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OT: USB and LSB - How we got there

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Ken G Kopp

OT: USB and LSB - How we got there

Here's a URL to a website with lots of information:

http://www.ac6v.com/73.htm#LSB

Or, search "BC-458 command set transmitter" and
"Central Electronics 10A" with your browser.

73!

Ken Kopp - K0PP
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Alan Bloom

Re: OT: USB and LSB - How we got there

It amazes me that there is still so much confusion and misinformation
about something so simple. There are two ways to get 80 meters (3.5-4
MHz) and 20 meters (14-14.5 MHz) using a single VFO and IF:

9 MHz IF, 5-5.5 MHz VFO:

- Sideband direction is the same on both bands
- VFO tuning direction is inverted on 80, non-inverted on 20

5.25 MHz IF, 8.75-9.25 MHz VFO:

- Sideband direction is inverted on 80, non-inverted on 20
- VFO tuning direction is the same on both bands

So the convention about using LSB on the low bands and USB on the high
bands has nothing to do with a 9 MHz IF. It may have to do with using a
5.25 MHz IF and a VFO centered on 9 MHz.

Alan N1AL

On 02/14/2018 12:08 PM, Ken G Kopp wrote:

> Here's a URL to a website with lots of information:
>
> http://www.ac6v.com/73.htm#LSB
>
> Or, search "BC-458 command set transmitter" and
> "Central Electronics 10A" with your browser.
>
> 73!
>
> Ken Kopp - K0PP

Don Wilhelm

Re: OT: USB and LSB - How we got there

In reply to this post by Ken G Kopp

Ken and all,

BUT, that information is incorrect. The sidebands will NOT invert with
a 9 MHz IF and a 5 MHz VFO.

A little simple math should convince you.
Assume a 9.000 MHz IF and a 5.200 MHz VFO and a modulating frequency of
1kHz.

9.000 + 5.200 = 14.200 for the carrier frequency
9.001 + 5.200 = 14.201 for the modulated frequency. That is Upper Sideband.

9.000 - 5.200 = 3.800 for the carrier frequency
9.001 - 5.200 = 3.800 for the modulated frequency - that is also USB.

The early SSB generators (Central Electronics 10A for one) did use a 9
MHz SSB generator frequency, but there was a switch to change sidebands.

If you have a 5 MHz IF with a 9MHz VFO as was used by Hallicrafters, the
sidebands will invert between 75 and 20 meters. Try the addition and
subtraction to convince yourself.

73,
Don W3FPR

On 2/14/2018 3:08 PM, Ken G Kopp wrote:
> Here's a URL to a website with lots of information:
>
> http://www.ac6v.com/73.htm#LSB
>
> Or, search "BC-458 command set transmitter" and
> "Central Electronics 10A" with your browser.
>
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wb6rse1

Re: OT: USB and LSB - How we got there

In reply to this post by Ken G Kopp

GM3SEK, Ian White's posting here in 2008 is much more illuminating.

> https://marc.info/?l=elecraft&m=121161637904298&w=2 <https://marc.info/?l=elecraft&m=121161637904298&w=2>
Steve WB6RSE

On Feb 14, 2018, at 12:08 PM, Ken G Kopp <[hidden email]> wrote:

Here's a URL to a website with lots of information:

http://www.ac6v.com/73.htm#LSB

Or, search "BC-458 command set transmitter" and
"Central Electronics 10A" with your browser.

73!

Ken Kopp - K0PP
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donovanf

Re: OT: USB and LSB - How we got there

Ian's posting is correct.

A popular method of generating SSB in the late 1940s used a 5 MHz
SSB generator mixed with a 9 MHz VFO producing a USB signal at
14 MHz and a LSB signal at 4 MHz.

See "On the Air with Single Sideband" December 1949 QST
page 58 (lower right hand corner).

http://p1k.arrl.org/pubs_archive/29337

73
Frank
W3LPL

----- Original Message -----

From: [hidden email]
To: "Elecraft" <[hidden email]>
Sent: Wednesday, February 14, 2018 11:15:54 PM
Subject: Re: [Elecraft] OT: USB and LSB - How we got there

GM3SEK, Ian White's posting here in 2008 is much more illuminating.

> https://marc.info/?l=elecraft&m=121161637904298&w=2 <https://marc.info/?l=elecraft&m=121161637904298&w=2>
Steve WB6RSE

On Feb 14, 2018, at 12:08 PM, Ken G Kopp <[hidden email]> wrote:

Here's a URL to a website with lots of information:

http://www.ac6v.com/73.htm#LSB

Or, search "BC-458 command set transmitter" and
"Central Electronics 10A" with your browser.

73!

Ken Kopp - K0PP
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gm3sek

Re: OT: USB and LSB - How we got there

In reply to this post by Alan Bloom

In 2003 I researched the subject for my RSGB Q&A column, 'In
Practice', and was fortunate to be in contact with some amateurs who
were personally involved in the decision to switch sidebands at
10MHz. This decision was made in April 1952 and eventually became an
IARU standard - but its origins are surprisingly technical. The
standard came out of two totally unrelated design decisions, made by
different people on different continents, and at different times in
the late 1940s.

Those post-war years saw a rapid development in intercontinental HF
telephone links. These links used independent-sideband (ISB)
modulation to carry two separate voice channels on opposite
sidebands, and a major manufacturer of ISB equipment at this time
was the Marconi company. The ISB signal was created by up-converting
two separately generated USB and LSB voice channels to the same
suppressed carrier frequency, and the Marconi engineers made the
smart decision to generate the ISB signal on 10.000MHz (a frequency
on which they would never need to transmit, because it was already
occupied by beacons such as WWV).

For transmitted frequencies above 10MHz, Marconi used a
crystal-controlled LO that was 10MHz below the output frequency; so
the IF frequency was added to the LO and the two independent
sidebands remained "the right way up". But for transmitted
frequencies *below* 10MHz, the LO frequency was 10MHz *above* the
output frequency; so the IF frequency was *subtracted* from the LO
and the opposite sidebands were *inverted*. In an ISB system, that
meant that the two telephone channels might very easily become
swapped, so station engineers all around the world needed to be sure
when to flip the appropriate switches.

Out of these working arrangements between engineers, a worldwide
CCIR standard emerged that 10MHz would be the frequency where the
sidebands in ISB systems changed over.

So what has this to do with amateur SSB? Amateur development in the
late 1940s quickly followed the developments in commercial world -
and sometimes involved the same individuals. A major influence was
the W1DX SSB exciter, published in 1949, which automatically
produced a sideband inversion between 80m and 20m. The W1DX design
used the phasing method which allowed easy sideband selection by
flipping a switch at AF, but by the early 1950s there were also many
filter-method exciters that were not so agile.

By 1951-52, experimenters in Europe and the USA were beginning to
talk to each other on 20m, and quickly realised that they were
heading for a mess. Most people were using USB on 20m, but there was
no international agreement on 80m... and what about the other bands?
From eyewitness accounts, April 1952 was the moment when the
agreement crystallized as we know it today.

The two key points in this history are: amateurs were *already
aware* of the commercial dividing line at 10MHz; and the popular
W1DX exciter was *already compatible* with the new proposed standard
[1].

And so it was that two entirely separate and obscure design
decisions - by Marconi engineers and by W1DX - came together to
create the standard that we have today.

[1] SSB exciters using 9MHz SSB generation and a 5MHz VFO are not
relevant to this history. They all came *after* the 10MHz standard
was already in place.

73 from Ian GM3SEK

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gm3sek

Re: OT: USB and LSB - How we got there

Clarification:

W2KUJ first published the design concept for a 20/80m SSB exciter
using 5MHz SSB generation and a 9MHz VFO, in QST for June 1948.

W1DX then expanded W2KUJ's block-diagram concept into a practical
design for others to copy, and this was published in January 1949.

73 from Ian GM3SEK

>-----Original Message-----
>From: [hidden email] [mailto:elecraft-
>[hidden email]] On Behalf Of Ian White
>Sent: 15 February 2018 10:11
>To: 'Alan'; [hidden email]
>Subject: Re: [Elecraft] OT: USB and LSB - How we got there
>
>
>In 2003 I researched the subject for my RSGB Q&A column, 'In
>Practice', and was fortunate to be in contact with some amateurs

who
>were personally involved in the decision to switch sidebands at
>10MHz. This decision was made in April 1952 and eventually became
>an
>IARU standard - but its origins are surprisingly technical. The
>standard came out of two totally unrelated design decisions, made
by

>different people on different continents, and at different times in
>the late 1940s.
>
>Those post-war years saw a rapid development in intercontinental HF
>telephone links. These links used independent-sideband (ISB)
>modulation to carry two separate voice channels on opposite
>sidebands, and a major manufacturer of ISB equipment at this time
>was the Marconi company. The ISB signal was created by up-
>converting
>two separately generated USB and LSB voice channels to the same
>suppressed carrier frequency, and the Marconi engineers made the
>smart decision to generate the ISB signal on 10.000MHz (a frequency
>on which they would never need to transmit, because it was already
>occupied by beacons such as WWV).
>
>For transmitted frequencies above 10MHz, Marconi used a
>crystal-controlled LO that was 10MHz below the output frequency; so
>the IF frequency was added to the LO and the two independent
>sidebands remained "the right way up". But for transmitted
>frequencies *below* 10MHz, the LO frequency was 10MHz *above*
>the
>output frequency; so the IF frequency was *subtracted* from the LO
>and the opposite sidebands were *inverted*. In an ISB system, that
>meant that the two telephone channels might very easily become
>swapped, so station engineers all around the world needed to be

sure

>when to flip the appropriate switches.
>
>Out of these working arrangements between engineers, a worldwide
>CCIR standard emerged that 10MHz would be the frequency where the
>sidebands in ISB systems changed over.
>
>So what has this to do with amateur SSB? Amateur development in the
>late 1940s quickly followed the developments in commercial world -
>and sometimes involved the same individuals. A major influence was
>the W1DX SSB exciter, published in 1949, which automatically
>produced a sideband inversion between 80m and 20m. The W1DX
>design
>used the phasing method which allowed easy sideband selection by
>flipping a switch at AF, but by the early 1950s there were also

many

>filter-method exciters that were not so agile.
>
>By 1951-52, experimenters in Europe and the USA were beginning to
>talk to each other on 20m, and quickly realised that they were
>heading for a mess. Most people were using USB on 20m, but there
>was
>no international agreement on 80m... and what about the other
>bands?
>>From eyewitness accounts, April 1952 was the moment when the
>agreement crystallized as we know it today.
>
>The two key points in this history are: amateurs were *already
>aware* of the commercial dividing line at 10MHz; and the popular
>W1DX exciter was *already compatible* with the new proposed
>standard
>[1].
>
>And so it was that two entirely separate and obscure design
>decisions - by Marconi engineers and by W1DX - came together to
>create the standard that we have today.
>
>
>[1] SSB exciters using 9MHz SSB generation and a 5MHz VFO are not
>relevant to this history. They all came *after* the 10MHz standard
>was already in place.
>
>73 from Ian GM3SEK
>

donovanf

Re: OT: USB and LSB - How we got there

Thanks Ian, very interesting reading!

http://p1k.arrl.org/pubs_archive/28966

73
Frank
W3LPL

----- Original Message -----

From: "Ian White" <[hidden email]>
To: [hidden email]
Sent: Thursday, February 15, 2018 11:27:15 AM
Subject: Re: [Elecraft] OT: USB and LSB - How we got there

Clarification:

W2KUJ first published the design concept for a 20/80m SSB exciter
using 5MHz SSB generation and a 9MHz VFO, in QST for June 1948.

W1DX then expanded W2KUJ's block-diagram concept into a practical
design for others to copy, and this was published in January 1949.

73 from Ian GM3SEK

sure

many

donovanf

Re: OT: USB and LSB - How we got there

The 5.2 MHz SSB exciter construction article that Ian referred to

in January 1949 QST is here:

http://p1k.arrl.org/pubs_archive/29327

73
Frank
W3LPL

----- Original Message -----

From: [hidden email]
To: [hidden email]
Sent: Thursday, February 15, 2018 5:17:57 PM
Subject: Re: [Elecraft] OT: USB and LSB - How we got there

Thanks Ian, very interesting reading!

http://p1k.arrl.org/pubs_archive/28966

73
Frank
W3LPL

----- Original Message -----

From: "Ian White" <[hidden email]>
To: [hidden email]
Sent: Thursday, February 15, 2018 11:27:15 AM
Subject: Re: [Elecraft] OT: USB and LSB - How we got there

Clarification:

W2KUJ first published the design concept for a 20/80m SSB exciter
using 5MHz SSB generation and a 9MHz VFO, in QST for June 1948.

W1DX then expanded W2KUJ's block-diagram concept into a practical
design for others to copy, and this was published in January 1949.

73 from Ian GM3SEK

sure

many

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Mike Harris-9

Re: OT: USB and LSB - How we got there

Members only.

Regards,

Mike VP8NO

On 15/02/2018 14:37, [hidden email] wrote:

> The 5.2 MHz SSB exciter construction article that Ian referred to
>
> in January 1949 QST is here:
>
>
>
> http://p1k.arrl.org/pubs_archive/29327
>
>
> 73
> Frank
> W3LPL

>
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k6dgw

Re: OT: USB and LSB - How we got there

In reply to this post by gm3sek

I have a vague recollection from the early 50s [all recollections from
then are vague] that sideband generation at 5 MHz became popular as
phasing rigs began to give way to filter rigs and for some reason,
crystals in the 5 MHz region were more plentiful and cheaper. ??? The
"9 and 5" scheme gave you 20 and 80 [and I'm not sure when phone on 40
was authorized in the US], but rigs such as the Swan 500 in the early
60's generated SSB at 5.500 MHz with additional VFO frequencies to hit
40, 15, and 10 as well.

I was originally licensed in '53 but had been listening since mid '51
and the "LSB below 10 Mcs, USB above" convention was thoroughly and
firmly established by then. Nice to know where it came from.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 2/15/2018 3:27 AM, Ian White wrote:

> Clarification:
>
> W2KUJ first published the design concept for a 20/80m SSB exciter
> using 5MHz SSB generation and a 9MHz VFO, in QST for June 1948.
>
> W1DX then expanded W2KUJ's block-diagram concept into a practical
> design for others to copy, and this was published in January 1949.
>
> 73 from Ian GM3SEK
>
>> -----Original Message-----
>> From: [hidden email] [mailto:elecraft-
>> [hidden email]] On Behalf Of Ian White
>> Sent: 15 February 2018 10:11
>> To: 'Alan'; [hidden email]
>> Subject: Re: [Elecraft] OT: USB and LSB - How we got there
>>
>>
>> In 2003 I researched the subject for my RSGB Q&A column, 'In
>> Practice', and was fortunate to be in contact with some amateurs
> who
>> were personally involved in the decision to switch sidebands at
>> 10MHz. This decision was made in April 1952 and eventually became
>> an
>> IARU standard - but its origins are surprisingly technical. The
>> standard came out of two totally unrelated design decisions, made
> by
>> different people on different continents, and at different times in
>> the late 1940s.
>>
>> Those post-war years saw a rapid development in intercontinental HF
>> telephone links. These links used independent-sideband (ISB)
>> modulation to carry two separate voice channels on opposite
>> sidebands, and a major manufacturer of ISB equipment at this time
>> was the Marconi company. The ISB signal was created by up-
>> converting
>> two separately generated USB and LSB voice channels to the same
>> suppressed carrier frequency, and the Marconi engineers made the
>> smart decision to generate the ISB signal on 10.000MHz (a frequency
>> on which they would never need to transmit, because it was already
>> occupied by beacons such as WWV).
>>
>> For transmitted frequencies above 10MHz, Marconi used a
>> crystal-controlled LO that was 10MHz below the output frequency; so
>> the IF frequency was added to the LO and the two independent
>> sidebands remained "the right way up". But for transmitted
>> frequencies *below* 10MHz, the LO frequency was 10MHz *above*
>> the
>> output frequency; so the IF frequency was *subtracted* from the LO
>> and the opposite sidebands were *inverted*. In an ISB system, that
>> meant that the two telephone channels might very easily become
>> swapped, so station engineers all around the world needed to be
> sure
>> when to flip the appropriate switches.
>>
>> Out of these working arrangements between engineers, a worldwide
>> CCIR standard emerged that 10MHz would be the frequency where the
>> sidebands in ISB systems changed over.
>>
>> So what has this to do with amateur SSB? Amateur development in the
>> late 1940s quickly followed the developments in commercial world -
>> and sometimes involved the same individuals. A major influence was
>> the W1DX SSB exciter, published in 1949, which automatically
>> produced a sideband inversion between 80m and 20m. The W1DX
>> design
>> used the phasing method which allowed easy sideband selection by
>> flipping a switch at AF, but by the early 1950s there were also
> many
>> filter-method exciters that were not so agile.
>>
>> By 1951-52, experimenters in Europe and the USA were beginning to
>> talk to each other on 20m, and quickly realised that they were
>> heading for a mess. Most people were using USB on 20m, but there
>> was
>> no international agreement on 80m... and what about the other
>> bands?
>> >From eyewitness accounts, April 1952 was the moment when the
>> agreement crystallized as we know it today.
>>
>> The two key points in this history are: amateurs were *already
>> aware* of the commercial dividing line at 10MHz; and the popular
>> W1DX exciter was *already compatible* with the new proposed
>> standard
>> [1].
>>
>> And so it was that two entirely separate and obscure design
>> decisions - by Marconi engineers and by W1DX - came together to
>> create the standard that we have today.
>>
>>
>> [1] SSB exciters using 9MHz SSB generation and a 5MHz VFO are not
>> relevant to this history. They all came *after* the 10MHz standard
>> was already in place.
>>
>> 73 from Ian GM3SEK
>>
> ______________________________________________________________
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