RE: [Elecraft] KAT100: Strange K2/100 Behavior During Tune
If it is RF feedback, the proper way to deal with it is at the source - in your antenna system. An easy way to check it is to cut a quarterwave wire for each band that is troublesome - attach one end of the wires to the ground terminal on your tuner and the other end just stretches out and attaches to nothing excpet an insulator. There will be high RF Voltage on the open end of the wires, so keep them clear of human and pet contact and keep them far enough away from objects to prevent arc-overs (treat the far ends sort-of-like the end af an antenna). If these wires correct the problem, then you do have work to do on the antenna system. If they do not help, then you can look further for a K2/100 or KAT100 problem. From your description, I would think something is causing a very high current draw (even for a very short time) - your power supply may be going into foldback limiting and the K2 powers off momentarily. The other possibility is that the resettable fuse in th ebase K2 is tripping and causing the power off condition (yes - it is powering off since you see the ELECrAFt on the display). Is this by any chance happening most frequently on 40 meters? 73, Don W3FPR -Original Message- I have a K2/100 with a KAT100. For the most part, all works well as expected. Intermittently, though, when I press the TUNE button, the KAT100 will chatter briefly as if finding a match, and then it suddenly stops and the K2 acts as if its CPU has been re-set; the bargraph and the LCD go blank briefly, then the ELECrAFt sign-on message appears briefly and finally the frequency is re-displayed. During this time, however, the power supply indications are normal and the LCD backlight remains on. This problem seems to be frequency-dependent and seems to happen more often at high power, which leads me to think it is an RF feedback issue. However, I've noticed that turning the power down to bottom end of the high-power range (approx 12 W) usually doesn't help, yet turning it slightly lower than that, to get into the low-power range (approx 10 W), does. Any advice on how to solve it? Thanks ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] KAT100: Strange K2/100 Behavior During Tune
In this case the antenna is a simple coax-fed 40M dipole with a balun at the feedpoint. Without the KAT100 in line the SWR is approx 1.2 to 1 at 7100 where the problem occurs. A quick check shows that yes, the problem seems to occur only on 40m. I also noticed that other accessories on the same power supply re-set themselves when it happens, supporting the foldback limiting theory and the work-around that Tom posted and Mark pointed out. However, it happens only when the KAT100 is in line; I cannot reproduce it at any frequency or power level when the KAT100 is disabled. - Original Message - From: Don Wilhelm [EMAIL PROTECTED] To: Jonathan Taylor, K1RFD [EMAIL PROTECTED]; elecraft@mailman.qth.net Sent: Saturday, September 16, 2006 4:47 PM Subject: RE: [Elecraft] KAT100: Strange K2/100 Behavior During Tune If it is RF feedback, the proper way to deal with it is at the source - in your antenna system. An easy way to check it is to cut a quarterwave wire for each band that is troublesome - attach one end of the wires to the ground terminal on your tuner and the other end just stretches out and attaches to nothing excpet an insulator. There will be high RF Voltage on the open end of the wires, so keep them clear of human and pet contact and keep them far enough away from objects to prevent arc-overs (treat the far ends sort-of-like the end af an antenna). If these wires correct the problem, then you do have work to do on the antenna system. If they do not help, then you can look further for a K2/100 or KAT100 problem. From your description, I would think something is causing a very high current draw (even for a very short time) - your power supply may be going into foldback limiting and the K2 powers off momentarily. The other possibility is that the resettable fuse in th ebase K2 is tripping and causing the power off condition (yes - it is powering off since you see the ELECrAFt on the display). Is this by any chance happening most frequently on 40 meters? 73, Don W3FPR -Original Message- I have a K2/100 with a KAT100. For the most part, all works well as expected. Intermittently, though, when I press the TUNE button, the KAT100 will chatter briefly as if finding a match, and then it suddenly stops and the K2 acts as if its CPU has been re-set; the bargraph and the LCD go blank briefly, then the ELECrAFt sign-on message appears briefly and finally the frequency is re-displayed. During this time, however, the power supply indications are normal and the LCD backlight remains on. This problem seems to be frequency-dependent and seems to happen more often at high power, which leads me to think it is an RF feedback issue. However, I've noticed that turning the power down to bottom end of the high-power range (approx 12 W) usually doesn't help, yet turning it slightly lower than that, to get into the low-power range (approx 10 W), does. Any advice on how to solve it? Thanks ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] KAT100: Strange K2/100 Behavior During Tune
Here is another simple explanation. Perhaps it is voltage drop on your power supply. You probably have the best match and most power output on the 40m band, Is your power supply up to it? A simple way to test this is to turn the power out down by 30W or so. Not enough db wise to make a difference if it is an rf interefence issue but will considerably reduce the demand on your power supply. Raj, N2RD On Sep 16, 2006, at 5:20 PM, Jonathan Taylor, K1RFD wrote: In this case the antenna is a simple coax-fed 40M dipole with a balun at the feedpoint. Without the KAT100 in line the SWR is approx 1.2 to 1 at 7100 where the problem occurs. A quick check shows that yes, the problem seems to occur only on 40m. I also noticed that other accessories on the same power supply re-set themselves when it happens, supporting the foldback limiting theory and the work-around that Tom posted and Mark pointed out. However, it happens only when the KAT100 is in line; I cannot reproduce it at any frequency or power level when the KAT100 is disabled. - Original Message - From: Don Wilhelm [EMAIL PROTECTED] To: Jonathan Taylor, K1RFD [EMAIL PROTECTED]; elecraft@mailman.qth.net Sent: Saturday, September 16, 2006 4:47 PM Subject: RE: [Elecraft] KAT100: Strange K2/100 Behavior During Tune If it is RF feedback, the proper way to deal with it is at the source - in your antenna system. An easy way to check it is to cut a quarterwave wire for each band that is troublesome - attach one end of the wires to the ground terminal on your tuner and the other end just stretches out and attaches to nothing excpet an insulator. There will be high RF Voltage on the open end of the wires, so keep them clear of human and pet contact and keep them far enough away from objects to prevent arc-overs (treat the far ends sort-of-like the end af an antenna). If these wires correct the problem, then you do have work to do on the antenna system. If they do not help, then you can look further for a K2/100 or KAT100 problem. From your description, I would think something is causing a very high current draw (even for a very short time) - your power supply may be going into foldback limiting and the K2 powers off momentarily. The other possibility is that the resettable fuse in th ebase K2 is tripping and causing the power off condition (yes - it is powering off since you see the ELECrAFt on the display). Is this by any chance happening most frequently on 40 meters? 73, Don W3FPR -Original Message- I have a K2/100 with a KAT100. For the most part, all works well as expected. Intermittently, though, when I press the TUNE button, the KAT100 will chatter briefly as if finding a match, and then it suddenly stops and the K2 acts as if its CPU has been re-set; the bargraph and the LCD go blank briefly, then the ELECrAFt sign-on message appears briefly and finally the frequency is re-displayed. During this time, however, the power supply indications are normal and the LCD backlight remains on. This problem seems to be frequency-dependent and seems to happen more often at high power, which leads me to think it is an RF feedback issue. However, I've noticed that turning the power down to bottom end of the high-power range (approx 12 W) usually doesn't help, yet turning it slightly lower than that, to get into the low-power range (approx 10 W), does. Any advice on how to solve it? Thanks ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] KAT100: Strange K2/100 Behavior During Tune
Raj, Fine analysis, but consider that the K2/100 has more gain and better efficiency on 40 meters than on most of the other bands, so the current drain on 40 meters should be less for any given power output level, and under normal operating conditions, the current drain should be at a minimum on 40 meters. I fear that the power supply shutdown may be a result of some kind of parasitic that happens when the KPA100 is set for 40 meters. For some unexplained reason, this shows up most commonly with the KAT100 attached. There may be more later, I understand that the design engineers at Elecaft are currently working on this, so patience is called for - it will likely be corrected when all the Is are dotted and the Ts are crossed (soon). In the meantime, Tom Hammond has compiled information on this behavior - see www.n0ss.net - look for the file on 'KPA100 40M Parasitic circumvention'. 73, Don W3FPR -Original Message- Here is another simple explanation. Perhaps it is voltage drop on your power supply. You probably have the best match and most power output on the 40m band, Is your power supply up to it? A simple way to test this is to turn the power out down by 30W or so. Not enough db wise to make a difference if it is an rf interefence issue but will considerably reduce the demand on your power supply. Raj, N2RD On Sep 16, 2006, at 5:20 PM, Jonathan Taylor, K1RFD wrote: In this case the antenna is a simple coax-fed 40M dipole with a balun at the feedpoint. Without the KAT100 in line the SWR is approx 1.2 to 1 at 7100 where the problem occurs. A quick check shows that yes, the problem seems to occur only on 40m. I also noticed that other accessories on the same power supply re-set themselves when it happens, supporting the foldback limiting theory and the work-around that Tom posted and Mark pointed out. However, it happens only when the KAT100 is in line; I cannot reproduce it at any frequency or power level when the KAT100 is disabled. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
