Whatever the genesis of the LSB/USB convention on the ham bands, this
conversion scheme wasn't it. Mixing a 9 MHz USB signal with a 5 MHz VFO will
produce a USB output on either 4 MHz or 14 Mhz. The sidebands only get
inverted in a mixer when you subtract the SSB signal from a higher frequency
LO.
On 11/22/2011 4:04 PM, KU4AF wrote:
Whatever the genesis of the LSB/USB convention on the ham bands,
this conversion scheme wasn't it. Mixing a 9 MHz USB signal with a 5
MHz VFO will produce a USB output on either 4 MHz or 14 Mhz. The
sidebands only get inverted in a mixer when you subtract
First, let's dispense with the red herring of backward tuning. The VFO does
tune backward on 75 but it has nothing to do with sideband inversion. The
USB/LSB business works the same way with a fixed LO as with a VFO, and it
works as I described.
When you mix a 5 MHz signal with a 9 MHz signal,
Working the sideband part into it with a 9 MHz USB signal and a 5 MHz
LO - Suppressed carrier freq: 9.000 minus 5.000 = 4.000 3 kHz
modulation tone: 9.003 minus 5.000 = 4.003
No, it's 5.000 - 9.000 = -4.000 and 5.000 - 9.003 = 3.997
and it's 5.500 - 9.000 = -3.500 and 5.500 - 9.003 = 3.497
No, it's ... 5.000 - 9.003 = 3.997
and it's ... 5.500 - 9.003 = 3.497
Not in any universe with which humans are familiar. :-)
Mike / KK5F
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Really? You're going to hang your hat on 5.000 - 9.003 = 3.997 ?
Just get a calculator and push the buttons. It's -4.003. Every time! Nothing
in the historical record changes this.
John, KU4AF
Pittsboro, NC
Joe Subich, W4TV-4 wrote
Working the sideband part into it with a 9 MHz USB signal
Is this some sort of new math? As I see it, 9.003 minus 5.000 equals 4.003
and 5.000 minus 9.003 equals -4.003.
Bob, N7XY
On Nov 22, 2011, at 3:44 PM, Joe Subich, W4TV wrote:
Working the sideband part into it with a 9 MHz USB signal and a 5 MHz
LO - Suppressed carrier freq: 9.000 minus
...@mailman.qth.net] On Behalf Of Bob Nielsen
Sent: Tuesday, November 22, 2011 7:16 PM
To: Elecraft List
Subject: Re: [Elecraft] LSB on 75 Meters
Is this some sort of new math? As I see it, 9.003 minus 5.000 equals
4.003 and 5.000 minus 9.003 equals -4.003.
Bob, N7XY
On Nov 22, 2011, at 3:44 PM, Joe Subich
On Tue, Nov 22, 2011 at 6:13 PM, KU4AF johnm...@mindspring.com wrote:
...Just get a calculator...
Instead of all this mathematical analysis, let's do this the democratic
way. Let's have a debate with posturing, table-pounding, and handwaving,
and then have a vote on the correct answer.
Folks - End of Thread. Need I say more? :-)
73, Eric
List modreator
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