[Heathkit] More on the SB-10

[Rodger]

Dave made a very important suggestion on the sideband balance.  I have 
my SB-10  "optimized" for LSB and the USB suppression was about 36 db as 
measured on my Tektronix spectrum analyzer when I restored it several 
years ago.  It still sounds fine but I am sure the suppression has 
dropped a bit since then.  The Central Electronics 10 and 20 are the 
same, you can get extremely good suppression on one sideband at the 
expense of the other.  You generally will need to either let the unit 
warm up for awhile before use or readjust the carrier balance pots a few 
times during warm up.  This is an area where Gonset had a good idea with 
their GSB-100 SSB transmitter, it uses a single crystal in a carrier 
notch circuit and thus the carrier balance controls are not as critical 
on it; finding a GSB-100 with an original power transformer is somewhat 
rare however.

Also, VFO drift is going to be a bit less on the lower bands which again 
favors an emphasis on LSB.

Rodger WQ9E

>  Some good ideas abound in the posts.  I especially liked the idea of
> suppressing the other sideband with a good receiver.  I remember that you
> had to compromise to get
> sideband suppression on upper and lower sideband.  If you got good
> suppression on upper (30 db maybe) then lower was poor (10 to 15 DB).  Even
> Heath mentioned striving for a balance and that is 20 to 25DB.
>
> AS to other rigs that were available.  I was a high school then a college
> kid so $90 looked a lot better than say an HT-37 at nearly $400.
>
> I used a D-104 and we added the audio filter.  I got great reports of
> communications quality audio.  The local master builder W5DYJ had a Collins
> S-Line and I always beat him out in Dx pile ups.  And I was using his old
> homebrew exciter as the exciter for the SB-10 (into a 4-400A AB1 amp).
> W5DYJ had a homebrew amp running 700 watts.
>
> I had one SSB snob break in and tell me my other ssb was only 3 S-units
> below my primary sideband.  I reminded him that the other sideband was
> suppressed not eliminated!
>
> I have a SB-10 and full manual on my projects list.  One day HI.
>
> 73 Dave K4JRB
>
>
>
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