Re: [Elecraft] [K2] Low power output
Hi Don, many thanks for all kind help and ideas. I will try to call him in order to explain all of these steps to be checked. Most important is to double check what the real power is from his K2 as I do not know if he measured the output power correctly with his external equipment. Again Don thanks for your kind help and time! btw: if you remember our son's K1 is still waiting on the shelf to be finished the alignment...:) best 73 - Petr, OK1RP On Wed, Sep 4, 2019, at 4:29 PM, Don Wilhelm wrote: > Petr, > > The specification for the K2 is for 10 watts or greater. Most will go > to 12 watts on 40 and 30 meters with an adequate power supply voltage > while few can achieve 15 watts on all bands. > > There is nothing specific to the KPA100 option that would cause low > power output from the base K2. > However, there are a few things to check. > > First check the value of R98 on the bottom of the board. The normal > value is 270 ohms, but after the addition of the KPA100, some > experienced power oscillation due to the added RF Gain, and that value > may have been increased to damp the oscillation. > > Then check to make certain T4 was not wound for "greater efficiency at 5 > watts" with a 2:2:1:1 ratio instead of the normal 2:3:1:1 ratio - count > the number of white turns on T4. That 'more efficient' T4 is actually > less efficient above 5 watts and should never be used with the KSB2 > option or the KPA100. > > If there is also HiCur as well as low power then the problem is either > with T4 or the Low Pass Filter. > > Make certain the power supply leads are tight and large enough to keep > the voltage drop low - a power source with at least 13.8 volts should be > used and the voltage should not drop below 12.5 during transmit. 15 > watts is not possible with a lower voltage, and the output on 12 and 10 > meters may be less. 10 watts or more meets specification. > > If those checks do not provide the answer, then he will have to do the > "Transmit Signal Tracing" in Appendix A of the manual to identify the > first stage with less than the expected RF voltage output. > > 73, > Don W3FPR > > On 9/4/2019 6:47 AM, Petr, OK1RP/M0SIS wrote: > > Hi folks, > > > > my colleque got as birthday gift from family the K2. All seems ok, receiver > > works excellent. > > The only issue he found is the low power output thru all bands. He can not > > get 15W but something > > below 10W... He mentioned in last email that preview owner had installed > > KPA100 option which > > has been removed probably before selling. > > Is there something related to KPA100 which could be modified and need to be > > now set back to get > > 15W from his K2 please? > > > -- 73 - Petr, OK1RP -- B: http://goo.gl/Fd2JhJ MeWe: https://bit.ly/2HGPoDx MeWe: https://bit.ly/2FmwvDt __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] [K2] Low power output
Petr, The specification for the K2 is for 10 watts or greater. Most will go to 12 watts on 40 and 30 meters with an adequate power supply voltage while few can achieve 15 watts on all bands. There is nothing specific to the KPA100 option that would cause low power output from the base K2. However, there are a few things to check. First check the value of R98 on the bottom of the board. The normal value is 270 ohms, but after the addition of the KPA100, some experienced power oscillation due to the added RF Gain, and that value may have been increased to damp the oscillation. Then check to make certain T4 was not wound for "greater efficiency at 5 watts" with a 2:2:1:1 ratio instead of the normal 2:3:1:1 ratio - count the number of white turns on T4. That 'more efficient' T4 is actually less efficient above 5 watts and should never be used with the KSB2 option or the KPA100. If there is also HiCur as well as low power then the problem is either with T4 or the Low Pass Filter. Make certain the power supply leads are tight and large enough to keep the voltage drop low - a power source with at least 13.8 volts should be used and the voltage should not drop below 12.5 during transmit. 15 watts is not possible with a lower voltage, and the output on 12 and 10 meters may be less. 10 watts or more meets specification. If those checks do not provide the answer, then he will have to do the "Transmit Signal Tracing" in Appendix A of the manual to identify the first stage with less than the expected RF voltage output. 73, Don W3FPR On 9/4/2019 6:47 AM, Petr, OK1RP/M0SIS wrote: Hi folks, my colleque got as birthday gift from family the K2. All seems ok, receiver works excellent. The only issue he found is the low power output thru all bands. He can not get 15W but something below 10W... He mentioned in last email that preview owner had installed KPA100 option which has been removed probably before selling. Is there something related to KPA100 which could be modified and need to be now set back to get 15W from his K2 please? __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] [K2] Low power output
Hi folks, my colleque got as birthday gift from family the K2. All seems ok, receiver works excellent. The only issue he found is the low power output thru all bands. He can not get 15W but something below 10W... He mentioned in last email that preview owner had installed KPA100 option which has been removed probably before selling. Is there something related to KPA100 which could be modified and need to be now set back to get 15W from his K2 please? Thanks, - 73 - Petr, OK1RP "Apple & Elecraft freak" B:http://ok1rp.blogspot.com MeWe: https://bit.ly/2HGPoDx MeWe: https://bit.ly/2FmwvDt -- Sent from: http://elecraft.365791.n2.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Thanks Don, I measured at 4000KHz (5.87V) and at 3500KHz (1.85V) so it is within the range you gave me. I need now to take my RF probe and go further. Again, many thanks for the help you provided. Greatly appreciated. 73, Phil. On 02.10.2016 00:43, Don Wilhelm wrote: > Phil, > > One thing you can easily and quickly check is that the VCO signal has not > gone out of range. > Set the K2 to 4000kHz and measure the left end of R30 - it should not be > above 7.5 volts (nearer to 6 volts is better). Then tune to 3500kHz and > again measure the left end of R30 - it should not be below 1.5 volts. If it > is within that range, the VCO is properly locking. > > If it is not within that range, do the VCO Alignment as indicated in the > manual on page 64 (if the manual is older, you will find it on page 55). > > 73, > Don W3FPR __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Phil, One thing you can easily and quickly check is that the VCO signal has not gone out of range. Set the K2 to 4000kHz and measure the left end of R30 - it should not be above 7.5 volts (nearer to 6 volts is better). Then tune to 3500kHz and again measure the left end of R30 - it should not be below 1.5 volts. If it is within that range, the VCO is properly locking. If it is not within that range, do the VCO Alignment as indicated in the manual on page 64 (if the manual is older, you will find it on page 55). 73, Don W3FPR On 10/1/2016 2:00 PM, Philippe wrote: On Thu, Sep 29, 2016 at 07:12:58PM -0400, Don Wilhelm wrote: Phil, Don't be too quick to draw that conclusion. Note that everything in the Low Pass Filter will appear to be connected to ground at DC. If you want to make a valid DC resistance check, you have to lift lead 4 of T4 and re-measure. Thanks Don. You was right, the 2 relays are fine (tested after I lifted T4 lead 4 as suggested). I checked also L16 and L17. I removed L17 because I wasn't sure it was properly stripped, and re-soldered it. I still have an issue on RX and TX on 80m. :( I need to go 'deeper'. 73, Phil. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Phil, The next logical step is to do Transmit Signal Tracing as described in Appendix E of the manual. Use 80 meters instead of 40. When you come to the first point where the RF Voltage is substatially less than the Expected value, that is the output of the problem stage. You can then examine the schematic to see the components associated with that stage and evaluate each individually. 73, Don W3FPR On 10/1/2016 2:00 PM, Philippe wrote: On Thu, Sep 29, 2016 at 07:12:58PM -0400, Don Wilhelm wrote: I need to go 'deeper'. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
On Thu, Sep 29, 2016 at 07:12:58PM -0400, Don Wilhelm wrote: > Phil, > > Don't be too quick to draw that conclusion. > Note that everything in the Low Pass Filter will appear to be connected to > ground at DC. If you want to make a valid DC resistance check, you have to > lift lead 4 of T4 and re-measure. > Thanks Don. You was right, the 2 relays are fine (tested after I lifted T4 lead 4 as suggested). I checked also L16 and L17. I removed L17 because I wasn't sure it was properly stripped, and re-soldered it. I still have an issue on RX and TX on 80m. :( I need to go 'deeper'. 73, Phil. -- Philippe Givet F5IYJ / NK2F __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Phil, Don't be too quick to draw that conclusion. Note that everything in the Low Pass Filter will appear to be connected to ground at DC. If you want to make a valid DC resistance check, you have to lift lead 4 of T4 and re-measure. Good that you have isolated it to the base K2. Take a good look at the toroid leads for L16 and L17. You should not see any enamel on the solder side and there should not be a ring around the toroid leads - that is an indication that the lead was not properly stripped and tinned. In addition, there should be a bit of tinned lead exposed on the component side. It would be nice to know if the prior owner operated it on 80 meters. The relays in the base K2 are latching type, so you can set to the band of interest and then turn power off to make resistance readings at the relay contacts. 73, Don W3FPR On 9/29/2016 6:29 PM, Philippe wrote: Hi, thanks Matt & Don for your messages. The issue is located on the K2, not on the PA I checked K3 and K8. K3 looks fine but it looks like I have a shortcut between the pins 7-8-9. I will get another relay and change K8. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Hi, thanks Matt & Don for your messages. The issue is located on the K2, not on the PA I checked K3 and K8. K3 looks fine but it looks like I have a shortcut between the pins 7-8-9. I will get another relay and change K8. Thanks again Cheers, -- Phil F5IYJ / NK2F __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Phillippe, There are several things that could be wrong. First determine if it is a problem with the base K2 or the KPA100. To accomplish that, you will have to physically remove the KPA100, unplug the 4 cables and power the base K2 from the 2.1mm coaxial power jack on the lower rear panel. It could be the 80 meter Low pass Filter - either in the base K2 or the KPA100 - badly tinned toroid leads are a common cause. It is also possible that the LPF relay or the BPF relay for 80 meters is not working properly - look at K3 and K8 in the base K2 and K11 and K12 in the KPA100. If the relay case has been damaged, replace it. 73, Don W3FPR On 9/29/2016 3:31 AM, Philippe wrote: Hi, I bought an used K2/100 with an issue on 80m: - RF is low (less than 1 watt) even when PWR set to 100W - reception sensibility is low as well, I need to switch the PRE to hear something on the band. - all other bands are doing fine (good sensibility, 100W+) __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 - low power/reception on 80m
Sticky relay? 73, Matt VK2RQ On Thu, Sep 29, 2016 at 5:32 PM +1000, "Philippe" wrote: Hi, I bought an used K2/100 with an issue on 80m: - RF is low (less than 1 watt) even when PWR set to 100W - reception sensibility is low as well, I need to switch the PRE to hear something on the band. - all other bands are doing fine (good sensibility, 100W+) I first though about the band filter but I didn't success to get any RF increase when re-tuning L3/L4. Do you have an idea where I can start? Thanks -- Phil F5IYJ / NK2F __ 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 Message delivered to matt.vk...@gmail.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 Message delivered to arch...@mail-archive.com
[Elecraft] K2 - low power/reception on 80m
Hi, I bought an used K2/100 with an issue on 80m: - RF is low (less than 1 watt) even when PWR set to 100W - reception sensibility is low as well, I need to switch the PRE to hear something on the band. - all other bands are doing fine (good sensibility, 100W+) I first though about the band filter but I didn't success to get any RF increase when re-tuning L3/L4. Do you have an idea where I can start? Thanks -- Phil F5IYJ / NK2F __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Low power output
Dave, It may be that the wattmeter in the KPA100 needs calibration - and is the most likely reason. Dig out the KPA100 manual and look at page 48. Do the SWR Bridge Null Adjustment first. Then do the Power Calibration. There may be some variability in the calibration from band to band because the diode response is not entirely linear with respect to frequency, but if you do the calibration on 40 meters or 30 meters, it should be quite reasonable for all bands. 73, Don W3FPR On 11/25/2014 12:55 PM, W8OV wrote: I recently acquired a very clean K2/100 with external KAT100 ATU. I have a K3/100 and its power output agrees closely with the readings of both Bird and Elecraft W2 watt meters. According to these watt meters the K2, set to full power of 110W, puts out about 80 - 85 W into a dummy load (SWR reads 1.1 on KAT100). Everything else seems to work very well, and manuals came with the radio. Any suggestions as to steps I should take to get full power output from the K2 (S/N 4000+), or is that close enough? __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] K2 Low power output
I recently acquired a very clean K2/100 with external KAT100 ATU. I have a K3/100 and its power output agrees closely with the readings of both Bird and Elecraft W2 watt meters. According to these watt meters the K2, set to full power of 110W, puts out about 80 - 85 W into a dummy load (SWR reads 1.1 on KAT100). Everything else seems to work very well, and manuals came with the radio. Any suggestions as to steps I should take to get full power output from the K2 (S/N 4000+), or is that close enough? Dave, W8OV __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Low Power on 12 and 10 Meters
Larry, Since you mentioned "a pot to adjust", what is the chance that you increased the value of R98 (on the bottom of the RF board) above its normal value of 270 ohms. That resistor is sometimes increased to provide more rapid settling time for the power control loop (particularly in TUNE), and the procedure to find the correct value is to temporarily substitute a pot. If the resistor value is too high, the power on 10 (and often 12) meters will drop. Remove the bottom cover to check R98. There is no pot to adjust other than the temporary one mentioned above. 73, Don W3FPR On 11/17/2013 12:02 PM, Larry Dodson wrote: In the past I have looked up various problem fixes in the Old Elecraft Digests, but can no longer find them? I would appreciate suggestion as to how I fix my K2 low power problem on 12 and 10 Meters. I think that there is a pot to adjust? Running the K2 without PA (ATU and Power Meter shows 1:1.1) into a dummy load. I find that all HF bands get a full 10-12 watts output, except 12 and 10 Meters, where I get 7 watts on 12M and less on 10M. This reduced output is reflected on the watt meter when I hook up my external KPA100/KAT100 and use more power. Help will be appreciated in solving the output problem and also where to find the Old Elecraft Digests. __ 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] K2 Low Power on 12 and 10 Meters
Larry, Take a look at http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_28.html#K2-tweak - second item - which talks about various tricks to do with the T2 and T1 transformers. Lifting T2 helped me. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-on-12-and-10-Meters-tp7580925p7580932.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] K2 Low Power on 12 and 10 Meters
In the past I have looked up various problem fixes in the Old Elecraft Digests, but can no longer find them? I would appreciate suggestion as to how I fix my K2 low power problem on 12 and 10 Meters. I think that there is a pot to adjust? Running the K2 without PA (ATU and Power Meter shows 1:1.1) into a dummy load. I find that all HF bands get a full 10-12 watts output, except 12 and 10 Meters, where I get 7 watts on 12M and less on 10M. This reduced output is reflected on the watt meter when I hook up my external KPA100/KAT100 and use more power. Help will be appreciated in solving the output problem and also where to find the Old Elecraft Digests. 73 - Larry- G0IKE (K2 -2424) __ 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] K2 Low Power Out / Hi Current
So, I have learned another lesson on paying attention to details. Seems the analog watt meter I was using is only rated as low as 20mhz, and the digital Rhode and Schwartz actually had a 200Mhz sensor on it. No wonder the readings were bad. I did go back to the analog meter on 15M, 12M, and 10M. At 10W on the radio I was showing 3.5W on the analog meter. It has a correction factor of +40% for 20Mhz, so that would be a reading of 5W, about half of what it should be. I did the signal tracing from the manual. Some values were considerably low, while other were quite close. Xmit mixer out read .002 vice .016 Buffer Output was .107 vice .200. Predriver Output .65 vice .120 Driver input .008 vice .026 -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570959.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] K2 Low Power Out / Hi Current
Jeremy, Strange problem. The K2 RF power detector consists of voltage divider R67 and R68 and diode D9. One end of R67 is connected directly to the BNC center conductor. That means your problem is quite a mystery. Could it be a bad coax or a faulty (or not soldered) BNC connector. The only other possibility I can think of is a broken PC trace, but those traces are quite large. If there is not a proper connection to the dummy load, the normal result is a HiCur message with the power set to a high level because the K2 is operating into an open circuit. 73, Don W3FPR On 3/7/2013 8:04 AM, JeremyJones wrote: Don, I suspected something might be wrong with the watt meter, as it was borrowed from work and had not been used in a while. I was able to listen to quite a few signals last night, however I wasn't able to make any contacts. I brought my radio into work and tested it on a Rhode and Schwartz FSH8 with power sensor to double check the original power meter and the radio. Even with the radio set to 10W I was showing no power out. I don't have the schematic handy, but can I do some signal tracing from between where the K2 takes its power reading and the BNC output? __ 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] K2 Low Power Out / Hi Current
Don, I suspected something might be wrong with the watt meter, as it was borrowed from work and had not been used in a while. I was able to listen to quite a few signals last night, however I wasn't able to make any contacts. I brought my radio into work and tested it on a Rhode and Schwartz FSH8 with power sensor to double check the original power meter and the radio. Even with the radio set to 10W I was showing no power out. I don't have the schematic handy, but can I do some signal tracing from between where the K2 takes its power reading and the BNC output? -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570930.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] K2 Low Power Out / Hi Current
Jeremy and all, the external wattmeter reading has to overcome the diode drop in the wattmeter before it will provide deflection. At low power levels it may show no response until the power is great enough for the diodes to conduct. The full scale reading of the wattmeter may be correct, but at low power levels there is a certain 'threshold' below which some meters will show no power output (regardless of the range). I am glad to hear that you now have the bandpass filters peaked. 73, Don W3FPR On 3/6/2013 5:17 PM, JeremyJones wrote: The watt meter has a 5, 15, 50, 100W ranges, and I was using the 15 and 5 to try and get measurements. Carrying on with calibration using the internal meter yielded the expected results. I may actually be able get this on the air tonight! Thanks for the help, Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570907.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] K2 Low Power Out / Hi Current
The watt meter has a 5, 15, 50, 100W ranges, and I was using the 15 and 5 to try and get measurements. Carrying on with calibration using the internal meter yielded the expected results. I may actually be able get this on the air tonight! Thanks for the help, Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570907.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] K2 Low Power Out / Hi Current
Jeremy, What range is your external wattmeter set for? If it is 100 watts or 200 watts, you will probably not get any deflection at 2.4 watts. When the load is 50+j0 ohms, you can rely on the K2 display. I suggest removing the external wattmeter and using the display. 73, Don W3FPR On 3/6/2013 3:55 PM, JeremyJones wrote: Looks like a bad coax was indeed causing the high current issue. I've resolved that, but I'm still show no power out on the external watt meter, while the internal is reading 2.4. Jeremy VA3ZTF __ 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] K2 Low Power Out / Hi Current
Looks like a bad coax was indeed causing the high current issue. I've resolved that, but I'm still show no power out on the external watt meter, while the internal is reading 2.4. Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570905.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] K2 Low Power Out / Hi Current
Jeremy, A high SWR will cause that behavior. Make certain the coax you are using is good. Remove it from the K2 end and check with an antenna analyzer if possible. If you cannot do that, look at the SWR registered on the wattmeter - if it is 1:1, remove the wattmeter and connect that coax to the dummy load (no wattmeter). 73, Don W3FPR On 3/5/2013 9:08 PM, JeremyJones wrote: Hi Don, The capacitors all look good, and I found one issue with a toroid and corrected it, but the issue remains. T4 is wound with proper number of turns, but wires do overlap some instead of being stacked neatly. Not sure if this could cause an issue or not. T4 is also standing off the board a bit, rather than being snug to the screws underneath. Jeremy VA3ZTF __ 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] K2 Low Power Out / Hi Current
Jeremy, T4 being off the board should not make any difference. Are you operating into a dummy load that is 50 ohms pure resistive, or are you operating into an antenna? The base K2 needs to operate into a 50 ohm resistive load for good power control and a proper impedance. If you are operating into an antenna, use your antenna analyzer and adjust your tuner for a 50 +/- j0 impedance. 73, Don W3FPR On 3/5/2013 9:08 PM, JeremyJones wrote: Hi Don, The capacitors all look good, and I found one issue with a toroid and corrected it, but the issue remains. T4 is wound with proper number of turns, but wires do overlap some instead of being stacked neatly. Not sure if this could cause an issue or not. T4 is also standing off the board a bit, rather than being snug to the screws underneath. Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570857.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] K2 Low Power Out / Hi Current
Hi Don, The capacitors all look good, and I found one issue with a toroid and corrected it, but the issue remains. T4 is wound with proper number of turns, but wires do overlap some instead of being stacked neatly. Not sure if this could cause an issue or not. T4 is also standing off the board a bit, rather than being snug to the screws underneath. Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850p7570857.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] K2 Low Power Out / Hi Current
Jeremy, The problem of HiCur coupled with low power output is usually associated with a problem either in T4 or the Low Pass Filter. Check all the capacitors in the Low Pass Filter for proper values and count the turns on the toroids. Count only the turns passing through the center of the core. It is easy to put an extra turn on the toroids, and the result is a HiCur message along with low power output. 73, Don W3FPR On 3/5/2013 7:58 PM, JeremyJones wrote: I'm trying to complete the stage 3 transmitter alignment on my K2 and have run into a bit of a snag. The 40M check looks good according to the built in power meter, however with an external watt meter connected to a dummy load, I am getting less than 1W on the with the K2 set at 2W, and about 2W when set for 10W. Moving on to 80M at 2W I get a high current warning. __ 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] K2 Low Power Out / Hi Current
I'm trying to complete the stage 3 transmitter alignment on my K2 and have run into a bit of a snag. The 40M check looks good according to the built in power meter, however with an external watt meter connected to a dummy load, I am getting less than 1W on the with the K2 set at 2W, and about 2W when set for 10W. Moving on to 80M at 2W I get a high current warning. I checked the voltages on Q5, Q6, Q7 and Q8 as per the manual trouble shooting. All of the collectors are at 15.12V, and all emitters and bases are at 0v. My transformers look like the diagrams and have the proper number of turns. What else should I be looking at? Thanks Jeremy VA3ZTF -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-Low-Power-Out-Hi-Current-tp7570850.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] K2 low power out on 20 meters
The K2 'low power on 20 meters' problem has been resolved by the replacement of the C21 cap. Elecraft customer service is beyond compare. Thank you. Wiley, KG4UPO -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-low-power-out-on-20-meters-tp7570332p7570554.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] K2 low power out on 20 meters
Wiley, I trust you are peaking the bandpass filters at the 1.5 to 2 watt level rather than at 12 watts. If you are trying at 12 watts, you may not see the peak because the power is already near the maximum. Check the values of C19, C20, C28 and C22. If those are all correct and well soldered, then the conclusion is that C21 is defective. If you find anything other than a C21 problem, you will have to re-peak 30 meters before peaking on 20. 73, Don W3FPR On 2/25/2013 8:57 AM, Wiley Kling wrote: I am building my 3rd Elecraft K series kit, this time a K2, my second. All has gone well. I am on page 80 of the manual, right column, 3rd step, "adjust C21 and C23 for maximum power output". Adjusting C21 does absolutely nothing. Regardless of a very slow 360 degree rotation, power out does not change, does not peak. C23 works normally and peaked as it should. I continued with all of the other steps, peaking the power on all of the other bands. Here are some facts: __ 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] K2 low power out on 20 meters
I am building my 3rd Elecraft K series kit, this time a K2, my second. All has gone well. I am on page 80 of the manual, right column, 3rd step, "adjust C21 and C23 for maximum power output". Adjusting C21 does absolutely nothing. Regardless of a very slow 360 degree rotation, power out does not change, does not peak. C23 works normally and peaked as it should. I continued with all of the other steps, peaking the power on all of the other bands. Here are some facts: 1. Into a 50 ohm dummy load with a power meter, K2 power setting of 12 watts, power out reads as follows: 80M = 12W; 40M = 12W; 30M = 10W; 20M = 2W; 17M = 11W; 15M = 11W; 12M = 11W; 10M = 8W. All appears fine to me except 20 meters. 2. I have checked for cold solder joints, etc. especially around C21, C23, C19, C20, L8. 3. The receiver "hears" very well on 20 meters. 4. Everything else about the radio seems just fine. I conclude that C21 is defective. Before I ask for a part replacement is there anything else I should do or check? I thank you in advance for your suggestions and help. Wiley, KG4UPO __ 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] K2 Low Power?
Mike, If resistor R50 is open, in most cases you will have very little (less than 1 watt) output. My best guess is that one of the PA transistors opened up when you encountered a very high SWR. When experimenting with antennas, it is best to keep the power down to one or two watts. When practicing CW, either turn the power all the way down or put it into CW Test (Hold the MODE button). Caution, CW Test is turned off if you power cycle the K2. You can do Transmit Signal Tracing at any power level, but the Expected values in the manual will not be what is listed unless the power is set to 5 watts AND the K2 is not capable of producing 5 watts. 73, Don W3FPR On 9/16/2011 4:49 PM, vicki glover wrote: > Hello all, > I don't think my K2 is developing normal output power. Been having some > complaints about not being heard well enough to copy, so I hooked it up to a > dummy load and caluculated that when set to call for 15 watts it is only > producting about 8.56 watts with a current draw of 2.06A with supply voltage > of 13.7volts. Even if I run the supply voltage up to 15 volts it is still > under 10 watts. When it is set to call for 10 watts the output is under 5 > watts. I have been using the TEST mode to practice CW with a paddle (am used > to a bug). Would this have damaged the rig. I checked the troubleshooting > section in the manual about low power, but what is too low before I should > start doing the signal tracing? I did see a Hi-Cur warning a couple of times > when experimenting with some antennas, could the resistor R-50 be open? Any > thoughts would be welcome. > 73 > __ 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] K2 Low Power?
Hello all, I don't think my K2 is developing normal output power. Been having some complaints about not being heard well enough to copy, so I hooked it up to a dummy load and caluculated that when set to call for 15 watts it is only producting about 8.56 watts with a current draw of 2.06A with supply voltage of 13.7volts. Even if I run the supply voltage up to 15 volts it is still under 10 watts. When it is set to call for 10 watts the output is under 5 watts. I have been using the TEST mode to practice CW with a paddle (am used to a bug). Would this have damaged the rig. I checked the troubleshooting section in the manual about low power, but what is too low before I should start doing the signal tracing? I did see a Hi-Cur warning a couple of times when experimenting with some antennas, could the resistor R-50 be open? Any thoughts would be welcome. 73 mike-KB3QJA __ 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] K2 low power
Let me know if the LPF turns are the problem. If not, I will have to ask you to use an RF Probe (or preferrably an oscilloscope) to make some comparative Signal Tracing reading between a band that works and one that does not. 73, Don W3FPR Conway Yee wrote: >> If the low power and high current are only on 160, 80, 40, 20, 15, and >> 10 meters, then check the number of turns on the Low Pass Filter >> toroids. >> > > It appears to be 80,40,10,12 only. 15 and 20 are OK. I am in the middle > of checking the turns. > > > __ 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] K2 low power
> If the low power and high current are only on 160, 80, 40, 20, 15, and > 10 meters, then check the number of turns on the Low Pass Filter > toroids. It appears to be 80,40,10,12 only. 15 and 20 are OK. I am in the middle of checking the turns. tnx. Conway Yee, N2JWQ __ 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] K2 low power
Conway, Does the same thing occur on all bands? If so, re-check the turns on T4 and be certain it is not mounted backwards - the 'links' go only from the front of the core to the back (each one goes through only one hole). If the low power and high current are only on 160, 80, 40, 20, 15, and 10 meters, then check the number of turns on the Low Pass Filter toroids. Count the number of times the wire passes through the center of the core. On a toroid, a straight wire through the center is one turn, a complete wrap around the core id two turns. There are a few other possibilities, but they are less frequent and more obscure than the ones I have mentioned. If you feel Q6 is too warm, increase the value of R46 to 330 ohms (you could do that arbitrarily and it will cause no problem). 73, Don W3FPR Conway Yee wrote: > I have found low power on initial transmitter tests of my K2 construction. > I am unable to get above about 1 Watt before I get High Current. > > I can not find any obvious error in winding T1-4. I reflowed all the > joints involved in the toroids. > > Q6 is warm. I am unable to assess the temperature of Q7 or Q8 because of > the heatsink. > > No errors noted in the resistors in measuring power output. > > tnx. > Conway Yee, N2JWQ > > __ 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] K2 low power
I have found low power on initial transmitter tests of my K2 construction. I am unable to get above about 1 Watt before I get High Current. I can not find any obvious error in winding T1-4. I reflowed all the joints involved in the toroids. Q6 is warm. I am unable to assess the temperature of Q7 or Q8 because of the heatsink. No errors noted in the resistors in measuring power output. tnx. Conway Yee, N2JWQ __ 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] K2: Low power out on 12M & 10M
K2 # 6254 Only abt 1W out on 12M, 5W out on 10M. Worked FB when I assembled it last fall. I've been all over the 12/10M bandpass components with fresh solder. I went through TX alignment & found 20/17/15/12/10 all improved - but only ended up with the above power levels for 12/10. I have not compared voltages band-to-band at the bandpass output yet, will drag out the scope tomorrow. Then I'll look at the 12/10 LP filter area. Any other quick-hitters I should look at before I pull the bottom rear cover? Thanks! 73, Bill N2BC ___ 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] K2 Low Power 160m & 20m up
Hi to everyone on the list and a happy new year to all I put a request for help up unto the list before Christmas. I had an issue with the TX on the higher bands. On 20m and above the power dropped off considerable. I had a couple of emails and have now had a chance to check out the suggestion made. I have been doing some more testing. I checked C150 but its ok The setup is a K2 Serial 0413 with the following options fitted KSB2 K160RX KNB2 KAF2 K60VX KPA100 Although the issue appeared when I had the KPA installed I removed the KPA100 and the issue is still there. The issue is with the base radio. I have also removed the K60VX and KSB2 to put it back to a CW only radio and the issue persists except the on low power I am now getting very little out on 160m but 80 through 30 is at about 8 to 10 watts which is down as I used to get about which was about 15 watts out. I have had a good read of the previous posts and have done some more testing and my results are shown below. Band RF out TX Current In Amps Note 160 4.5 3 sometimes going hi-cur 80 8 2.9 60 9 2.8 40 9 2.54 30 10 2.6 20 5 2.02 17 4.5 1.9 15 4 1.78 12 3.5 1.62 10 3 1.44 I have also had a look at the control board and found that U8 pin 10 is always at +5volts and pin 11 is at 0v at switch on but when I go to TX it goes to +5volts and stays there on RX until I change band when it returns to 0volts. I have also had a look at the PA transistors. Q8 gets much hotter on TX. In fact there is very little change in the temp of Q7 compared to Q8. Could anyone suguest where to go next. Regards George GI4SJQ ___ 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] K2 - Low Power - T1 put in wrong
PK, Yes, T1 could explain the problems that you encountered. Correct T1 and then see how it behaves. Yes, there could be another problem, but that remains to be seen after T1 is corrected. 73, Don W3FPR Paul K wrote: I was helping my friend debug his K2 #3920. It is the qrp version and will put out up to 4W no matter how the power knob is turned. So if you want less than 4W, the power was as specified. When we turned the knob to increase the power grater than 4W, the power would stay at 4W. The K2 also indicated that only 4W were going out. The output power was measured with a W1 and attached to a dummy load (measured 50 ohm). We started trouble shooting as in the manual and we found that T1 had two problems. The first is that there was one extra secondary winding (green wire). The second problem was that the green wire was installed into #1 and #2 and the red wires were put into #3 and #4. We are obviously going to fix both of these problems. We did check T2, T3, and T4 and they seem to be correct. We are not engineers, so our question is, could T1 explain these symptoms, or should we keep looking for other things? 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] K2 - Low Power - T1 put in wrong
I was helping my friend debug his K2 #3920. It is the qrp version and will put out up to 4W no matter how the power knob is turned. So if you want less than 4W, the power was as specified. When we turned the knob to increase the power grater than 4W, the power would stay at 4W. The K2 also indicated that only 4W were going out. The output power was measured with a W1 and attached to a dummy load (measured 50 ohm). We started trouble shooting as in the manual and we found that T1 had two problems. The first is that there was one extra secondary winding (green wire). The second problem was that the green wire was installed into #1 and #2 and the red wires were put into #3 and #4. We are obviously going to fix both of these problems. We did check T2, T3, and T4 and they seem to be correct. We are not engineers, so our question is, could T1 explain these symptoms, or should we keep looking for other things? Thanks :) PK (Paul - K3MZ K2 #3135 K3 #xxx) ___ 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] K2 low power and HI current
John, Those two capacitors would cause you to have trouble getting a signal through the bandpass on 80 and on 40 meters. Yes, 56pf is labeled 560 and 560pf is labeled 561 - 82pf is labeled 820 while 820pf is labeled 821. Since you installed the incorrect capacitors in C12 and C4, the further part of the mystery must be 'where are the 560pf and 820pf capacitors installed?' - these may cause further trouble unless located and changed to the correct values. The parts list can be a valuable guide in checking where each value capacitor should be located. 73, Don W3FPR > -Original Message- > > The saga continues. > I am in the middle of building my very first breadboard project: a 10 > MHz oscillator to test the K2. Got about half of the parts from > Radio Shack. Got the XTAL and a few other parts at Hosfelt Electronics. > > For the Don, > I found two caps that were wrong in the bandpass area: > C12 was labelled 560 and should be 561 and > C4 was labelled 820 and should be 821 > > These appear to be order of magnitude differences so I HOPE their > correction leads me on. > > I remember correcting myself during the build : 560 is 561 ... 820 > is 821. > > Can Someone (I don't know who...could it be DON?!) confirm that the > above is correct and makes sense? > > If so, I'll order more caps. > > Thanks again for all the help > (and everyone's patience with what is becoming a record-breaking thread) > > John > AB8WH > ___ 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] K2 low power and HI current
The saga continues. I am in the middle of building my very first breadboard project: a 10 MHz oscillator to test the K2. Got about half of the parts from Radio Shack. Got the XTAL and a few other parts at Hosfelt Electronics. For the Don, I found two caps that were wrong in the bandpass area: C12 was labelled 560 and should be 561 and C4 was labelled 820 and should be 821 These appear to be order of magnitude differences so I HOPE their correction leads me on. I remember correcting myself during the build : 560 is 561 ... 820 is 821. Can Someone (I don't know who...could it be DON?!) confirm that the above is correct and makes sense? If so, I'll order more caps. Thanks again for all the help (and everyone's patience with what is becoming a record-breaking thread) John AB8WH ___ 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] K2 - low power on 160m?
Glenn, The most likely reason you did not get a response is that none of us have a good immediate answer. I suggest that you look at the RF voltages at the collector and base of Q5, Q6 and Q7/Q8 to determine where the problem is located. You can use a 'scope or an RF Probe to check the RF voltage levels (if using an RF probe, do not measure the collectors of Q7/Q8, you may zap the diode). Compare the readings obtained on 80 meters with those obtained on 160 meters. What you are looking for is a stage that has lower gain on 160 meters, so the measurements may be a bit more complex than a simple comparison - the K2 power output control may try to push the RF voltages on 160 higher trying to produce more output - so do the comparisons at a power level that your K2 is capable of delivering on 160 meters (the 2 or 3 watt level should do fine). 73, Don W3FPR > -Original Message- > Dear all > > I tried to send this question to the reflector yesterday but I > haven't got any responses so maybe the message did not make it > onto the reflector. One more try... > > I finished building K2 s/n 5361 Tuesday and managed to align it > on all bands 80-10m per the specs in the manual. > First tests (RX only) showed a wonderfully quiet receiver with > "good ears". TX is well within specs, up to 15W power out. > Encouraged by the FB results I started constructing the 160m > extension yesterday. No worries during assembly as far as I could see. > Then, after having installed the 160m PCB into the K2 I started > the alignment procedure.With 2W out all was OK both on 160 and > 80m, no problems peaking output power to about 2,5W. However, > when I try to crank the output power up to 10W as per the > instructions on p9 of the installation manual, I am unable to get > more than 6W output on 160m. 80m is OK (up to 16W output). > I have tried the alternative frequencies for peaking. 2W out is > OK all the time, but I get no more than 6W when I should be > reading 10W out. Cal Cur is set at 3.50A. Checked all solder > joints, toroid winding numbers, what have you. > > ___ 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] K2 - low power on 160m?
Dear all I tried to send this question to the reflector yesterday but I haven't got any responses so maybe the message did not make it onto the reflector. One more try... I finished building K2 s/n 5361 Tuesday and managed to align it on all bands 80-10m per the specs in the manual. First tests (RX only) showed a wonderfully quiet receiver with "good ears". TX is well within specs, up to 15W power out. Encouraged by the FB results I started constructing the 160m extension yesterday. No worries during assembly as far as I could see. Then, after having installed the 160m PCB into the K2 I started the alignment procedure.With 2W out all was OK both on 160 and 80m, no problems peaking output power to about 2,5W. However, when I try to crank the output power up to 10W as per the instructions on p9 of the installation manual, I am unable to get more than 6W output on 160m. 80m is OK (up to 16W output). I have tried the alternative frequencies for peaking. 2W out is OK all the time, but I get no more than 6W when I should be reading 10W out. Cal Cur is set at 3.50A. Checked all solder joints, toroid winding numbers, what have you. Today I did a few additional checks. DC resistance across the two toroids L1/L2 in series (measured between pins 9 and 14 on J1) is OK, very close to 0 ohms. DC resistance between the toroid sides of C1 and C3 is also about 0 ohms. With 2W out on 1840 kHz (where I did the peaking of L3/4) I get 1,5W on 1810 and 2,2W on 1900 kHz. C68 is 10pF, C153 is 68pF, C75 470pF and C13/14 are 1200 pF. I did notice that the voltage and current readings during tx on 160m are not very stable, the readings change continuously. I listed the min and max values for E and I for a number of output power levels below: P=0,1W: E=13,9/14,0 I=0,58/0,62 P=1W: E=13,6/13/9 I=0,88/0,96 P=2W: E=13,5/13/9 I=1,08/1,14 P=5W: E=13,2/13,8 I=1,54/1,64 P=6W (Power pot at max position): E=13,1/13,8 I=1,70/1,82 I checked on other bands but this phenomenon only occurs on 160m. Where should I look? I'm fairly confident that the problem should be located somewhere in the 160m LPF as there is no sign of any problems on any other band. I checked the forum archives for clues. I did find an article pointing to the capacitor values mentioned earlier but I've got the correct values installed. Any ideas? Tnx for your help. 73 de ON4WIX Glenn ___ 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] K2 low power and SWR problems
Christer, If your antenna tuner is indeed properly matched on the band you want to operate and gives a high VSWR using the K2, that tells you the K2 is delivering power on another frequency. This happens if the transmitter is on the wrong band (probably not your problem) OR if the transmitter has high harmonic output. This is most likely your problem. The K2 might have high harmonic output if one or more of the output low-pass filter relays is not switching correctly. My guess based on your information is that one of the output filter relays (K8 through K12) is stuck in the closed position. This leaves one set of filter components in line all the time, allowing harmonic content to pass through the filter and into the tuner. The tuner, when tuned for example to 80M, indicates a high VSWR because it is also seeing power at 40M or 15M or whatever frequency. If only one relay is stuck closed, that band should NOT show this problem. Thus, if you tune your antenna tuner to each band and try it, you may find one band that works OK. This band is the one with the stuck relay. The reason you can tune OK into the dummy load is because the dummy load is not frequency selective and provides the proper match regardless of harmonic content. This is a key piece of information. So .. you have harmonic output. A likely cause is a stuck relay, but in general you should be looking for problems around the transmit low pass filter. I think you will find your problem there. Good luck and I hope you are successful in tracking down this problem. Best Regards, Jim, AB4CZ K2 s/n 5230 (brand new Christmas present ! ) -- Original message -- From: "Christer Karlsson" <[EMAIL PROTECTED]> > I built my K2 in late 1999 and it has behaved the same way ever since. > Gary has been very helpful and once his advice was correct (bad soldered > antenna connection) but it did not improve my K2. I did not want to > bother Elecraft anymore so I have learned to live with my rig. However > now I have decided to do something to cure my K2. > > When I change band I first have to tune into a 50 ohm dummy load before > I switch to the antenna. If I first connect K2 to my antenna tuner > (perfect match) the power is significantly reduced and my cross needle > SWR meter shows high SWR. > > If I have tuned via dummy load, then connected to the ATU (with good > match) and start reducing output from K2 the SWR meter will show a great > mismatch when having decreased to about 2 watts. The "low power > hostility" is most outspoken on 80 m. > > This I guess is also why I can not use K2 on SSB. > > > > Chris, SM7KJH > > > > > ___ > 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] K2 low power and SWR problems
Chris, That is very strange, but if the K2 operates properly into a dummy load, but not into the tuner, then the problem is not in the K2, but either in the tuner or in the coax between the K2 and the tuner. If your tuner is adjusted for a perfect match, that alone tells us that it should be exactly a 50 ohm non-reactive load - just the same as your dummy load. How are you determining that your tuner is set to a 'perfect match'? The only other reason that I can think of is that you may have a significant amount of RF in the shack if the RF return path is different when you have the K2 connected to the tuner input vs. the RF return path created when you use the device (whatever instrument) that indicates your tuner is adjusted for a perfect match. If you are not using a balanced antenna, this is quite likely. You may wish to experiment with some quarterwavelength counterpoise wires. 73, Don W3FPR > -Original Message- > > I built my K2 in late 1999 and it has behaved the same way ever since. > Gary has been very helpful and once his advice was correct (bad soldered > antenna connection) but it did not improve my K2. I did not want to > bother Elecraft anymore so I have learned to live with my rig. However > now I have decided to do something to cure my K2. > > When I change band I first have to tune into a 50 ohm dummy load before > I switch to the antenna. If I first connect K2 to my antenna tuner > (perfect match) the power is significantly reduced and my cross needle > SWR meter shows high SWR. > > If I have tuned via dummy load, then connected to the ATU (with good > match) and start reducing output from K2 the SWR meter will show a great > mismatch when having decreased to about 2 watts. The "low power > hostility" is most outspoken on 80 m. > > This I guess is also why I can not use K2 on SSB. > > Chris, SM7KJH > ___ 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] K2 low power and SWR problems
I built my K2 in late 1999 and it has behaved the same way ever since. Gary has been very helpful and once his advice was correct (bad soldered antenna connection) but it did not improve my K2. I did not want to bother Elecraft anymore so I have learned to live with my rig. However now I have decided to do something to cure my K2. When I change band I first have to tune into a 50 ohm dummy load before I switch to the antenna. If I first connect K2 to my antenna tuner (perfect match) the power is significantly reduced and my cross needle SWR meter shows high SWR. If I have tuned via dummy load, then connected to the ATU (with good match) and start reducing output from K2 the SWR meter will show a great mismatch when having decreased to about 2 watts. The "low power hostility" is most outspoken on 80 m. This I guess is also why I can not use K2 on SSB. Chris, SM7KJH ___ 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
