[Boatanchors] SSB Generation - Phasing VS Filter Opinion Sought

[D C _Mac_ Macdonald]

Now, I sorta wish I had that old W2EWL rig back.  I might even get the unwanted sideband suppressed!  I did have super carrier suppression, and had lots of QSOs with SSB stations, some of whom mistuned my voice enough to detect the weirdness in audio.  I even built a VOX with anti-VOX unit for it on a 5x7x2 Bud box.

I sold the rig to somebody in Texas after I bought my first commercial SSB rig; Hammarlund HX-50 in 1963 or 1964, so the info below was just a little bit too late!

73 de Mac, K2GKK/5​
Since 30 Nov 1953​
Oklahoma City, OK​
USAF, Retired ('61-'81)​
FAA, Retired ('94-'10)


From: Robert Nickels <ranickel at comcast.net>
Sent: Saturday, July 20, 2019 13:04
To: D C _Mac_ Macdonald; W9RAN at oneradio.net
Cc: Whitebear1122; BOATANCHORS2 LIST
Subject: Re: [Boatanchors] SSB Generation - Phasing VS Filter Opinion Sought

On 7/19/2019 5:19 PM, D C _Mac_ Macdonald wrote:
> My 1st SSB rig was the W2EWL rig but I never knew how to align it
to get rid of unwanted sideband.  Only had a cheap VOM!

Equipment manuals and handbooks were filled with complex oscilloscope
screens and discussion of ripple and as a result proper alignment of a
phasing rig eluded most hams.    But a clever New Zealand ham, Fred
Johnson ZL2AMJ was able to see what everyone else had missed, and
published a short note in the NZ ham magazine in 1972 that makes the
process simple and requires only a sine wave audio generator and a
simple output detector:

The principle is simple.  We all know that feeding a single audio tone
into a properly aligned SSB transmitter will produce an unmodulated
carrier output (this is how most filter rigs produce CW).   This is the
desired outcome.

An improperly aligned phasing rig will have both carrier and opposite
sideband imbalance.   If we inject a 1 kHz audio tone and the carrier is
not balanced, the result will be AM - a carrier with a sideband
separated by 1 kHz on either side.   The output detector that is
attached to the transmitter is nothing more than a crystal radio or
field strength meter that will demodulate this signal to allow a 1 kHz
tone to be heard in the headphones (or amplified speaker as I prefer),
no different than an AM transmitter will do.    Step one is to adjust
the carrier null controls to eliminate the 1 kHz tone.    This takes less
time than it does to type this sentence!

With the carrier nulled there will now only be a  2kHz tone audible.
This is the result of the desired sideband beating against the undesired
sideband, which are 2 Khz apart with a 1 kHz tone.    Now the Audio and
RF phasing controls can be adjusted to null the 2 kHz tone.   Switching
between USB and LSB is necessary to reach the best compromise.

That's  it!   Two simple nulling adjustments, no oscilloscope or even a
VOM needed.      And if you don't trust your hearing or wish to have a
visual indication, just download one of the free audio spectrum analyzer
apps for your smartphone or PC and it will display the  1 and 2 kHz
signal peaks in real time.

ZL2AMJ is  known by many as the inventor of the "Tucker Tin Two",  a
minimalist SSB transmitter using just two tubes, and was a leader in NZ
amateur licensing for many years.   He became a Silent Key in 2015 but
in a previous email exchange I asked him how he came up with this clever
method that no one else ever had suggested.  His reply was "it just
seemed obvious to me".   And so it is!

Fred's original description can be found here: https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Ftinyurl.com%2Fy2qjgehr&amp;data=02%7C01%7C%7C527e8078a7fd41bc81a308d70d3cc3f7%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636992426936860055&amp;sdata=0EjxvtDx3cIOC%2FqMQpqUtPtCyKzgNyx0QxPJ0HKRx3A%3D&amp;reserved=0

73, Bob W9RAN

PS:   A simple $50 rtl-sdr will also serve as a "poor man's spectrum
analyzer" to allow direct viewing of HF signals and is a must for any
workbench.