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Re: [TenTec] Hi Fi SSB

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Hi Fi SSB
From: Robert & Linda McGraw K4TAX <RMcGraw@Blomand.Net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 16 Feb 2006 21:10:24 -0600
List-post: <mailto:tentec@contesting.com>
Yes and one can maximize the fidelity into the realm of violation of the FCC 
regs.  I for one have been in the SSB bandwidth vs. AM bandwidth debate for 
years.  And yes, I run full carrier DSB otherwise Amplitude Modulation at 
1500 watts PEP.  Simply stated, they are two different modes just like SSB 
and CW are two different modes thus two different bandwidths stipulated.

Guaranteed and fact; the definition of SSB is one which is reduced in 
bandwidth for efficient communications.  One will only get a certain amount 
of information through a 2.8 KHz bandwidth, I don't care how you shape it or 
compress it.  Experiment all you wish but be prepared to justify your 
results to the FCC.  And in another persons words, "I can't think of a 
reason that will be acceptable".

The bottom line, take any portion of the audio spectrum, send it through a 
2.8 KHz filter and you have 2.8 KHz of some portion of the audio spectrum. 
Be it 20 Hz to 2820Hz or be it 500 Hz to 3300 Hz or be it 2500 Hz to 5300 Hz 
you still end up with 2.8 KHz of bandwidth.  You pick how you want it to 
sound.  Have you ever wondered why the female voice sounds somewhat 
different on SSB?  It is the content of the voice vs. the section of the 
audio spectrum processed.

The SSB spectrum was developed for the typical male voice which has more low 
frequencies and fewer high frequencies as compared to the typical female 
voice.  I'd expect the ARGO V with its 500 Hz low end response and a bit 
more high end response to sound quite good with the female voice.  On the 
other hand, that's most likely why the concerns of the frequency response 
with the male voice are being expressed.

Now as to experimentation, if one wishes to develop a system that has a S/N 
ratio of better than 70 dB with a distortion of less than 0.01% and an equal 
quality detection system, then this is legal and is very much a natural part 
of the ham radio hobby.  Have at it.

As to enhanced transmit frequency response requiring more bandwidth for SSB, 
don't go there.

Bob, K4TAX

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