CBC International plans (was: BREAK MORE LAWS, DOUBLE YOUR FINES)

[Earl Johnston]

On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
> wrote:

>Lou Franklin can help! Pay him money and he will help you to violate federal
>regulations! But don't ask him to help you pay the fines...LOL!

While he certainly can help you break a number of federal regulations,
he also offers some things which "appear" to provide a legal
performance boost.

I don't have the background or education to know if these things are
the CB equivalent of snake oil, or if they really work. I would
appreciate the comments of the many technically proficient members of
this newsgroup.

In particular, I'm looking at the plans for his CP beam antenna and
the Digital Speech Processor kit. I have the skills required to
construct either, but not the knowledge to know if either project is
worth the effort.

Your advice and guidance would be appreciated.

Thanks,

Earl Johnston

[Frank Gilliland]

In >, Earl Johnston
> wrote:

>On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
> wrote:
>
>>Lou Franklin can help! Pay him money and he will help you to violate federal
>>regulations! But don't ask him to help you pay the fines...LOL!
>
>While he certainly can help you break a number of federal regulations,
>he also offers some things which "appear" to provide a legal
>performance boost.
>
>I don't have the background or education to know if these things are
>the CB equivalent of snake oil, or if they really work. I would
>appreciate the comments of the many technically proficient members of
>this newsgroup.
>
>In particular, I'm looking at the plans for his CP beam antenna

Circular polarization of a signal is caused by "Faraday rotation" as a signal
passes through the upper atmosphere, and occurs mainly with frequencies from 100
to 1000 MHz. Unless you plan on tuning in on satellites in that frequency range,
an antenna designed for circular polarization isn't going to do much good. IOW,
the term was probably adopted into CB mythology to describe a helical antenna,
which is no more efficient than any fiberglass stick antenna, and less efficient
than an unloaded whip.

Nearly all CB radio antennas are vertical, and therefore vertically polarized.
You are wasting your resources trying to make an antenna that's capable of
receiving both vertical and horizontal polarization. For lots of antenna
information, here's a good place to start:

http://www.ac6v.com/antprojects.htm

> and
>the Digital Speech Processor kit. I have the skills required to
>construct either, but not the knowledge to know if either project is
>worth the effort.

A speech processor is an excellent idea, but I have no idea if Lou's even works.
I certainly have some misgivings about 90% average modulation! But since you
have some electronic skills, check this out:

www.epanorama.net



=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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[Twistedhed]

From: (Earl=A0Johnston)
On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
> wrote:
Lou Franklin can help! Pay him money and he will help you to violate
federal regulations! But don't ask him to help you pay the fines...LOL!
_
>While he certainly can help you break a

>number of federal regulations,


Balderdash. Not only that,,but ludicrous. One can get information on how
to make bombs, poisons, drugs, etc. from the internet. Does the
internet become your accomplice?
Books on how to change ones ID, disappear, monkey-wrench, make
moonshine, etc., etc., have all been readily available since most can
remember. An inanimate object can have no input on one's actions,
period. Blaming the content is the same as blaming the topic, or another
person, abdicating all personal responsibility.


>he also offers some things which "appear" to

>provide a legal performance boost.

>I don't have the background or education to

>know if these things are the CB equivalent of

>snake oil, or if they really work. I would

>appreciate the comments of the many

>technically proficient members of this

>newsgroup.

>In particular, I'm looking at the plans for his CP
>beam antenna and the Digital Speech

>Processor kit. I have the skills required to

>construct either, but not the knowledge to

>know if either project is worth the effort.



Any project one does to the best of their ability is worth the effort.
Don't ever lose sight of that and don't ever allow another to tell you
different.


>Your advice and guidance would be

>appreciated.

>Thanks,

>Earl Johnston







Good luck.

[Frank Gilliland]

In >,
(Twistedhed) wrote:

>From: (Earl*Johnston)
>On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
> wrote:
>Lou Franklin can help! Pay him money and he will help you to violate
>federal regulations! But don't ask him to help you pay the fines...LOL!
>_
>>While he certainly can help you break a
>
>>number of federal regulations,
>
>
>Balderdash. Not only that,,but ludicrous. One can get information on how
>to make bombs, poisons, drugs, etc. from the internet. Does the
>internet become your accomplice?

Hey Twisty, don't you realize that you are chastising your cheerleader? After
all these years in the newsgroups, and all these people telling you that your
quoting is screwed up, and you STILL can't get it right? Dumbass.

>Books on how to change ones ID, disappear, monkey-wrench, make
>moonshine, etc., etc., have all been readily available since most can
>remember. An inanimate object can have no input on one's actions,
>period.

They most certainly can, especially when said inanimate object is controlled or
directed by a person with intentions that are less than honorable, anti-social,
or just plain malicious.

> Blaming the content is the same as blaming the topic, or another
>person, abdicating all personal responsibility.

So it was JFK's fault that he put himself in the path of a bullet, right?

>>he also offers some things which "appear" to
>
>>provide a legal performance boost.
>
>>I don't have the background or education to
>
>>know if these things are the CB equivalent of
>
>>snake oil, or if they really work. I would
>
>>appreciate the comments of the many
>
>>technically proficient members of this
>
>>newsgroup.
>
>>In particular, I'm looking at the plans for his CP
>>beam antenna and the Digital Speech
>
>>Processor kit. I have the skills required to
>
>>construct either, but not the knowledge to
>
>>know if either project is worth the effort.
>
>
>
>Any project one does to the best of their ability is worth the effort.
>Don't ever lose sight of that and don't ever allow another to tell you
>different.

Research and investigation is effort that is well spent, and that is exactly
what he was doing. Do you know how bats got around in caves before they
developed their sonar? Trial and error:

...flap, flap, flap splat! ...flap, flap, flap, splat!

Kinda like how you navigate around your lies.



=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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[Earl Johnston]

On Thu, 10 Jul 2003 07:16:18 -0700, Frank Gilliland
> wrote:

>Circular polarization of a signal is caused by "Faraday rotation" as a signal
>passes through the upper atmosphere, and occurs mainly with frequencies from 100
>to 1000 MHz. Unless you plan on tuning in on satellites in that frequency range,
>an antenna designed for circular polarization isn't going to do much good. IOW,
>the term was probably adopted into CB mythology to describe a helical antenna,
>which is no more efficient than any fiberglass stick antenna, and less efficient
>than an unloaded whip.
>
>Nearly all CB radio antennas are vertical, and therefore vertically polarized.
>You are wasting your resources trying to make an antenna that's capable of
>receiving both vertical and horizontal polarization. For lots of antenna
>information, here's a good place to start:
>
>http://www.ac6v.com/antprojects.htm


Thank you for the advice, and there is a L-O-T of information at that
site.

The circular polarized beam antenna idea is not unique to Lou
Franklin. I have seen the same concept promoted by Jo Gunn Antennas

"V Series (DX Antennas) - The V Antennas have a single feed line which
transmits circular polarity. This is the most effective way to talk DX
and hold the conditions the longest. For CB'er who wants to get the
most out of his skip talking, the V's will give the best performance
possible."

http://www.jogunn.com/jgwhich.htm

I had the impression that the Jo Gunn antennas were quality products
with solid design.

I understand that for those of you in the United States, CB is
restricted to ground wave communication. However, others in this
forum are able to talk skip without running afoul of our national
regulations.

Leaving aside the question of whether or not one should talk skip on
CB, Are Lou Franklin and Jo Gunn Antennas just blowing smoke, or is
there anything in their claims that CP beams are best for skip
talking?

[Frank Gilliland]

In >, Earl Johnston
> wrote:

>On Thu, 10 Jul 2003 07:16:18 -0700, Frank Gilliland
> wrote:
>
>>Circular polarization of a signal is caused by "Faraday rotation" as a signal
>>passes through the upper atmosphere, and occurs mainly with frequencies from 100
>>to 1000 MHz. Unless you plan on tuning in on satellites in that frequency range,
>>an antenna designed for circular polarization isn't going to do much good. IOW,
>>the term was probably adopted into CB mythology to describe a helical antenna,
>>which is no more efficient than any fiberglass stick antenna, and less efficient
>>than an unloaded whip.
>>
>>Nearly all CB radio antennas are vertical, and therefore vertically polarized.
>>You are wasting your resources trying to make an antenna that's capable of
>>receiving both vertical and horizontal polarization. For lots of antenna
>>information, here's a good place to start:
>>
>>http://www.ac6v.com/antprojects.htm
>
>
>Thank you for the advice, and there is a L-O-T of information at that
>site.
>
>The circular polarized beam antenna idea is not unique to Lou
>Franklin. I have seen the same concept promoted by Jo Gunn Antennas
>
>"V Series (DX Antennas) - The V Antennas have a single feed line which
>transmits circular polarity. This is the most effective way to talk DX
>and hold the conditions the longest. For CB'er who wants to get the
>most out of his skip talking, the V's will give the best performance
>possible."
>
>http://www.jogunn.com/jgwhich.htm
>
>I had the impression that the Jo Gunn antennas were quality products
>with solid design.
>
>I understand that for those of you in the United States, CB is
>restricted to ground wave communication. However, others in this
>forum are able to talk skip without running afoul of our national
>regulations.
>
>Leaving aside the question of whether or not one should talk skip on
>CB, Are Lou Franklin and Jo Gunn Antennas just blowing smoke, or is
>there anything in their claims that CP beams are best for skip
>talking?
>
>

Smoke city. It takes a helical antenna to radiate circular polarization. Those
fiberglass CB antennas are called 'helical' only because of how they are made,
not because they radiate circular polarization (which they don't). Want to see a
true helical antenna?

http://www.cc.edu/physics/radtel01.html

That's 30 inches long for 2400 MHz -- now can you imagine the size of a helical
for 27 MHz?

The Jo Gunn antenna you cited is called a V-yagi, and is just another variation
of the basic yagi design. Assuming it is mounted horizontally, it's polarity is
horizontal, not circular.

Here's a couple more links on antennas that I should have posted first:

http://www.tmeg.com/tutorials/antennas/antennas.htm
http://www.cebik.com



"The more we understand, the better our choices will be." -- L. B. Cebik, W4RNL





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[Richard Cranium]

Frank Gilliland > wrote in message >...
> In >, Earl Johnston
> > wrote:
>
> >On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
> > wrote:
> >
> >>Lou Franklin can help! Pay him money and he will help you to violate federal
> >>regulations! But don't ask him to help you pay the fines...LOL!
> >
> >While he certainly can help you break a number of federal regulations,
> >he also offers some things which "appear" to provide a legal
> >performance boost.
> >
> >I don't have the background or education to know if these things are
> >the CB equivalent of snake oil, or if they really work. I would
> >appreciate the comments of the many technically proficient members of
> >this newsgroup.
> >
> >In particular, I'm looking at the plans for his CP beam antenna
>
> Circular polarization of a signal is caused by "Faraday rotation" as a signal
> passes through the upper atmosphere, and occurs mainly with frequencies from 100
> to 1000 MHz. Unless you plan on tuning in on satellites in that frequency range,
> an antenna designed for circular polarization isn't going to do much good. IOW,
> the term was probably adopted into CB mythology to describe a helical antenna,
> which is no more efficient than any fiberglass stick antenna, and less efficient
> than an unloaded whip.
>
> Nearly all CB radio antennas are vertical, and therefore vertically polarized.
> You are wasting your resources trying to make an antenna that's capable of
> receiving both vertical and horizontal polarization. For lots of antenna
> information, here's a good place to start:

I'd like to be there when you tell that to Avanti, makers of the
PDL-II and Moonraker series of antennas, which feature selectable
horizontal and vertical polarization! I think they would laugh at you,
Frankie, as will the many owners of those antennas.

> http://www.ac6v.com/antprojects.htm
>
> > and
> >the Digital Speech Processor kit. I have the skills required to
> >construct either, but not the knowledge to know if either project is
> >worth the effort.
>
> A speech processor is an excellent idea, but I have no idea if Lou's even works.
> I certainly have some misgivings about 90% average modulation!

What? A "commercial broadcast engineer" that can't look at a schematic
and know whether the circuit works as advertised or not? "90% average
modulation" would be great on AM (ask a real commercial radio
engineer, Frankie; they use 'em all the time), but when the operator
isn't saying anything there'd be a rather obnoxious noise transmitted
as the circuit searches for anything to keep the modulation at 90%. As
witness the BBC some years ago, until they learned to turn down the
processing.

But why don't you know this IF you're really a commercial broadcast
engineer as you claimed?

[Frank Gilliland]

In >,
(Richard Cranium) wrote:

>Frank Gilliland > wrote in message >...
>> In >, Earl Johnston
>> > wrote:
>>
>> >On Wed, 09 Jul 2003 19:30:37 -0700, Frank Gilliland
>> > wrote:
>> >
>> >>Lou Franklin can help! Pay him money and he will help you to violate federal
>> >>regulations! But don't ask him to help you pay the fines...LOL!
>> >
>> >While he certainly can help you break a number of federal regulations,
>> >he also offers some things which "appear" to provide a legal
>> >performance boost.
>> >
>> >I don't have the background or education to know if these things are
>> >the CB equivalent of snake oil, or if they really work. I would
>> >appreciate the comments of the many technically proficient members of
>> >this newsgroup.
>> >
>> >In particular, I'm looking at the plans for his CP beam antenna
>>
>> Circular polarization of a signal is caused by "Faraday rotation" as a signal
>> passes through the upper atmosphere, and occurs mainly with frequencies from 100
>> to 1000 MHz. Unless you plan on tuning in on satellites in that frequency range,
>> an antenna designed for circular polarization isn't going to do much good. IOW,
>> the term was probably adopted into CB mythology to describe a helical antenna,
>> which is no more efficient than any fiberglass stick antenna, and less efficient
>> than an unloaded whip.
>>
>> Nearly all CB radio antennas are vertical, and therefore vertically polarized.
>> You are wasting your resources trying to make an antenna that's capable of
>> receiving both vertical and horizontal polarization. For lots of antenna
>> information, here's a good place to start:
>
>I'd like to be there when you tell that to Avanti, makers of the
>PDL-II and Moonraker series of antennas, which feature selectable
>horizontal and vertical polarization! I think they would laugh at you,
>Frankie, as will the many owners of those antennas.

I would like you to be there, too. And who knows -- if you can keep your mouth
shut and your mind open you might actually learn something.

>> http://www.ac6v.com/antprojects.htm
>>
>> > and
>> >the Digital Speech Processor kit. I have the skills required to
>> >construct either, but not the knowledge to know if either project is
>> >worth the effort.
>>
>> A speech processor is an excellent idea, but I have no idea if Lou's even works.
>> I certainly have some misgivings about 90% average modulation!
>
>What? A "commercial broadcast engineer" that can't look at a schematic
>and know whether the circuit works as advertised or not?

Not when you have four high-gain, high input-Z OP-amps on the same chip, all
inverting, all DC isolated on both the inputs and outputs, and all outputs are
unloaded. IOW, any one of them could start oscillating at any time. Or, like I
said, the thing may not even work at all because it might lock up on power up.
As far as the "processing" is concerned, it's nothing more than a clipper. The
whole thing can be done much more easily with a few discretes, and I would
certainly have much more confidence in the circuit.

> "90% average
>modulation" would be great on AM (ask a real commercial radio
>engineer, Frankie; they use 'em all the time),

Considering that the circuit is nothing more than a preamp and clipper, I have
no idea where he gets the idea that it will achieve 90% average modulation. And
in case you missed class, any form of compression and/or clipping is a form of
distortion; i.e, more compression equals more distortion. Years ago, some AM
broadcast stations would crank up the compression to the point where the sound
quality was offensive, but that's rarely done anymore.

> but when the operator
>isn't saying anything there'd be a rather obnoxious noise transmitted
>as the circuit searches for anything to keep the modulation at 90%. As
>witness the BBC some years ago, until they learned to turn down the
>processing.

You are professing your ignorance yet again -- noise gates have been around
almost as long as compression. And for your information, compressors and gates
are considered ancient technology in broadcasting these days, because with the
newer digital audio processors you can tailor your response curve to just about
shape you want in less than a minute via software.

>But why don't you know this IF you're really a commercial broadcast
>engineer as you claimed?

<*-plonk-*>






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[Earl Johnston]

On Mon, 14 Jul 2003 00:22:56 -0700, Frank Gilliland
> wrote:

>>Leaving aside the question of whether or not one should talk skip on
>>CB, Are Lou Franklin and Jo Gunn Antennas just blowing smoke, or is
>>there anything in their claims that CP beams are best for skip
>>talking?
>>
>>
>
>Smoke city. It takes a helical antenna to radiate circular polarization. Those
>fiberglass CB antennas are called 'helical' only because of how they are made,
>not because they radiate circular polarization (which they don't).

Thank you. Appreaciate you taking the time to explain and provide the
great links. I'm going to do a bit of study at the sites you provided.


>Want to see a true helical antenna?
>
>http://www.cc.edu/physics/radtel01.html
>
>That's 30 inches long for 2400 MHz -- now can you imagine the size of a helical
>for 27 MHz?

over 200 feet
>
>The Jo Gunn antenna you cited is called a V-yagi, and is just another variation
>of the basic yagi design. Assuming it is mounted horizontally, it's polarity is
>horizontal, not circular.

If it looks too good to be true, it probably is.


>"The more we understand, the better our choices will be." -- L. B. Cebik, W4RNL

Amen to that.

[Brainbuster]

Frank Gilliland wrote in message ...
>In >,
>(Richard Cranium) wrote:
>>
>>I'd like to be there when you tell that to Avanti, makers of the
>>PDL-II and Moonraker series of antennas, which feature selectable
>>horizontal and vertical polarization! I think they would laugh at you,
>>Frankie, as will the many owners of those antennas.
>
>I would like you to be there, too.


When one of you has a time machine, let me know.
I was under the impression that Avanti was no more.
:~)

>>> >the Digital Speech Processor kit. I have the skills required to
>>> >construct either, but not the knowledge to know if either project is
>>> >worth the effort.
>>>
>>> A speech processor is an excellent idea, but I have no idea if Lou's
even works.
>>> I certainly have some misgivings about 90% average modulation!
>>
>>What? A "commercial broadcast engineer" that can't look at a schematic
>>and know whether the circuit works as advertised or not?
>
>Not when you have four high-gain, high input-Z OP-amps on the same chip,
>all inverting, all DC isolated on both the inputs and outputs, and all
outputs
>are unloaded.


Digital speech processor?
I have details of his "DSP" - Dynamic Speech Processor, which makes claims
about a 90% average... so seems to be what is being referring to above.

Looking at the diagram, the first amp is a buffer stage, the second has a
gain of about 45 and the third a gain of about 21. From his figures for a
standard mic output, a loud whistle should produce about 6 volts into the
clipper... which is down to 500mV from the clipper into the output amp.


> IOW, any one of them could start oscillating at any time.

I assume that you do not have a copy of Lou's guide to the DSP...

<quote>
you may get self oscillation (squealing) due to the overall high gain of the
combined DSP, power mike (if used), and radio circuits
</quote>

And...

<quote>
The squeal problem is very common in newer Uniden SSB rigs
</quote>

His "cop-out" is that with "correct adjustment", this should not happen.
But, he is putting this adjustment in the hands of people who he has said
cannot even solder correctly. And how can anyone adjust it correctly with,
as he suggests, an SWR/power meter or someone listening to your signal?


> Or, like I said, the thing may not even work at
> all because it might lock up on power up.


More likely, it will fail due to poor building of the circuit.
I had someone ask me to fit one for him, which he supplied as supplied by
the shop, ready made. There were all kinds of problems, including the
screened wires not being correctly connected - they were shorted between
screen and inner wire.

Also, the version I have the details for had the LM324 fitted in place of
the LM3900. It should be noted that the LM324 is a "domestic" spec chip...
and may fail in temperatures below Zero or above +70° centigrade.
The LM2902 (-40° to +85°) or LM124 (-55 to +125°) are better.


>> "90% average
>>modulation" would be great on AM (ask a real commercial radio
>>engineer, Frankie; they use 'em all the time),
>
>Considering that the circuit is nothing more than a preamp and clipper, I
> have no idea where he gets the idea that it will achieve 90% average
> modulation.

Does he claim that *the DSP* will manage that magical 90%, or just that the
figure is possible?

<quote>
With correct speech processing, it is possible to increase the average
modulation to about 90%!
</quote>

Unless someone has seen a statement claiming that his product does that
"90%", or that the "90%" can be done without unacceptable distortion or
harmonic content... then it is nothing but sales bumf- careful wording.
Also, it says, "about 90%".

However, here is another of quote from Lou:
<quote>
Up to 15dB of clipping is quite acceptable to the ear
</quote>

The average peak to average ratio figure for the human voice is 14dB,
although some people may be higher or lower. The 90% quoted may
be for some people with a lower than average ratio.
Even then, to get such a high average, without an unacceptable level of
distortion, would be pretty tight... and certainly not possible without
using proper test equipment to adjust the device exactly.


>in case you missed class, any form of compression and/or
>clipping is a form of
>distortion; i.e, more compression equals more distortion.

Certainly with clipping, but how about a VOGAD?
If it is set to reasonable attack and decay times, there should be no
problem. However, the time delay means that it would not work the same as
clipping.


> Years ago, some AM broadcast stations
>would crank up the compression to the point where the sound
>quality was offensive, but that's rarely done anymore.

In the UK, Radio1 manages to create "offensive" audio without adding
distortion... they just play crap "music".
;~)

>> but when the operator isn't saying anything
>>there'd be a rather obnoxious noise transmitted as the
>>circuit searches for anything to keep the modulation at 90%. As
>>witness the BBC some years ago, until they learned to turn
>>down the processing.


The "searching for noise" will probably be associated with something
more complicated than the simple amp and clipper used in the
DSP... possibly a combination of VOGAD and clipping.



Brainbuster.

[Frank Gilliland]

In <3f14f684.0@entanet>, "Brainbuster" > wrote:

>Frank Gilliland wrote in message ...
>>In >,
>>(Richard Cranium) wrote:
>>>
>>>I'd like to be there when you tell that to Avanti, makers of the
>>>PDL-II and Moonraker series of antennas, which feature selectable
>>>horizontal and vertical polarization! I think they would laugh at you,
>>>Frankie, as will the many owners of those antennas.
>>
>>I would like you to be there, too.
>
>
>When one of you has a time machine, let me know.
>I was under the impression that Avanti was no more.
> :~)

Beats me. I don't keep up on antenna manufacturers or their products because
most of them only sell hype.

>>>> >the Digital Speech Processor kit. I have the skills required to
>>>> >construct either, but not the knowledge to know if either project is
>>>> >worth the effort.
>>>>
>>>> A speech processor is an excellent idea, but I have no idea if Lou's
>even works.
>>>> I certainly have some misgivings about 90% average modulation!
>>>
>>>What? A "commercial broadcast engineer" that can't look at a schematic
>>>and know whether the circuit works as advertised or not?
>>
>>Not when you have four high-gain, high input-Z OP-amps on the same chip,
>>all inverting, all DC isolated on both the inputs and outputs, and all
>outputs
>>are unloaded.
>
>
>Digital speech processor?
>I have details of his "DSP" - Dynamic Speech Processor, which makes claims
>about a 90% average... so seems to be what is being referring to above.

I'm sure it was just an honest mistake.

>Looking at the diagram, the first amp is a buffer stage, the second has a
>gain of about 45 and the third a gain of about 21.

Look again -- the first stage is a mic preamp with no input impedance matching
(IOW, it has a very high input impedance and probably picks up a lot of hash).
The second stage has variable gain, which is how he adjusts the clipping level.
It would be much easier to eliminate that stage completely, and adjust the
clipping by varying the voltage on the tail of the clipper.

> From his figures for a
>standard mic output, a loud whistle should produce about 6 volts into the
>clipper... which is down to 500mV from the clipper into the output amp.

Hmmm... "a loud whistle"... gee, wouldn't it be great if all technical
specifications could be that simple...

>> IOW, any one of them could start oscillating at any time.
>
>I assume that you do not have a copy of Lou's guide to the DSP...
>
><quote>
>you may get self oscillation (squealing) due to the overall high gain of the
>combined DSP, power mike (if used), and radio circuits
></quote>

He obviously hasn't had much experience with OP-amps. The hardest part about
working with OP-amps is making them NOT oscillate. When you have four inverting
amplifiers with high gain (open loop gain for the LM-324 is around 100 dB) mixed
with very high input impedance (we're talking giga-ohms) and no load on the
output, and when the inverting input pins are directly adjacent to the output
pins (as is the case with all four sections of the LM-324), that puppy can
probably be coaxed into oscillation by nothing more than an abstract thought.

>And...
>
><quote>
>The squeal problem is very common in newer Uniden SSB rigs
></quote>
>
>His "cop-out" is that with "correct adjustment", this should not happen.

Sure, just switch the first stage to low-gain, and turn down the clipper
adjustment (the gain of the second stage). But that defeats the purpose of the
circuit.

>But, he is putting this adjustment in the hands of people who he has said
>cannot even solder correctly. And how can anyone adjust it correctly with,
>as he suggests, an SWR/power meter or someone listening to your signal?

A dual-trace scope would be nice, and an audio signal generator would help. I
wonder if Heathkit ever sold kits for "whistle-generators"....

>> Or, like I said, the thing may not even work at
>> all because it might lock up on power up.
>
>
>More likely, it will fail due to poor building of the circuit.
>I had someone ask me to fit one for him, which he supplied as supplied by
>the shop, ready made. There were all kinds of problems, including the
>screened wires not being correctly connected - they were shorted between
>screen and inner wire.
>
>Also, the version I have the details for had the LM324 fitted in place of
>the LM3900. It should be noted that the LM324 is a "domestic" spec chip...

....that's "commercial" grade...

>and may fail in temperatures below Zero or above +70° centigrade.
>The LM2902 (-40° to +85°) or LM124 (-55 to +125°) are better.

I never found the temperature grade to be critical. Those are the guaranteed
specs, but even in extreme conditions most commercial grade chips will still
work fine.

>>> "90% average
>>>modulation" would be great on AM (ask a real commercial radio
>>>engineer, Frankie; they use 'em all the time),
>>
>>Considering that the circuit is nothing more than a preamp and clipper, I
>> have no idea where he gets the idea that it will achieve 90% average
>> modulation.
>
>Does he claim that *the DSP* will manage that magical 90%, or just that the
>figure is possible?
>
><quote>
>With correct speech processing, it is possible to increase the average
>modulation to about 90%!
></quote>
>
>Unless someone has seen a statement claiming that his product does that
>"90%", or that the "90%" can be done without unacceptable distortion or
>harmonic content... then it is nothing but sales bumf- careful wording.
>Also, it says, "about 90%".

Nice catch!

>However, here is another of quote from Lou:
><quote>
>Up to 15dB of clipping is quite acceptable to the ear
></quote>
>
>The average peak to average ratio figure for the human voice is 14dB,
>although some people may be higher or lower. The 90% quoted may
>be for some people with a lower than average ratio.

There is no absolute value to the amount of clipping that is "acceptable", let
alone intelligible. The peak-to-average volume ratio varies greatly from person
to person because people have different voice properties -- differences in
harmonics, pitch, articulation, etc. There are also differences in people's
hearing. Then there are other factors such as background noise, band noise, the
type of speaker and radio used, etc. There are WAY too many variables to make
such a broad statement like "15dB of clipping is quite acceptable".

>Even then, to get such a high average, without an unacceptable level of
>distortion, would be pretty tight... and certainly not possible without
>using proper test equipment to adjust the device exactly.

And at least a 3rd or 4th order low-pass filter after all that clipping.

>>in case you missed class, any form of compression and/or
>>clipping is a form of
>>distortion; i.e, more compression equals more distortion.
>
>Certainly with clipping, but how about a VOGAD?

Some of us old farts still call that AGC.

>If it is set to reasonable attack and decay times, there should be no
>problem. However, the time delay means that it would not work the same as
>clipping.

Which is better because you don't have all the harmonics. But the use of both is
best, since a clipper will catch any fast-rising signals that slip past the AGC.

>> Years ago, some AM broadcast stations
>>would crank up the compression to the point where the sound
>>quality was offensive, but that's rarely done anymore.
>
>In the UK, Radio1 manages to create "offensive" audio without adding
>distortion... they just play crap "music".
> ;~)
>
>>> but when the operator isn't saying anything
>>>there'd be a rather obnoxious noise transmitted as the
>>>circuit searches for anything to keep the modulation at 90%. As
>>>witness the BBC some years ago, until they learned to turn
>>>down the processing.
>
>
>The "searching for noise" will probably be associated with something
>more complicated than the simple amp and clipper used in the
>DSP... possibly a combination of VOGAD and clipping.

The noise he is describing is ambient and/or preamp noise. It can be heard when
the maximum gain is set too high or there is no noise gating.





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