CAL PLL and CAL FIL
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I know the CAL PLL process requires a CAL FIL after it
to make everything work correctly. My question is if I want to re-do the CAL FIL, do I need to do a CAL PLL first? I can't tell for sure from the manual, but it seems to me that I wouldn't need to. I'm thinking I should probably at least let the rig warm up to operating temp before re-doing CAL FIL however. -Ben K1NT _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Ben,
You can just do the CAL FIL alone. In fact, you can do CAL PLL alone too. Only one 'caution' - if you are to retain good dial calibration, be certain the 4 MHz reference oscillator is set properly before doing either CAL FIL or CAL PLL. The best method of setting the reference is using the "N6KR method" - see http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf for the instructions if you do not already know the procedure. You can do CAL FIL without setting the reference first, and your K2 will sound great, and the filters will work fine - the dial calibration may be a few more Hz off from what it should be, but that is the only 'bad' result. 73, Don W3FPR > -----Original Message----- > > I know the CAL PLL process requires a CAL FIL after it > to make everything work correctly. My question is if > I want to re-do the CAL FIL, do I need to do a CAL PLL > first? I can't tell for sure from the manual, but it > seems to me that I wouldn't need to. I'm thinking I > should probably at least let the rig warm up to > operating temp before re-doing CAL FIL however. > > -Ben K1NT > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.7/618 - Release Date: 1/6/2007 7:47 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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I have just acquired a used K2 (includes noise blanker, SSB adapter,
internal tuner) which seems to work fine (hears well, and I have made some 4w SSB contacts across the Caribbean islands), except for two little issues: first, the AF gain control, when turned fully anti-clockwise (7 o'clock position), does not silence the rig, although the control does work in reducing/increasing audio volume over the rest of its range. Volume at the minimum position is about where it would be if a normal rig were at the 9 o'clock position. I pulled the knob off and tried the bare control: no change. second, if the RF gain control is turned or touched at all, the rig immediately goes silent and all the bars in the bar-graph meter are illuminated. Over a period of about three seconds the bars are extinguished, from right to left, and the sound comes back up. The control itself works in limiting RF gain normally, depending on the position to which it is turned. I have another K2 (no noise blanker, no internal tuner) which works entirely normally, so I know this behaviour is unusual. Just wondered whether anyone had any previous experience with these phenomena. My impression is that the rig worked normally in the past, but may not have been used for the last couple of years. Serial No. is 2086. I got it from the original owner; although it had not been built by him, but by one of the for-hire builders. Would replacing the pots help? Grateful for any assistance. Alan 8P9BM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: K2: AF and RF volume controls
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Alan SP9BM wrote:
I have just acquired a used K2 (includes noise blanker, SSB adapter, internal tuner) which seems to work fine (hears well, and I have made some 4w SSB contacts across the Caribbean islands), except for two little issues: first, the AF gain control, when turned fully anti-clockwise (7 o'clock position), does not silence the rig, although the control does work in reducing/increasing audio volume over the rest of its range. Volume at the minimum position is about where it would be if a normal rig were at the 9 o'clock position. I pulled the knob off and tried the bare control: no change. second, if the RF gain control is turned or touched at all, the rig immediately goes silent and all the bars in the bar-graph meter are illuminated. Over a period of about three seconds the bars are extinguished, from right to left, and the sound comes back up. The control itself works in limiting RF gain normally, depending on the position to which it is turned. I have another K2 (no noise blanker, no internal tuner) which works entirely normally, so I know this behaviour is unusual. Just wondered whether anyone had any previous experience with these phenomena. My impression is that the rig worked normally in the past, but may not have been used for the last couple of years. Serial No. is 2086. I got it from the original owner; although it had not been built by him, but by one of the for-hire builders. Would replacing the pots help? Grateful for any assistance. --------------------------------- That sounds like a bad RF gain pot or a missed solder connection in the RF Gain or AGC circuits that has become 'noisy'. It could be a bad pot. Touching the pot causing it to act up is a very good clue. I'd look very closely at the connections to the pot first. The audio gain control action you're seeing is also normal for that vintage K2, but there is help available. The original AF gain control design used the pot to "ground" the audio, rather than control the gain. To be more precise, the K2 uses a "push-pull" balanced audio line between stages so the traces on the pc boards won't pick up digital noise (such noise will be 'common mode' on both of the audio circuit traces and is easily suppressed). The pot was across the balanced lines so it "shorted out" the audio when turned fully down. Unfortunately, the pots develop a little bit of resistance at the "minimum' setting over time and so won't turn the gain all the way down any longer! The gain control circuit was redesigned to provide better control that does not require such low resistance at the minimum setting. It also changes the audio control to be logarithmic in nature, like most audio controls. That happened in 2001 and was implemented at about S/N 3000, if I recall correctly. However, Elecraft, as usual, provided instructions for owners of older K2s to upgrade their rigs with the new circuit. The mod requires changing a few traces and adding a couple of wires for the new circuit, but no other parts are needed. Your present AF gain control is probably fine. You'll need a little bit of wire. I used some stranded wire scavenged from a bit of old telephone extension cable. The mod is on the Elecraft web site at: http://www.elecraft.com/Apps/K2_AF_pot/K2_AF_gain_app_note.pdf For an Adobe Acrobat PDF file or http://www.elecraft.com/Apps/K2_AF_pot/K2_AF_gain_app_note.htm For the same thing as a web page. I incorporated that mod in my K2 S/N 1289 and it works like a champ! Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Don Wilhelm-3
If you have the KDSP2 installed, can you still use the "N6KR method" to set
the reference? I would think you would want it in Bypass. Dohn N8EWY -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Don Wilhelm Sent: Monday, January 08, 2007 9:01 AM To: [hidden email]; [hidden email] Subject: RE: [Elecraft] CAL PLL and CAL FIL Ben, You can just do the CAL FIL alone. In fact, you can do CAL PLL alone too. Only one 'caution' - if you are to retain good dial calibration, be certain the 4 MHz reference oscillator is set properly before doing either CAL FIL or CAL PLL. The best method of setting the reference is using the "N6KR method" - see http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf for the instructions if you do not already know the procedure. You can do CAL FIL without setting the reference first, and your K2 will sound great, and the filters will work fine - the dial calibration may be a few more Hz off from what it should be, but that is the only 'bad' result. 73, Don W3FPR > -----Original Message----- > > I know the CAL PLL process requires a CAL FIL after it > to make everything work correctly. My question is if > I want to re-do the CAL FIL, do I need to do a CAL PLL > first? I can't tell for sure from the manual, but it > seems to me that I wouldn't need to. I'm thinking I > should probably at least let the rig warm up to > operating temp before re-doing CAL FIL however. > > -Ben K1NT > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.7/618 - Release Date: 1/6/2007 7:47 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.410 / Virus Database: 268.16.7/619 - Release Date: 1/7/2007 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Dohn,
There is no relationship between setting the 4 MHz reference (using any method) and the KDSP2. The problem with the KDSP2 (and the KAF2 to a lesser extent) is that it contains a low pass audio filter which will mask seeing the upper frequency end of the actual audio passband when aligning the filters (CAL FIL). I know the bypass function in the KDSP2 is available, but I just get it out of the picture entirely by removing it when viewing the filters with Spectroogram - it only requires pulling the top module off, removing the screw and installing 2 jumpers - but then that is my choice, you can use DSP bypass just as well (the KAF2 has a switch to remove the low pass filter). 73, Don W3FPR > -----Original Message----- > > If you have the KDSP2 installed, can you still use the "N6KR > method" to set > the reference? I would think you would want it in Bypass. > > Dohn N8EWY > > -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.7/619 - Release Date: 1/7/2007 6:29 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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