++++++++++++++++++++ See also K2 VCO Freq Calibrate ++++++++++++++++++++ From: "Don Brown" To: "VR2BrettGraham" , "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 07:43:26 -0600 Hi Here is the procedure that is in the instructions for the noise generator= kit I have for sale: It=E2=80=99s not that hard to get everything close to perfect if you will= spend a little time with WWV, Spectrogram and your noise generator. This= is the method I use to align a K2: =20 The first thing is to make sure the K2 is on frequency you can check that= by looking at WWV with Spectrogram looking for the 500 and 600 Hz tones = on alternating minutes (you may need to wait a little, the tones are not = on all minutes of the hour). Use USB or LSB mode. Set up a marker at 500 = and 600 Hertz on the Spectrogram display. When you have the tones on the = spectrogram markers, read the VFO frequency and write it down. Connect th= e frequency probe to TP3 in FCNTR mode and adjust C22 on the control boar= d to change the indicated frequency by the amount needed to make the VFO = correct. Here is an example: if the VFO is reading 20 counts high then ch= ange the frequency at TP3 20 counts lower (note: the frequency at TP3 wil= l be around 12 MHz not the VFO frequency). Move the counter probe to TP1 = and select 40 meters and run CAL PLL. This should put your VFO on frequen= cy. Recheck against WWV and repeat if necessary. =20 Then use Spectrogram and your noise generator to set up your filters. Pre= set them to the settings in the K2 manual first so you are sure you are o= n the right side of the band-pass then adjust the filters with Spectrogra= m to center the band-pass on a marker set at your side-tone frequency. Th= e noise generator connected to the K2 antenna makes it easier to see the = band-pass. You may need to do all of the above more than once to get ever= ything right. When setting up sideband move the band-pass so the lowest p= oint on the skirt on the left starts just a little past 0 Hz. Set each fi= lter trying to duplicate that left hand skirt. You may need to adjust the= K2 volume control for the best display. =20 =20 If you would like to check out your K2 filters here is a quick way to mak= e sure you have it right. Set the band to 80 meters and set the VFO to 40= 00.00 select CW mode and FL1. You should hear the MPU 4.00 MHz clock as a= 600 Hz tone assuming your side tone is set to 600. If not adjust the VFO= a little to zero beat with the spot tone. Now cycle through the filters = FL1-FL4. The frequency should not change at all or very little. Now witho= ut touching the VFO frequency hold the CW REV button to select CW reverse= . Again the tone should not change with the reverse or when cycling throu= gh the filters. =20 Now switch to USB mode and change the VFO to 3999.40 and you should hear = the same note. Cycle through the filters and it should not change. Change= to LSB and set the VFO to 4000.60 and you should hear the same 600 Hz no= te when cycling the filters. If it will do all of the above then you have= got it set as good as it gets. =20 = =20 Don Brown, KD5NDB ----- Original Message ----- From: VR2BrettGraham Sent: Thursday, October 31, 2002 2:18 AM To: elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Thanks to N0SS, KC4KGU, W3FPR & K6SE for their replies. Provided everything is set up right & the signal tuned in properly, =20 toggling between CW & CW reverse modes should result in no or little change in the tone of= the received signal. -- snip -- +++++++++++++++++++++ To: DolfinDon at msn.com, vr2bg at harts.org.hk, elecraft at mailman.qth.net Date: Thu, 31 Oct 2002 12:48:06 -0800 Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO From: k6se at juno.com KD5NDB wrote: "The first thing is to make sure the K2 is on frequency you can check that by looking at WWV with Spectrogram looking for the 500 and 600 Hz tones on alternating minutes (you may need to wait a little, the tones are not on all minutes of the hour). Use USB or LSB mode. Set up a marker at 500 and 600 Hertz on the Spectrogram display. When you have the tones on the spectrogram markers, read the VFO frequency and write it down. Connect the frequency probe to TP3 in FCNTR mode and adjust C22 on the control board to change the indicated frequency by the amount needed to make the VFO correct." ========== Although you can make the VFO frequency readout accurate (ignoring the K2's temperature drift problem), I was told by Elecraft that if C22 on the control board is not adjusted so that the 4.000 MHz oscillator is exactly 4.000000 MHz that the K2's built-in frequency counter will not be accurate, and that it should be adjusted that way and we should accept any VFO frequency readout error which might occur as a result. With the 4.000 MHz oscillator adjusted properly, the BFO frequency readouts will be accurate when setting up the filters (as well as any other frequency measurements done with the built-in frequency counter). In fact, the #1 choice of setting C22 in the K2 manual is to set if for exactly 4000.0000 kHz [and ignore any VFO frequency error]. 73, de Earl, K6SE +++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 16:48:46 -0600 Hi This procedure for setting the 4.000 MHz clock is right out of the Elecra= ft manual page 98 and it does put the 4.000 MHz clock on frequency calibr= ated to WWV. This is a better way to do it because placing a probe on the= 4.000 MHz test point will detune it a little. Even if you have a frequen= cy counter and you adjust the clock by measuring the reference oscillator= per the manual on page 57 it will not be as accurate as the calibration = to WWV on page 98. My procedure is just a slight modification of this met= hod. I have done 8 or 10 K2's this way and it works better than the simpl= er methods in the cal setup on page 57. Don Brown KD5NDB ++++++++++++++++ Date: Thu, 31 Oct 2002 18:31:07 -0500 (EST) From: kc4kgu at ENTERZONE.NET To: Don Brown Cc: Elecraft Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO I kinda used Dons settings today with what appear to be great results. I set all filters to the "defaults" per the K2 + KSB2 manuals. I then went to WWV at 10Mhz. With my sidetone set to 600Hz, I used SPOT in CW mode to zero beat and then verified in LSB that the 600Hz tone that is present every few minutes and the 500Hz tone likewise were indicated at the like markers in Spectrogram. I noted the dial freq error and made adjustment to C22 accordingly. After running CAL PLL and repeating this process a couple of times, I got the K2 back to pretty much dead on frequency at 10Mhz. I then verified that my 10Mhz reference was also dead on (since WWV was starting to fade on me!) which it was. I then hooked the 10Mhz reference up to the K2. I went through and set all of the CW filters watching the spectrogram display and also using SPOT. I repeated for CW-R. While there is a slight tone difference between CW and CW-R, it tracks identical to my TS-2000 so, I'm not concerned. I dialed up 10000.60 on the TS-2000, selected LSB and adjusted all of the LSB filters to put the beat tone right on 600Hz. I then dialed up 9999.40 with USB and did the same. I exited CAL and verified that all modes and filters functioned properly with my 10Mhz reference. I then dialed up 4000.00 and verified that CW + SPOT was zerobeat with the birdy and the I got a 600Hz tone verified with Spectrogram. I repeated with CW-R, USB at 3999.40 and LSB at 10000.60. Everything looked right on Spectrogram so, I hooked the K2 to the dummy load, dialed up 10000.00 LSB on the K2, 10000.00 LSB on the TS-2000 and listened to myself. I sounded like me. A switch to USB produced the same results. TX into the dummy load in CW mode on both rigs produced a 600Hz on the other receiver. TX into the dummy load in CW-R produced a 600Hz tone on the other receiver. So, while my K2 might not be exactly on frequency, it's just as close as my TS-2000 is at 10Mhz now. The last thing I did to test alignment was to dial up one of the local AM broadcast stations. It zero-beat EXACTLY on frequency in CW mode and both USB and LSB sounded nearly indentical to each other. Does anyone see any error in my methodology as described above? 73 de John - KC4KGU K2/100 #2490 ++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Date: Thu, 31 Oct 2002 15:52:54 -0800 Subject: [Elecraft] Setting K2 Frequency Calibration Earl makes an excellent point. The way I set C22 in my K2 that is directly traceable to the National Bureau of Standards was to pick a time when the WWV signal on 20 MHz was audible on my auxiliary receiver. Then I arranged a pickup wire near the K2 so I could hear the 5th harmonic of the 4 MHz oscillator in my aux. receiver as well. It is easy to adjust C22 to put the 4 MHz oscillator frequency within 1/4 Hz of WWV. That is, the 'swish' of the slow beat between WWV and the oscillator signal as heard in the auxiliary receiver was less than one every four seconds. That places the 4.000 MHz oscillator to within 0.05 Hz of 4.0000000 MHz. That's much MUCH closer than the temperature stability of the oscillator will be able to keep it over time, so the accuracy of the K2 is then set entirely by the stability of the oscillator and NOT by my calibration. No "fancy" test equipment required, just a receiver capable of receiving WWV on 20 mHz. That's sometimes a bit of a challenge because WWV runs a much lower power on 20 MHz than it does on the other HF frequencies. It may require a little messing around with the wire pickup for the 4.000 MHz signal from the K2 so it is not too strong or too weak. The "beat" will be strongest when both WWV and the oscillator signal from the K2 are equal in strength. And it is important to be sure that you are zero-beating the carrier frequency of WWV and not one of the sidebands produced by the tone modulation. That's easy to spot during the voice announcement. You should hear the 'swish' of the beat during the voice announcement. If your "beat" goes away when the tone stops, you've zero beated the sideband and not the carrier. Don't forget to run CAL PLL after adjusting C22, and going through CAL FIL and changing each BFO frequency then resetting it to force the system to re-calculate the frequency data stored in memory. Now any errors in the frequency display will be due to the oscillator drift or the tuning algorithm, as Earl points out. Ron AC7AC K2 # 1289 ... the #1 choice of setting C22 in the K2 manual is to set if for exactly 4000.0000 kHz [and ignore any VFO frequency error]. 73, de Earl, K6SE ++++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] Setting K2 Frequency Calibration Date: Thu, 31 Oct 2002 19:08:02 -0600 Hi That sounds like a good method also. Just remember the 4.000 MHz clock is= only required during the CAL PLL routine, so long term stability is not = required. It only needs to be exactly 4.000 MHz for a few minutes while t= he calibration runs. The frequency counter is used to build the look up t= ables in the EEPROM to calibrate the voltage controlled VFO. Once this is= done the counter is not even connected to the VFO. You can improve the accuracy and cut the drift in half by removing X2 in = the reference oscillator. As long as you can get a 10 KHz shift in the re= ference oscillator as described on page 57, one crystal will work better.= If you can not get enough range swap the crystals or order a new set (Er= ic told me all of the newer crystals have enough range so this should not= be a problem). This works because each step of the D to A converter chan= ges the reference frequency a smaller amount with only one crystal and on= e crystal is more temperature stable so you get a double benefit. I have = done this on several K2's and it really makes a difference. You need to r= e-run the CAL PLL after you remove the crystal or if you change crystals = and of course the 4.000 Mhz oscillator needs to be right on for the calib= ration using your favorite method. :-) Don Brown KD5NDB ----- Original Message ----- From: Ron D'Eau Claire Sent: Thursday, October 31, 2002 6:00 PM To: elecraft at mailman.qth.net Subject: [Elecraft] Setting K2 Frequency Calibration Earl makes an excellent point. The way I set C22 in my K2 that is directly traceable to the National Bureau of Standards was to pick a time when the WWV signal on 20 MHz was audible on my auxiliary receiver. Then I arranged a pickup wire near the K2 so I could hear the 5th harmonic of the 4 MHz oscillator in my aux. receiver as well. It is easy to adjust C22 to put the 4 MHz oscillator frequency within 1/4 Hz of WWV. That is, the 'swish' of the slow beat between WWV and the oscillator signal as heard in the auxiliary receiver was less than one every four seconds. That places the 4.000 MHz oscillator to within 0.05 Hz of 4.0000000 MHz. That's much MUCH closer than the temperature stability of the oscillator will be able to keep it over time, so the accuracy of the K2 is then set entirely by the stability of the oscillator and NOT by my calibration. -- snip -- ++++++++++++++++ To: kc4kgu at ENTERZONE.NET, elecraft at mailman.qth.net Date: Thu, 31 Oct 2002 17:56:42 -0800 Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO From: k6se at juno.com KC4KGU wrote: "I then dialed up 4000.00 and verified that CW + SPOT was zerobeat with the birdy and the I got a 600Hz tone verified with Spectrogram. I repeated with CW-R, USB at 3999.40 and LSB at 10000.60..... ...Does anyone see any error in my methodology as described above?" ========== First, I think you meant "LSB at 4000.60" above. Actually CW and CWR are "USB" and "LSB" respectively (depending on the band the K2 is on), so when you refer to "CWR" in terms of both USB and LSB it doesn't make sense. I may be wrong, but it sounds like you are adjusting the CW filters offset by 600 Hz (your pitch preference) from the correct frequency. An unmodulated carrier on exactly 4000.000 kHz should be heard with a pitch of 600 Hz when your K2 is tuned to exactly 4000.000 kHz (not to 4000.600 or 3999.400). If your K2's VFO readout is accurate, it should read "4.000.00" when that received signal's pitch is 600 Hz, no matter whether your receiver is on CW or CWR. 73. de Earl, K6SE ++++++++++++++++ To: elecraft at mailman.qth.net Date: Thu, 31 Oct 2002 18:13:16 -0800 Subject: Re: [Elecraft] Setting K2 Frequency Calibration From: k6se at juno.com Ron, AC7AC's method of using 20 MHz WWV to zero the 5th harmonic of the K2's 4 MHz oscilator is an outstanding suggestion. This way, the radio used to receive WWV does not require VFO accuracy like a radio needs for listening at 4000.000 kHz -- just tune the radio to 20 MHz WWV's carrier. That makes the accuracy of adjusting the K2's 4 MHz oscillator at least 5 times more accurate. Kudos to Ron! 73, de Earl, K6SE +++++++++++++++++ From: "Don Brown" To: , , "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 20:20:25 -0600 The setting of 4000.600 and 3999.400 settings check out the USB and LSB n= ot CW. When checking CW and CWR you tune 4000.000 and the tone is 600 Hz = if your side tone is 600 Hz. When you go to sideband there is not an offs= et so you need to dial in the +/-600 offset to hear the same 600 HZ tone Don Brown KD5NDB ++++++++++++++++ From: "Don Brown" To: , "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 20:38:39 -0600 Hi The only reason you need to set the 4.000 Mhz oscillator is so the firmwa= re can set the VFO look up tables to make the dial read correctly. The 4 = Mhz oscillator is not used for anything except running the MPU at any oth= er time and could be set anywhere and it would not matter to the operatio= n of the K2 or the calibration. The only time it needs to be accurate is = when CAL PLL is running. As the Frequency counter is only used to set the= CAL PLL and the filters during setup it only makes sense to set it so th= e VFO is the most accurate it can be and if that is exactly 4.000000 then= so be it, but if it needs to be a few hertz one side or the other to mak= e CAL PLL set the VFO right then that's where I will set it. The procedur= e that I use or the one using another receiver are the only ones that do = this. A frequency counter is only as accurate as it's internal time base = but even if it is right on it may not set the VFO to the best place. I ha= ve seen several K2 setup with a frequency counter that I was able to impr= ove with my method. Don Brown KD5NDB +++++++++++++++ Date: Thu, 31 Oct 2002 19:19:32 -0800 From: Vic Rosenthal Organization: Transparent Software To: Don Brown Cc: Elecraft Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Don Brown wrote: > > The only time it needs to be accurate is when CAL PLL is running. This implies that I could do the whole process of setting the 4 MHz oscillator and doing CAL PLL and CAL FIL with the lid off. I've noticed that putting the lid on affects the frequency a bit, so I find myself struggling to adjust the oscillator so it will be right when I put the lid back on! Does anyone disagree with this? Vic K2VCO ++++++++++++++++ From: "Don Brown" To: "Vic Rosenthal" Cc: "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 21:53:33 -0600 Hi If the lid is only affecting the 4.000MHz oscillator you are correct. I d= o the cal with the lid off and It does not seem to affect the VFO. Howeve= r the bottom plate is another story. It must be in place with all of the = screws in place or the VFO will shift when it is installed. It will also = affect the calibration of the filters. Don Brown KD5NDB +++++++++++++++ From: "Don Wilhelm" To: "Vic Rosenthal" , "Don Brown" Cc: "Elecraft" Subject: Re: [Elecraft] CAL PLL with the top off Date: Thu, 31 Oct 2002 22:51:28 -0500 Vic, I have always done CAL PLL and CAL FIL with the top off (right after setting C22). I never thought about it - just did it because it was easier (you have to remove the probe after doing CAL FIL). My K2 is quite consistent in being able to zero to WWV at all the frequencies that I can receive, so something must be right. One warning though - I learned early on that the bottom cover MUST be on for CAL PLL and CAL FIL or subtle strange happenings occur. Some folks seem to be concerned about temp drift, but my shack is usually in a conditioned environment, so it is usually at a temperature that makes keeps my body comfortable too - and that is good enough for me. If I do get into a situation where the K2 is subjected to quite cold or quite warm conditions, you can bet that I will be busy keeping either the chatter of my teeth quiet or wiping the sweat from my brow and will not be so concerned about VFO calibration . +++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Vic Rosenthal'" Cc: "'Elecraft'" Subject: RE: [Elecraft] K2 w/KSB CW reverse BFO Date: Thu, 31 Oct 2002 19:58:34 -0800 Yes... As you know, during CAL PLL the LO oscillator frequency is measured and the control voltage required to put it on the desired frequency is measured and stored in memory. During CAL PLL is the only time the actual LO frequency is measured. In all subsequent operation, the logic puts the voltage level that was stored during CAL PLL on the VCO and ASSUMES that will put the LO back on the original frequency. If anything changes the frequency the LO will generate when supplied that control voltage, it will no longer be on the desired frequency. Things such as replacing covers, temperature changes, etc., all will introduce an error. Also any error in producing the exact voltage needed will produce a frequency error. That's where the resolution of the digital-to-analog converters (DACs) affects the frequency accuracy.. The same sort of errors occur with CAL FIL when the BFO frequency is measured and the corresponding control voltage is stored in memory. The whole CAL PLL and CAL FIL process is just a fancy way of calibrating the VFO and BFO "dials". In an old analog radio we'd have dials with pointers and paper scales that we could mark up to "calibrate" the LO and BFO. We'd measure each oscillator with a good frequency counter at several points over their ranges and put marks on the paper scale so we could reset the pointer to that place in the future. How close to the desired frequency would be when we turned the dial back to that mark at some future time would be subject to several things. First, we would NOT measure every possible dial setting. We'd take a bunch of samples, and then estimate the frequency in between. Halfway between two "marks' would be halfway between those two frequencies, etc. That's pretty good, but it's not perfect. The algorithm in the K2 logic does something similar. It defines certain points at which the frequency was measured and then calculates ("interpolates" to use the $5 word) the settings in between those points that will produce the frequencies in between those points. Secondly, when we marked the dial on the exact frequencies we did measure, the mark itself would be wide enough to see. That means that when we put the dial back on that frequency we have to squint and look carefully to get the pointer set exactly on the mark. We can't be absolutely exact. There will always be some 'resettability" error. That's what happens in the K2 because the DAC's don't have perfect resolution. Next, the original calibration was only as good as the accuracy of the frequency counter used to measure the frequency of the oscillator. Any error there will produce a permanent error in the calibration. That's why it's important to have the oscillator right on 4.00000 MHz so the internal frequency counter in the K2 will be as accurate as possible when running CAL PLL or CAL FIL. And FINALLY, and drift in the oscillators due to temperature or other environmental conditions - or anything else that will change the oscillator frequency without moving the "dial" such as replacing a cover, etc. - will add errors to the system. Once calibrated, the K2 is only as good as it's LO and BFO frequency stability over time and under changing environmental conditions. Ron AC7AC K2 # 1289 I've noticed that putting the lid on affects the frequency a bit, so I find myself struggling to adjust the oscillator so it will be right when I put the lid back on! Does anyone disagree with this? Vic K2VCO ++++++++++++++++ Date: Fri, 1 Nov 2002 09:40:52 -0500 (EST) From: kc4kgu at ENTERZONE.NET To: k6se at juno.com Cc: kc4kgu at ENTERZONE.NET, elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO On Thu, 31 Oct 2002 k6se at juno.com wrote: > KC4KGU wrote: > > "I then dialed up 4000.00 and verified that CW + SPOT was zerobeat with > the birdy and the I got a 600Hz tone verified with Spectrogram. > > I repeated with CW-R, USB at 3999.40 and LSB at 10000.60..... > > ...Does anyone see any error in my methodology as described above?" > ========== > First, I think you meant "LSB at 4000.60" above. Actually CW and CWR are > "USB" and "LSB" respectively (depending on the band the K2 is on), so > when you refer to "CWR" in terms of both USB and LSB it doesn't make > sense. OK. That should read (for clarity): I then dialed up 4000.00 and verified CW + SPOT was zerobeat with the birdy and that I showed exactly 600Hz beat tone on Spectrogram. Next, I selected CWR and verified that it also was zerobeat using SPOT and that it showed 600Hz beat tone on Spectrogram. Next, I selected USB and dialed 3999.40. I verified the 600Hz beat tone in Spectrogram. Next I selected LSB at 4000.60. I verified the 600Hz beat tone in Spectrogram. > > I may be wrong, but it sounds like you are adjusting the CW filters > offset by 600 Hz (your pitch preference) from the correct frequency. Nope. I just didn't articulate properly what it was that I had done. > An unmodulated carrier on exactly 4000.000 kHz should be heard with a > pitch of 600 Hz when your K2 is tuned to exactly 4000.000 kHz (not to > 4000.600 or 3999.400). If your K2's VFO readout is accurate, it should > read "4.000.00" when that received signal's pitch is 600 Hz, no matter > whether your receiver is on CW or CWR. > And that's exactly what it does. 4000.600 only produces a 600Hz beat tone in LSB SSB, 3999.40 for USB likewise. 73 de John - KC4KGU K2/100 #2490 +++++++++++++++ From: "Don Brown" To: "Wallace, Andy" , "Elecraft" Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO Date: Fri, 1 Nov 2002 09:06:05 -0600 Hi OK I will try to explain this. Your K2 will always transmit on the freque= ncy indicated on the dial (notice the frequency shift on the dial if you = turn on XIT when you transmit) When in receive the K2 MPU will offset the= VFO by the amount of your sidetone. That way if both operators are trans= mitting on the same frequency and one has a sidetone of 600 Hz and the ot= her has a side tone of 500 Hz then the operator with the 500 HZ tone will= hear the received CW signal as a 500 Hz tone while the operator with the= 600 Hz sidetone will hear 600 Hz. Even though they are both transmitting= on the same frequency. So if you are doing a performance test of your K2 then in CW mode listeni= ng to your MPU clock at 4.000 MHz you should hear your sidetone frequency= in CW and CW rev and at each filter setting. The tone should not change = frequency at all or very little. When you select sideband things are different. If there is no audio input= from the mic then there will be no RF out on transmit. The receive and t= ransmit frequency are the same. There is not an offset in the receiver. I= f you were to apply a 600 Hz tone to the mic input then the K2 would tran= smit a carrier offset +/-600 Hz depending on which sideband you selected.= The offset is determined by the frequency of the audio and the amplitude= of the RF carrier is determined by the amplitude of the audio. Ok now with the theory behind us the reason you need to set the VFO to 40= 00.60 on LSB or 3999.40 on USB is to get the 600 Hz offset so you will he= ar the tone. If you set the VFO to 4000.00 in USB or LSB then you are zer= o beat and you will hear nothing. Making this test checks to make sure yo= ur SSB filters are set up correctly. The test above checks out your CW fi= lters. You should not try to adjust your filters with these tests. Use Sp= ectrogram and a noise generator to set everything up then do the above te= sts to make sure everything is right. Don Brown KD5NDB ----- Original Message ----- From: Wallace, Andy Sent: Friday, November 01, 2002 8:08 AM To: elecraft at mailman.qth.net Subject: RE: [Elecraft] K2 w/KSB CW reverse BFO > -----Original Message----- > From: k6se at juno.com [mailto:k6se at juno.com] > An unmodulated carrier on exactly 4000.000 kHz should be heard with a > pitch of 600 Hz when your K2 is tuned to exactly 4000.000 kHz (not to > 4000.600 or 3999.400). If your K2's VFO readout is accurate, =20 > it should > read "4.000.00" when that received signal's pitch is 600 Hz, no matter > whether your receiver is on CW or CWR. But what frequency does the K2 transmit on, when set that way? I set my K1 frequency calibration on a separate receiver such that the display reads the transmit frequency, so I know I am always in-band. Whether the received freq is then off by the sidetone offset is not as important to me. K1 is CW only so I don't have to worry about SSB nets -- and even then, I cut my teeth on tube rigs that I had to readjust every few minutes. It was just a part of ham radio and not a huge hassle. -Andy ++++++++++++++++ To: awallace at mc.com, elecraft at mailman.qth.net Date: Fri, 1 Nov 2002 15:55:13 -0800 Subject: Re: [Elecraft] K2 w/KSB CW reverse BFO From: k6se at juno.com K6SE wrote: "An unmodulated carrier on exactly 4000.000 kHz should be heard with a pitch of 600 Hz when your K2 is tuned to exactly 4000.000 kHz (not to 4000.600 or 3999.400). If your K2's VFO readout is accurate, it should read "4.000.00" when that received signal's pitch is 600 Hz, no matter whether your receiver is on CW or CWR." ========== Andy Wallace asked: "But what frequency does the K2 transmit on, when set that way?" ----- K6SE's reply: If you are receiving a carrier on exactly 4000.000 kHz with a pitch of 600 Hz as outlined above, your transmit frequency will be 4000.000 kHz (assuming your RIT and XIT are off). ========== Andy Wallace wrote: "I set my K1 frequency calibrtion on a separate receiver such that the display reads the transmit frequency, so I know I am always in-band." ----- K6SE's reply: That's a good practice if you're close to the band edge. I assume that the K1's VFO readout accuracy is subject to the same problems as the K2 frequency drift with temperature. ========== Andy Wallace wrote: "Whether the received freq is then off by the sidetone offset is not as important to me. K1 is CW only so I don't have to worry about SSB nets -- and even then, I cut my teeth on tube rigs that I had to readjust every few minutes. It was just a part of ham radio and not a huge hassle." ----- K6SE's reply: My discussion was about CW and had nothing to do with alignment of the SSB filters in the K2. When a signal on SSB is tuned in and sounds normal, the K2's transmitter should be close to zero beat with the other station's frequency. On CW, being close to zero beat is important because the station you are calling may be using his receiver's 250 Hz filters and he may not find you unless he uses his receiver's RIT. If your frequency is offset by 600 Hz (as you described above), you'll even be outside of his 500 Hz xtal filter passband. It is especially irritating to operators during CW contests when calling stations are not close to zero beat. If you are just calling another station for a general ragchew type of QSO, then, as you said, it's not a huge hassle (as long as he finds your off-frequency signal). For most stations however, it would be a hassle, as well as the QSO taking up more bandwidth in our precious spectrum than necessary. If you notice that you have to use your RIT on most stations answering your CQs, that's a good indication that your receive and transmit frequencies do not coincide while your RIT is off. 73, de Earl, K6SE +++++++++++++++