Re: [Elecraft] LSB on 75 Meters [END of thread.]
Folks - End of Thread. Need I say more? :-) 73, Eric List modreator --- www.elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
On Tue, Nov 22, 2011 at 6:13 PM, KU4AF 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. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
I think that this is a waste of energy, and a bit pissy. I am going to stretch out on the couch, pour a glass of good CA Cab, and listen to the rain on the tin roof. 73 ya 'll w6izt/4 (sorry eric) -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@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, 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 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 > > The VFO does not need to be the LO ... the IF can just as easily be > connected to the LO port. > >> Just as a sanity check, take another look at your own negative >> number example, Joe, and 'splain to me how 5.000 minus 9.003 gives >> minus 3.987. OK,I'll grant you a typo and assume you meant minus >> 3.997, but you're still wrong. It's minus 4.003. > > You're correct it's a typo *BUT* there is no error in the inversion > when the 9 MHz USB signal is applied to the LO port of the mixer. > All you need to do is spend some time with the historical record. > > 73, > >... Joe, W4TV > > > On 11/22/2011 6:22 PM, KU4AF wrote: >> 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, there's no need to stand on >> your head and pretend that you're subtracting 9 from 5 to get minus 4. >> Instead, you go back to second grade and subtract 5 from 9 and get 4. >> >> 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 >> >> Just as a sanity check, take another look at your own negative number >> example, Joe, and 'splain to me how 5.000 minus 9.003 gives minus 3.987. OK, >> I'll grant you a typo and assume you meant minus 3.997, but you're still >> wrong. It's minus 4.003. >> >> John, KU4AF >> Pittsboro, NC >> >> >> 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 the SSB >>> signal from a higher frequency >> >> Try the math again ... >> >> If you have a 5.0 - 5.5 MHz VFO and subtract a 9 MHz USB signal from >> that VFO you end up with a LSB output that tunes from 4.0 - 3.5 MHz >> in reverse. Start at 5.0 and subtract the 9 MHz carrier frequency you >> get *minus* 4.0 MHz (carrier frequency) when the highest modulating >> frequency (3 KHz or 9.003 MHz) is used you end up with *minus* 3.987 >> MHz - *lower sideband*! Do the same with the VFO at 5.5 MHz and you >> will find LSB at *minus* 3.497 to 3.500 MHz. >> >> A mixer can produce F2 +/- F1 just as easily as it produces outputs >> at F1 +/- F2. If you don't believe this ... spend some time reviewing >> the early SSB transmitter and receiver articles in QST from the 1950s >> or borrow a Drake 1A/2A/2B and learn why some bands "tune backward." >> >> 73, >> >> ... Joe, W4TV >> >> >> -- >> View this message in context: http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FC C-tp7011949p7022509.html >> Sent from the Elecraft mailing list archive at Nabble.com. >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > __ > Elecraft mailing list
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, 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 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 > > The VFO does not need to be the LO ... the IF can just as easily be > connected to the LO port. > >> Just as a sanity check, take another look at your own negative >> number example, Joe, and 'splain to me how 5.000 minus 9.003 gives >> minus 3.987. OK,I'll grant you a typo and assume you meant minus >> 3.997, but you're still wrong. It's minus 4.003. > > You're correct it's a typo *BUT* there is no error in the inversion > when the 9 MHz USB signal is applied to the LO port of the mixer. > All you need to do is spend some time with the historical record. > > 73, > >... Joe, W4TV > > > On 11/22/2011 6:22 PM, KU4AF wrote: >> 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, there's no need to stand on >> your head and pretend that you're subtracting 9 from 5 to get minus 4. >> Instead, you go back to second grade and subtract 5 from 9 and get 4. >> >> 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 >> >> Just as a sanity check, take another look at your own negative number >> example, Joe, and 'splain to me how 5.000 minus 9.003 gives minus 3.987. OK, >> I'll grant you a typo and assume you meant minus 3.997, but you're still >> wrong. It's minus 4.003. >> >> John, KU4AF >> Pittsboro, NC >> >> >> 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 the SSB >>> signal from a higher frequency >> >> Try the math again ... >> >> If you have a 5.0 - 5.5 MHz VFO and subtract a 9 MHz USB signal from >> that VFO you end up with a LSB output that tunes from 4.0 - 3.5 MHz >> in reverse. Start at 5.0 and subtract the 9 MHz carrier frequency you >> get *minus* 4.0 MHz (carrier frequency) when the highest modulating >> frequency (3 KHz or 9.003 MHz) is used you end up with *minus* 3.987 >> MHz - *lower sideband*! Do the same with the VFO at 5.5 MHz and you >> will find LSB at *minus* 3.497 to 3.500 MHz. >> >> A mixer can produce F2 +/- F1 just as easily as it produces outputs >> at F1 +/- F2. If you don't believe this ... spend some time reviewing >> the early SSB transmitter and receiver articles in QST from the 1950s >> or borrow a Drake 1A/2A/2B and learn why some bands "tune backward." >> >> 73, >> >> ... Joe, W4TV >> >> >> -- >> View this message in context: >> http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7022509.html >> Sent from the Elecraft mailing list archive at Nabble.com. >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html _ N7XY DX Cluster Node - telnet to n7xy.net, port 7300 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
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 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 > > The VFO does not need to be the LO ... the IF can just as easily be > connected to the LO port. > >> Just as a sanity check, take another look at your own negative >> number example, Joe, and 'splain to me how 5.000 minus 9.003 gives >> minus 3.987. OK,I'll grant you a typo and assume you meant minus >> 3.997, but you're still wrong. It's minus 4.003. > > You're correct it's a typo *BUT* there is no error in the inversion > when the 9 MHz USB signal is applied to the LO port of the mixer. > All you need to do is spend some time with the historical record. > > 73, > > ... Joe, W4TV > > -- View this message in context: http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7022614.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
>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 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
> 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 The VFO does not need to be the LO ... the IF can just as easily be connected to the LO port. > Just as a sanity check, take another look at your own negative > number example, Joe, and 'splain to me how 5.000 minus 9.003 gives > minus 3.987. OK,I'll grant you a typo and assume you meant minus > 3.997, but you're still wrong. It's minus 4.003. You're correct it's a typo *BUT* there is no error in the inversion when the 9 MHz USB signal is applied to the LO port of the mixer. All you need to do is spend some time with the historical record. 73, ... Joe, W4TV On 11/22/2011 6:22 PM, KU4AF wrote: > 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, there's no need to stand on > your head and pretend that you're subtracting 9 from 5 to get minus 4. > Instead, you go back to second grade and subtract 5 from 9 and get 4. > > 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 > > Just as a sanity check, take another look at your own negative number > example, Joe, and 'splain to me how 5.000 minus 9.003 gives minus 3.987. OK, > I'll grant you a typo and assume you meant minus 3.997, but you're still > wrong. It's minus 4.003. > > John, KU4AF > Pittsboro, NC > > > 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 the SSB >> signal from a higher frequency > > Try the math again ... > > If you have a 5.0 - 5.5 MHz VFO and subtract a 9 MHz USB signal from > that VFO you end up with a LSB output that tunes from 4.0 - 3.5 MHz > in reverse. Start at 5.0 and subtract the 9 MHz carrier frequency you > get *minus* 4.0 MHz (carrier frequency) when the highest modulating > frequency (3 KHz or 9.003 MHz) is used you end up with *minus* 3.987 > MHz - *lower sideband*! Do the same with the VFO at 5.5 MHz and you > will find LSB at *minus* 3.497 to 3.500 MHz. > > A mixer can produce F2 +/- F1 just as easily as it produces outputs > at F1 +/- F2. If you don't believe this ... spend some time reviewing > the early SSB transmitter and receiver articles in QST from the 1950s > or borrow a Drake 1A/2A/2B and learn why some bands "tune backward." > > 73, > > ... Joe, W4TV > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7022509.html > Sent from the Elecraft mailing list archive at Nabble.com. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
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, there's no need to stand on your head and pretend that you're subtracting 9 from 5 to get minus 4. Instead, you go back to second grade and subtract 5 from 9 and get 4. 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 Just as a sanity check, take another look at your own negative number example, Joe, and 'splain to me how 5.000 minus 9.003 gives minus 3.987. OK, I'll grant you a typo and assume you meant minus 3.997, but you're still wrong. It's minus 4.003. John, KU4AF Pittsboro, NC 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 the SSB > signal from a higher frequency Try the math again ... If you have a 5.0 - 5.5 MHz VFO and subtract a 9 MHz USB signal from that VFO you end up with a LSB output that tunes from 4.0 - 3.5 MHz in reverse. Start at 5.0 and subtract the 9 MHz carrier frequency you get *minus* 4.0 MHz (carrier frequency) when the highest modulating frequency (3 KHz or 9.003 MHz) is used you end up with *minus* 3.987 MHz - *lower sideband*! Do the same with the VFO at 5.5 MHz and you will find LSB at *minus* 3.497 to 3.500 MHz. A mixer can produce F2 +/- F1 just as easily as it produces outputs at F1 +/- F2. If you don't believe this ... spend some time reviewing the early SSB transmitter and receiver articles in QST from the 1950s or borrow a Drake 1A/2A/2B and learn why some bands "tune backward." 73, ... Joe, W4TV -- View this message in context: http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7022509.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters
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 the SSB > signal from a higher frequency Try the math again ... If you have a 5.0 - 5.5 MHz VFO and subtract a 9 MHz USB signal from that VFO you end up with a LSB output that tunes from 4.0 - 3.5 MHz in reverse. Start at 5.0 and subtract the 9 MHz carrier frequency you get *minus* 4.0 MHz (carrier frequency) when the highest modulating frequency (3 KHz or 9.003 MHz) is used you end up with *minus* 3.987 MHz - *lower sideband*! Do the same with the VFO at 5.5 MHz and you will find LSB at *minus* 3.497 to 3.500 MHz. A mixer can produce F2 +/- F1 just as easily as it produces outputs at F1 +/- F2. If you don't believe this ... spend some time reviewing the early SSB transmitter and receiver articles in QST from the 1950s or borrow a Drake 1A/2A/2B and learn why some bands "tune backward." 73, ... Joe, W4TV 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 the SSB signal from a higher frequency > LO. > > This "ham legend" has persisted literally for generations despite frequent > debunking. Maybe we can eradicate it by teaching our grandkids that "We had > to use LSB back then because DSP hadn't been invented yet." > > John, KU4AF > Pittsboro, NC > > > w5tvw wrote >> >> >> The reason this was done was due to the conversion process employed as >> the >> SSB signal was generated at 9 Mhz and heterodyned to either 14, or 4 Mhz >> with a 5 MHz VFO signal. Whichever position of the mode switch was used >> (SB1 in all probability, it's been too many years for me to precisely >> recall >> and not really important at this time for me to research it!) At any >> rate, >> the result was Upper sideband signals on 14 Mhz and lower sideband signals >> at 3.8-4.0 Mhz. >> > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7021971.html > Sent from the Elecraft mailing list archive at Nabble.com. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] LSB on 75 Meters (was: US 60 Meter Band Changes...)
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. This "ham legend" has persisted literally for generations despite frequent debunking. Maybe we can eradicate it by teaching our grandkids that "We had to use LSB back then because DSP hadn't been invented yet." John, KU4AF Pittsboro, NC w5tvw wrote > > > The reason this was done was due to the conversion process employed as > the > SSB signal was generated at 9 Mhz and heterodyned to either 14, or 4 Mhz > with a 5 MHz VFO signal. Whichever position of the mode switch was used > (SB1 in all probability, it's been too many years for me to precisely > recall > and not really important at this time for me to research it!) At any > rate, > the result was Upper sideband signals on 14 Mhz and lower sideband signals > at 3.8-4.0 Mhz. > -- View this message in context: http://elecraft.365791.n2.nabble.com/US-60-Meter-Band-Changes-Approved-by-FCC-tp7011949p7021971.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
