80% -after- the 3kHz filter.

If your processor has "perfectly clear" audio while at maximum
compression then I can guarantee you that it -isn't- running anywhere
close to 100% average modulation. 40% at best. And that's no better
than the AGC already built into the radio. On the other hand, if you
built what I already told you was a 'constant volume amplifier' (that
you confused with a 'voltage controlled amplifier') then your average
modulation is going to be closer to 25%.

Either way, your performance claims are contradictory and unrealistic
(i.e, impossible). At best they show ignorance of the principles used;
at worst, they show deception in marketing.

Assuming you set your processor's limiter to 100%, you still need
to set the output level to the radio so it doesn't overmodulate. Even
just 101% modulation means clipping; pump that with 100% average noise
and you have the potential for some serious bleedover. And there's no
way for the average user to determine the precise point at which his
radio is at 100% modulation. Radios are set at the factory for 95% to
98% modulation to allow for slight variations in tolerance that happen
during normal operation; for you to claim that your processor limits
modulation to 100% all of the time is not only absurd, it's impossible
because of the tolerance limitations of the radio.

I think this is the last of your comments I didn't have time to
respond to before. You are certainly correct that you need to set the
radio so it doesn't overmodulate. In the VoiceMax installation
instructions it says that for a precise modulation level, you should
use a scope. While it's true there's no perfect way to do this without
a scope... you should be able to get reasonably close by having an
assistant monitor your transmission during the adjustment. This is
also covered in the VoiceMax installation instructions. Even levels up
to 110% modulation will not cause excessive bleedover. The people you
hear on the air bleeding 20+ channels are usally running a combination
of excessive power with perhaps upward of 130% modulation. That is a
deadly splattering condition all right.

However, I don't agree with your statement that factory radios are set
to 95-98% possible modulation. There is no way there is enough margin
here to assure they will not exceed the 100%. That's why they they
normally set to around 85%. Both my Cobra radios were in that
vicinity. I have never put a factory radio on the scope and seen more
than 90%!

On Tue, 10 Jul 2007 13:00:41 -0700, Telstar Electronics
wrote in
. com:

Assuming you set your processor's limiter to 100%, you still need
to set the output level to the radio so it doesn't overmodulate. Even
just 101% modulation means clipping; pump that with 100% average noise
and you have the potential for some serious bleedover. And there's no
way for the average user to determine the precise point at which his
radio is at 100% modulation. Radios are set at the factory for 95% to
98% modulation to allow for slight variations in tolerance that happen
during normal operation; for you to claim that your processor limits
modulation to 100% all of the time is not only absurd, it's impossible
because of the tolerance limitations of the radio.

I think this is the last of your comments I didn't have time to
respond to before. You are certainly correct that you need to set the
radio so it doesn't overmodulate. In the VoiceMax installation
instructions it says that for a precise modulation level, you should
use a scope. While it's true there's no perfect way to do this without
a scope... you should be able to get reasonably close by having an
assistant monitor your transmission during the adjustment. This is
also covered in the VoiceMax installation instructions.


Such a procedure is pointless unless the assistant is monitoring on
the second and third harmonics.


Even levels up
to 110% modulation will not cause excessive bleedover.


But they will cause harmonics, especially on the television.


The people you
hear on the air bleeding 20+ channels are usally running a combination
of excessive power with perhaps upward of 130% modulation. That is a
deadly splattering condition all right.


Adjacent channel bleedover is caused by audio harmonic distortion
bypassing the 3kHz filter. RF Amplifiers only amplify the bleedover.
Modulation level is not a factor because overmodulation only creates
RF harmonics (e.g, being heard on 54MHz, 81MHz, etc.), which is also
caused by non-linear linears.


However, I don't agree with your statement that factory radios are set
to 95-98% possible modulation. There is no way there is enough margin
here to assure they will not exceed the 100%. That's why they they
normally set to around 85%. Both my Cobra radios were in that
vicinity. I have never put a factory radio on the scope and seen more
than 90%!


I have a shelf filled with CB manuals, both Sams and factory manuals.
Except for some of the old tube-type radios, the modulation adjustment
for all of them is around 95 to 98% -- I didn't pull those numbers out
of a hat. If you've never seen more than 90% then either your scope is
too slow or you need to learn how to use it properly. And that's why
scopes are not recommended for modulation alignment, which is usually
done with an RF voltmeter or demod probe, and an audio source with a
fixed amplitude and frequency (a sig-gen, not someone yelling AAAUUDIO
into the mic). You should really read some of these manuals -- some of
them also describe how to adjust the mic audio AGC circuits....

On Jul 10, 7:16 pm, Frank Gilliland
wrote:
Such a procedure is pointless unless the assistant is monitoring on
the second and third harmonics.

Frank lives in a black & white world. The real world is gray Frank...
and isn't perfect. I agree that in a perfect world... one would use a
scope to get to the target 100% modulation. In the real gray world...
not everyone has a scope.. and therefore would have to resort to the
next best method... the listening assistant. After all you always talk
about the "empirical" method being so good... are you getting away
from that thinking now?.. lol
www.telstar-electronics.com

On Wed, 11 Jul 2007 05:43:31 -0700, Telspam Electronics
wrote in
. com:

On Jul 10, 7:16 pm, Frank Gilliland
wrote:
Such a procedure is pointless unless the assistant is monitoring on
the second and third harmonics.

Frank lives in a black & white world. The real world is gray Frank...
and isn't perfect. I agree that in a perfect world... one would use a
scope to get to the target 100% modulation. In the real gray world...
not everyone has a scope.. and therefore would have to resort to the
next best method... the listening assistant. After all you always talk
about the "empirical" method being so good... are you getting away
from that thinking now?.. lol


I addressed the issues without ranting. I laid out logical arguments
in a clear and concise manner. I used verifiable facts to support my
conclusions. I posted well within the protocol that -YOU- established.
But it's clear that when you are proven wrong all you do is break from
your own protocol and go into a "sour grapes" mode of damage control.
Well, no more clemency for you, Brian. In fact, why don't you go back
to ignoring me again.... it's more fun that way.

You can get an RF probe for just about any DMM. It won't show
waveforms, but it costs a -lot- less than a scope, and in this
application is more accurate. As for a signal generator at the input,
any old audio oscillator will do, even the output of the sound card on
your computer. Just run it through a pot to get the desired voltage.
And the manual will cost you all of $10 on ebay. So you can keep your
scope and your gray world -- I prefer a little more contrast in my
reality, especially when it's easier, more accurate, and a lot less
expensive.

And BTW, I live in Washington, not California. I've stated where I
live about a jillion times since you've been in this group. Learn to
read.