K2 TX power cutoff?
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Occasionally, when at 100% SSB power (15.2w), I get
audio reports indicating my transmitter is cutting back my power. I also see "Hi Cur" flash on sometimes. I have the Cal Cur set to 3.7A. Receive current is i0.28 on a SEC 1223 (23a) switching power supply / backup SLA battery setup running at 13.7v. I fixed the problem by cutting back power to 15.0w. Q: is this normal? Is 3.7A for Cal Cur too high? Rig is K2 / KSB2 / KAT2 / KIO2 / K160RX. Freq is 7.253.50 Lsb into a 40m inverted V @ 40' Untuned SWR is 1.4:1 but I'm using a KAT2 so my SWR is 1:1. -- 73 de Ken KGØWX - Flying Pigs #-1055 Elecraft K2 #4913 _______________________________________________ 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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Ken, KG0WX asked:
I also see "Hi Cur" flash on sometimes. I have the Cal Cur set to 3.7A. Receive current is i0.28 on a SEC 1223 (23a) switching power supply / backup SLA battery setup running at 13.7v. I fixed the problem by cutting back power to 15.0w. Q: is this normal? Is 3.7A for Cal Cur too high? ------------------------- The most obvious suggestion is to raise your current limit a bit. The current demands go up fast as you push the rig to full power. I'm sure you considered that and, as you probably suspected, that may not be the best solution. Two questions to consider are: 1) Are you setting the POWER for a level above what the rig will actually produce? If you aren't sure, set the POWER to maximum and press TUNE. Whatever power is indicated is the actual maximum power the K2 will produce on that band. Don't set the POWER control above that point. You won't get any additional power output. Remember, the reading you see when you adjust the POWER control is the *requested* power, not the actual power. Setting it above what the rig will produce does no good at all. 2) Do you really want to run more than 10 watts on SSB? The linearity of the finals in the K2 decreases as the power level is raised above 10 watts. That's not an issue on CW but if you want the cleanest signal the rig can produce on SSB, you should limit it to ten watts. Ten watts is only 1.8 dB below 15 watts. On most S-meters that less than 1/4 of on S-unit. 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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----- Original Message -----
From: "Ron D'Eau Claire" <[hidden email]> To: "'Ken Bessler'" <[hidden email]>; "'Elecraft Main Group'" <[hidden email]> Sent: Saturday, August 06, 2005 6:50 PM Subject: RE: [Elecraft] K2 TX power cutoff? The most obvious suggestion is to raise your current limit a bit. The current demands go up fast as you push the rig to full power. I'm sure you considered that and, as you probably suspected, that may not be the best solution. Two questions to consider are: 1) Are you setting the POWER for a level above what the rig will actually produce? If you aren't sure, set the POWER to maximum and press TUNE. Whatever power is indicated is the actual maximum power the K2 will produce on that band. Don't set the POWER control above that point. You won't get any additional power output. Remember, the reading you see when you adjust the POWER control is the *requested* power, not the actual power. Setting it above what the rig will produce does no good at all. 2) Do you really want to run more than 10 watts on SSB? The linearity of the finals in the K2 decreases as the power level is raised above 10 watts. That's not an issue on CW but if you want the cleanest signal the rig can produce on SSB, you should limit it to ten watts. Ten watts is only 1.8 dB below 15 watts. On most S-meters that less than 1/4 of on S-unit. Ron AC7AC ================================================= Thanks, Ron. I normally run only 5w but this was on a local rag chew and I wanted to see how hot the case got near the finals. It's been my experience that even with marginal conditions (when even QRO dosen't work), as long as you have a decent antenna, 5w is plenty even on SSB. Now if I'm ever forced to use a marginal antenna, I'll consider going to 10w (not 15.2 - thanks for the heads up!) or maybe 100w. -- 73 de Ken KGØWX - Flying Pigs #-1055 Elecraft K2 #4913 _______________________________________________ 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 |
QRP or QRO (WAS:] K2 TX power cutoff?)
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Ken wrote:
It's been my experience that even with marginal conditions (when even QRO doesn't work), as long as you have a decent antenna, 5w is plenty even on SSB. Now if I'm ever forced to use a marginal antenna, I'll consider going to 10w (not 15.2 - thanks for the heads up!) or maybe 100w. ------------------------------------------------------------------------- I enjoy QRP work too, when I'm working other QRP stations. I keep my power output near 5 watts around the QRP calling frequencies. When I'm roaming the bands and have the wick turned up on my K2/100 to a full 100 watts out, and if another station says they're running QRP AND has a decent signal, I'll QRP to match. If the other signal isn't real good, it's not uncommon for that operator to have trouble copying if I QRP as well so I'll stay QRO. Personally, I get a kick out of digging for whispers in the noise at times, so I'm likely to respond to a very weak signal and not complain about a signal dancing in the noise. Of course, when CDX are good even QRPp can boom in from almost anywhere. When considering QRO, I avoid getting excited unless I can jump my power by a factor of 8 to 10. For example, it makes sense to me to add a 100 watt amp to a 10 to 15 watt K2. That pushes up my signal about 1-1/2 S-units at the other end. Any less of an increase is of marginal value, in my experience. So, if I were to QRO further I'd not consider it worthwhile to go from 100 watts unless I ran something in the range of 800 to 1000 watts. Most QRPers have had the fun of going extreme QRPp when the bands are open and noticing how tiny of a signal can still be copied. But there's another experiment that's also very informative, even when the bands aren't at their best. If copy is decent, have the other station cut power by half - 3-dB or about 1/2 S-unit - and see if you can really notice the difference. Sometimes I can't even be sure of a 6 dB change, a drop to 1/4 the original power by the other station, under typical band conditions with QSB, etc. 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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Hi all,
My KPA100 seems to be performing well. However, when I'm in tune at low power I get about 8 Watts out and with High power tune is producing about 40 Watts out. I think its supposed to be 2 W and 20 W. What should I do? Steve, W2MY -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.1/64 - Release Date: 8/4/2005 _______________________________________________ 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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Steve,
How are you determining the power output? Is the 8 watts and the 40 watts what is indicated on the K2 or what is indicated on an external wattmeter. If it is an external wattmeter, then the answer is easy - calibrate the forward power pot in the KPA100. OTOH, if the power indication is on the K2 display, look carefully at your dummy load. A good 50 ohm dummy load connected directly to the K2 should provide a power output of 2 watts and 20 watts on the K2 display (but the KPA100 wattmeter still needs to be calibrated before the actual power is equal to what the K2 displays). 73, Don W3FPR > -----Original Message----- > > > Hi all, > My KPA100 seems to be performing well. However, when I'm in tune at low > power I get about 8 Watts out and with High power tune is > producing about 40 > Watts out. I think its supposed to be 2 W and 20 W. What should I do? > > Steve, W2MY > > No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.2/65 - Release Date: 8/7/2005 _______________________________________________ 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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Hi Don,
Sorry, I forgot to mention that I have tried using several Wattmeters after the KPA100 and before the KAT100, and they all pretty much agree. I will calibrate the pot as you suggest. Thanks. Steve, W2MY -----Original Message----- From: W3FPR - Don Wilhelm [mailto:[hidden email]] Sent: Monday, August 08, 2005 7:33 PM To: Steven Pituch; 'Elecraft Main Group' Subject: RE: [Elecraft] 8W Lo & 40W Hi in Tune Steve, How are you determining the power output? Is the 8 watts and the 40 watts what is indicated on the K2 or what is indicated on an external wattmeter. If it is an external wattmeter, then the answer is easy - calibrate the forward power pot in the KPA100. OTOH, if the power indication is on the K2 display, look carefully at your dummy load. A good 50 ohm dummy load connected directly to the K2 should provide a power output of 2 watts and 20 watts on the K2 display (but the KPA100 wattmeter still needs to be calibrated before the actual power is equal to what the K2 displays). 73, Don W3FPR -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.1/64 - Release Date: 8/4/2005 _______________________________________________ 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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Steve,
If you have both the KPA100 and the KAT100, the wattmeter in the KAT100 is the one that will be used - so calibrate the wattmeter in the KPA100 without the KAT100 attached (just use a good 50 ohm dummy load), and then set the KAT100 wattmeter as instructed in the manual and all should fall in line. 73, Don W3FPR > -----Original Message----- > From: Steven Pituch [mailto:[hidden email]] > Sent: Monday, August 08, 2005 8:52 PM > To: [hidden email]; 'Elecraft Main Group' > Subject: RE: 8W Lo & 40W Hi in Tune > > > Hi Don, > Sorry, I forgot to mention that I have tried using several > Wattmeters after > the KPA100 and before the KAT100, and they all pretty much agree. I will > calibrate the pot as you suggest. Thanks. > > Steve, W2MY > > -----Original Message----- > From: W3FPR - Don Wilhelm [mailto:[hidden email]] > Sent: Monday, August 08, 2005 7:33 PM > To: Steven Pituch; 'Elecraft Main Group' > Subject: RE: [Elecraft] 8W Lo & 40W Hi in Tune > > Steve, > > How are you determining the power output? Is the 8 watts and the 40 watts > what is indicated on the K2 or what is indicated on an external wattmeter. > If it is an external wattmeter, then the answer is easy - calibrate the > forward power pot in the KPA100. > > OTOH, if the power indication is on the K2 display, look carefully at your > dummy load. A good 50 ohm dummy load connected directly to the K2 should > provide a power output of 2 watts and 20 watts on the K2 display (but the > KPA100 wattmeter still needs to be calibrated before the actual power is > equal to what the K2 displays). > > 73, > Don W3FPR > > > -- > No virus found in this outgoing message. > Checked by AVG Anti-Virus. > Version: 7.0.338 / Virus Database: 267.10.1/64 - Release Date: 8/4/2005 > > > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.338 / Virus Database: 267.10.2/65 - Release Date: 8/7/2005 > No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.2/65 - Release Date: 8/7/2005 _______________________________________________ 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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