[Amps] Audio BW, *WAS* Centurion cooling...

[Joe Isabella]

Simple.  Because a "Normal" SSB signal doesn't contain enough audio content below 100Hz or so to
create the effect.  I have access to several types of analyzers such as HP (or Agilent), Rohde &
Schwartz, etc.  I work in a very large R&D center for a large mobile phone company, so I have
access to some top of the line test equipment.  I don't constantly monitor with a $100k analyzer
-- wish I could!!  But I do periodically borrow some nice stuff!!

Joe,
N3JI
--- Gary Schafer <garyschafer at comcast.net> wrote:

> Hi Joe,
> 
> How would you then explain that this "phenomenon" is not heard or 
> perceived as carrier on a normal SSB signal when tuning the signal lower 
> in frequency than where the carrier is. This converts the frequencies 
> present to even lower frequencies than they actually are. Simulating 
> enhanced base but not of the proper frequency for demodulating into 
> intelligence of course.
> 
> There are a lot of phase shifts going on in an SSB signal just by the 
> nature of the signal.
> 
> I don't know that you will be able to see this stuff on a regular 
> spectrum analyzer. Wonder what you have?
> 
> 73
> Gary  K4FMX
> 
> 
> Joe Isabella wrote:
> > My rig uses DSP generated sidebands.  It would be very difficult to create the kind of
> situation
> > you suggest.  But as you have audio content closer to the carrier point, the receiving station
> > percieves it as a carrier while tuning through because of relative closeness of this content
> to
> > it.
> > 
> > However, I will take a closer look at my transmitted signal and see what it's doing on the
> spec
> > any...
> > 
> > Joe,
> > N3JI
> > 
> > --- Gary Schafer <garyschafer at comcast.net> wrote:
> > 
> > 
> >>The "carrier" that you hear on these signals is probably not carrier but 
> >>inband IM products from the low frequency audio signals. Listen closely 
> >>and you will see that it is only present with modulation.
> >>
> >>As to opposite side band suppression, with a filter, the low frequencies 
> >>are not attenuated by the filter as much as the higher frequencies. 
> >>Because they are closer to the pass band of the filter. Not as far down 
> >>the skirt. So more get through on the unwanted side band. Especially 
> >>when the base is boosted.
> >>
> >>With a phasing type of side band generation the problem comes from 
> >>inadequate phase linearity at the low frequencies. Then add in the 
> >>inband (audio) IM products and the apparent side band suppression really 
> >>gets bad.
> >>
> >>No I am not an advocate of limited bandwidth either. Experimentation is 
> >>great. There are more "better" sounding stations on the air as a result 
> >>of the experimentation. It has a ways to go as far as being "clean" but 
> >>it is no worse sounding than some of those awful appliances with 
> >>"special" microphones designed to "cut through the qrm". They can make 
> >>your ears bleed.
> >>
> >>73
> >>Gary  K4FMX
> >>
> >>
> >>Rob Atkinson, K5UJ wrote:
> >>
> >>>Not at all.  Why?  A.  the > 3 khz guys are almost all using digital 
> >>>phase cancellation methods for sideband generation therefore there is no 
> >>>carrier and no opposite sideband to suppress.
> >>>B.  The few who are using 6 khz xtal filters (actually a little 
> >>>less--5.8 khz) and analog method are using rigs with front panel 
> >>>adjustable microprocessor controlled carrier set points that allow them 
> >>>to place the carrier at least 200 hz below the -6 db filter skirt point 
> >>>so it is way way down the skirt; the opp. s.b. even farther away.  Oh 
> >>>sure, there may be a few hams who are attempting this with the wrong 
> >>>gear and don't know any better.  Anything's possible.    Are mistakes, 
> >>>booboos and a learning curve now forbidden?  I guess it's time for all 
> >>>rigs to be contained in solid epoxy blocks before being sold to us.  
> >>>Didn't know experimentation was taboo.
> >>>
> >>>Rob/K5UJ
> >>>
> >>><<<Having bass that extends well below 100hz will cause a SSB signal to 
> >>>be wide by  modulating too close to the carrier point, crossing over 
> >>>onto the other sideband, and virtually turning into a DSB signal  If you 
> >>>don't believe this just try tuning a "hi-fi" guy in on using the AM 
> >>>mode.  The signal will be 100% intelligible!!  You can even hear the 
> >>>carrier when you tune across one of these signals.  Plus the fact when 
> >>>one tries to force over 10db of extra energy at very low or very high 
> >>>frequencies the IMD is terrific and that also contributes to the width 
> >>>of the signal.
> >>>
> >>>WY3D>>>
> >>>
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> >>
> >>
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> > 
> > 
> > 
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