Butch and Pat are correct about that early circuitry.

I may have spoken out of school about the Swan 350 and the NCX3 not 
having selectable upper or lower sideband on the front panel, but 
several of the early rigs did not.

Despite all the hype about HiFi SSB, Enhanced Sideband, or whatever 
those guys want to call it, there wasn't a better sounding sideband 
transmitter made than a properly aligned and adjusted Central 
Electronics 20A. The other Central electronics rigs sounded good, but 
to my ears that one always sounded better than anything else on the 
band *if the phasing was adjusted properly. Otherwise, it could quite 
often sound like something from another planet.

As a point of trivia, Gerald Youngblood, the founder of Flex Radio, is 
from Mississippi. He said during an interview on either This Week in 
Amateur Radio, or Amateur Radio Newsline, that he had the concept for 
the flex radio rolling around in his head for many years, and it 
originated when he was aligning his Central Electronics 20A while 
still in high school.

----- Original Message ----- 
From: "Butch Bussen" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 14, 2010 9:28 AM
Subject: Re: Upper and Lower side band


I'm not sure, it is kind of like which came first the chicken or the 
egg.
  Many early radios were designed in such a way that the 80 and 40 
meter
bands were derived by the difference frequencies between the vfo and
mixer and the 20 15 and ten meter bands used the sum of the vfo plus
oscillator.  Hope that makes sense.  If you remember theory, when you 
mix
frequencies, such as a vfo plus oscillator you get on the output, both
original frequencies plus sum and difference.  In my national ncx 200
which was my first radio, the if as I recall was 5.2020 and the vfo 
was
somewhere around 9 mhz.  Anyhow, when your mixing a signal and one of
them is ssb, if you use the sum, the sideband stays the same, and if 
you
use the difference such as my national did for 80 and 40, you get the
opposite side band.
73
Butch Bussen
wa0vjr
open Node 3148
Las Vegas


On Wed, 13 Oct 2010, Phil Scovell wrote:

> I think I heard once but I can't remember so does anyone know why 
> the =
> various bands are used for upper and lower side band?  Just curious. 
> =
> There's got to be a reason why it is different based upon the band 
> you =
> are using.
>
> Phil.
> K0NX
>
>


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