"Big Joe" wrote...
Sure I like the sound of clipping to a small amount.
As you know all Commercial, and Ham FM radios since the begging, has had
a CLIPPER built in followed by a Low pass filter ( Motorola used to call it
a splitter filter ) . This goes to a Deviation adjustment to feed the
modulator. Does a good job at two things. It holds the deviation (
Modulation ) to a fixed point and also clips off some of the Voice P-P
levels to help increase the average voice level.

So it Seems to sound OK to all the other FM radio users.

What you have to remember is that other FM users have much
more bandwidth to play with than CB users. The broadcast
stations have shed-loads of bandwidth to play with.

If you are using AM or SSB CB, I would certainly recommend
speech processing. But I would recommend that you avoid it
with FM CB, the 10KHz between channels is not really enough
for FM.

With a multi-mode set, I would fit one and disable it for
FM mode. I believe that would be better than lowering the
maximum deviation to allow for the increased average.

But, speaking of broadcast stations, do you know the other
trick used to get greater distance on FM broadcast? It
works a treat on FM CB, without the adjacent channel
splatter of other devices.


If I needed a Broadcast Radio quality sound then Sure
I would use a Compressor throughout the system.

Unfortunately, to get broadcast quality FM, you would need
FM broadcast bandwidth. One channel would take up most
of the CB band.

If you want a Pint, you must first get a Pint container.
But you will never get quality while the barman is giving
you the dregs and slops.


If the modulation system used in a FM radio was used in
a AM CB radio ( without using all the audio feedback crappy
AGC systems they use now ) the audio could be adjusted to
100% and then what ever mic was used the radio would not
overmodulate.

AM, FM and SSB each have their good and bad points. One
big problem with FM is that the bandwidth requirement
really doesn't suit the small CB channel spacing.
Here in the UK, we have had FM CB for over 26 years... and
the splatter has been hell. It's still going on now, even after
the government reduced the maximum allowed deviation.

I have just been listening to someone giving me a signal
of just 7 on his channel... and jumping to 6 on each of the
adjacent channels with every sound he makes.
Oh yes, and he sounds crap on the channel he is supposed
to be on. So much of his signal is going outside of the
receiver bandwidth, that the needle bounces about like
a yo-yo and far too much of his audio is lost.


So like I said I like a little of both.

The choice over which of the two systems to use really
comes down to price and either proven long-term reliability
or trust in the name.

Lou's product is reasonably priced and has proved itself
over a long time but, let's face it, it is only a basic circuit
designed to meet the needs of the majority of CB users... cheap
but effective.
Telstar's product may cost a little more and boasts better
quality**, but it is a new product without the years of
tests in the real world.

Even large manufacturers find problems with their design after
batches have gone out. I have spent many hours fixing design
errors so that a batch of products could leave by the deadline.


Similar to adding a Compressor to a FM transmitter driving
it using the mic gain to a little of clipping.

All FM transmitters are NOT born equal. What works on
one FM system may not be suitable on another.
Speech compression is fine for broadcast FM, but not for
CB FM with only 10KHz channel spacing.


Regards,
Peter.

** I have only had Lou's product on the bench. I have never
tested the Telstar product, so cannot comment on whether
it really is worth any extra cost.