[ARC5] Measuring sideband suppression. (Was BC-458 based SSB rig)

[Leslie Smith]

  Hello Mac,
  Fred Johnson (ZL amateur operator) published the design of a phasing
  rig known as 'the tucker-tin'.
  I built one, and the SA amateur society sold 1000 of this 80m
  transmitter (as a kit).

  Now to the point of your "Q".  Fred described an arrangement to
  suppress the unwanted sideband using a diode detector, 'phones and a
  1000Hz tone (sin) generator.
  I've seen others describe the same method.
  In effect you listened for two tones (1000Hz and 2000Hz).  You set the
  RF phasing components to minimize one tone.
  By measuring the relative level of the 1000Hz tone and the 2000Hz tone
  you can know the sideband suppression.

  It's easy to get 30dB unwanted sideband suppression.
  I got 35 dB suppression.
  You'll work hard to get 40dB sideband suppression.  If your PEP is
  100W, a suppression of 40dB is 10,000 down, so 100,000(mW)/10,000
  equals 10mW of unsuppressed sideband.

  If you have an interest, I'll find the article.


  73 de Les Smith
  vk2bcu at operamail.com


On Sun, Nov 17, 2013, at 13:17, Geoff wrote:
> My HS Physics teacher was an old homebrewer ham and he explained a lot
> about 
> the phasing adjustments as he had built a much more complicated phasing
> rig 
> in the late 40's and still used it.
> 
> I had no way of measuring power but a 20M GP on the garage roof did well
> and 
> then I built the classic make your own GG 1625's linear. Meters wiggled
> and 
> I worked people, that was the extent of my linear knowledge back then! If
> I 
> was spattering someone would tell me to back off on the mike gain and Id 
> then leave it alone.
> 
> Next step was a used CE 10B followed by a used 20A followed by a used
> 100V 
> which I still have.
> 
> Carl
> KM1H
> 
> 
> 
> 
> I built mine in 1962.  Got great carrier suppression, but didn't know how
> to 
> get rid of the unwanted sideband.  I also built a VOX unit with relays
> and 
> dual triodes on a 5x7x3 aluminum box. I wish I still had it!
> 
> * * * * * * * * * * *
> * 73 - Mac, K2GKK/5 *
> * (Since 30 Nov 53) *
> * k2gkk at hotmail.com *
> * Oklahoma City, OK *
> * USAF & FAA (Ret.) *
> * * * * * * * * * * *
> 
> 
> 
> > From: geoffrey at jeremy.mv.com
> > To: arc5 at mailman.qth.net
> > Date: Sat, 16 Nov 2013 17:21:54 -0500
> > Subject: [ARC5] W2EWL BC-458 based SSB rig redone in Nov 2013 ER
> >
> > Originally in March 56 QST, I built one in late 56 with the help of
> > published corrections and the authors help.
> >
> > This ER revision looks like it covers some of the short comings but I sure
> > enjoyed it to get my feet wet in SSB.
> >
> > Carl
> 
> 
> 
> 
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