Re: [Elecraft] K3 Internal Tuner Question
Well here's one for you: My setup is K3 to wattmeter to dummy load. The K3 says 100w If the external wattmeter is: MFJ 949E tuner/SWR meter (tuner out of circuit) it says 100w cheapo Radio Shack SWR meter 100w LP 100A digital wattmeter says 70 watts Elecraft W2 says 70 watts Yes, I have run the transmitter calibration routine in the K3 Utility program. SWR in all three cases is nominal 1:1 The result is the same to a real antenna although the SWR is not 1:1 What could be causing the external-sensor type wattmeters to read low? Buck k4ia K3 # 101 On 1/2/2012 10:14 PM, Ron D'Eau Claire wrote: Quite right. There a couple of impedance transformations that occur between the collectors (or plates) of the power amplifiers and the antenna. The first is done by the output filters. In modern rigs, they are fixed tuned and designed in common Ham rigs to convert the impedance at the collectors to 50 ohms, resistive. If your antenna presents that impedance, no further conversion is necessary. But many antennas don't. In the old days the output network was adjustable and we simply did the necessary adjustments and all was good. Nowadays, with fixed tuned amplifier output networks, we need another matching network to handle the conversion when the antenna doesn't present a 50 ohms resistive load. Enter the antenna tuner that converts what the antenna shows to the 50 ohms needed by the output filter. The built in SWR meter displays the SWR on the link between the tuner and the output filter. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Tom Azlin N4ZPT Sent: Monday, January 02, 2012 6:19 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Internal Tuner Question Thanks Matthew. I should not have spoken like that. Should just have said the meter in the line would not change just because a radio tuner transformed impedance to make the radio happy. 73, tom n4zpt On 1/2/2012 9:11 PM, Matthew Pitts wrote: Tom, All an antenna tuner does is show the radio the load it expects; the SWR will still be high at the output of the tuner, and an SWR meter in the coax at that output will show it as it actually is at that point, not as it is on the input of the tuner/output of the radio. Matthew Pitts N8OHU __ 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] K3 Internal Tuner Question
Buck, You are like the man with 2 (or more) watches who never knew what time it was! Was your LP-100A calibrated to NIST traceable standards (Larry's calibration tools)? If the answer is yes, I would use the LP-100A as the standard to calibrate the K3 wattmeter (see instructions in the manual). After having calibrated the internal wattmeter in the K3, then run the TX gain calibration with K3 Utility. 73, Don W3FPR On 1/3/2012 8:50 AM, Buck k4ia wrote: Well here's one for you: My setup is K3 to wattmeter to dummy load. The K3 says 100w If the external wattmeter is: MFJ 949E tuner/SWR meter (tuner out of circuit) it says 100w cheapo Radio Shack SWR meter 100w LP 100A digital wattmeter says 70 watts Elecraft W2 says 70 watts Yes, I have run the transmitter calibration routine in the K3 Utility program. SWR in all three cases is nominal 1:1 The result is the same to a real antenna although the SWR is not 1:1 What could be causing the external-sensor type wattmeters to read low? Buck k4ia K3 # 101 On 1/2/2012 10:14 PM, Ron D'Eau Claire wrote: Quite right. There a couple of impedance transformations that occur between the collectors (or plates) of the power amplifiers and the antenna. The first is done by the output filters. In modern rigs, they are fixed tuned and designed in common Ham rigs to convert the impedance at the collectors to 50 ohms, resistive. If your antenna presents that impedance, no further conversion is necessary. But many antennas don't. In the old days the output network was adjustable and we simply did the necessary adjustments and all was good. Nowadays, with fixed tuned amplifier output networks, we need another matching network to handle the conversion when the antenna doesn't present a 50 ohms resistive load. Enter the antenna tuner that converts what the antenna shows to the 50 ohms needed by the output filter. The built in SWR meter displays the SWR on the link between the tuner and the output filter. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Tom Azlin N4ZPT Sent: Monday, January 02, 2012 6:19 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Internal Tuner Question Thanks Matthew. I should not have spoken like that. Should just have said the meter in the line would not change just because a radio tuner transformed impedance to make the radio happy. 73, tom n4zpt On 1/2/2012 9:11 PM, Matthew Pitts wrote: Tom, All an antenna tuner does is show the radio the load it expects; the SWR will still be high at the output of the tuner, and an SWR meter in the coax at that output will show it as it actually is at that point, not as it is on the input of the tuner/output of the radio. Matthew Pitts N8OHU __ 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 __ 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] K3 Internal Tuner Question
John, I'm not being flippant. Please pick up a copy of Reflections III by Walt Maxwell W2DU, published by CQ Comuunications. The book covers a lot of ground and will deepen your understanding of what you are rightly seeing. 73, de Nate N0NB -- The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true. Ham radio, Linux, bikes, and more: http://www.n0nb.us __ 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] K3 Internal Tuner Question
John I would struggle to explain this, but I'm quite certain that what you are seeing is quite correct and nothing to worry about. The Palstar is showing you the swr of the antenna and feedline. The K3 ATU is matching the transmitter to this impedance. The ATU does not change the antenna impedance. Regards John G4ZTR -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Dziedziejko Sent: 02 January 2012 04:13 To: elecraft@mailman.qth.net Subject: [Elecraft] K3 Internal Tuner Question I installed the KAT3 over the weekend and the construction and calibration was successful. This evening I hooked everything back up to check reception, tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a Palstar Wattmeter installed between the K3 and the antenna and for some reason I am getting a high swr on the Palstar meter of 5:1 and don't understand why. I have a multiband vertical antenna with a 4:1 Unun at the base of the antenna. Am I missing something here? A little hand holding would be appreciated. Regards, John W9QP __ 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 __ Information from ESET NOD32 Antivirus, version of virus signature database 6759 (20120101) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 6761 (20120102) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.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] K3 Internal Tuner Question
John, that is a common question. The KAT3 is providing a 1:1 SWR between the KAT3 and the PA *inside* the K3 so the K3's PA is 'seeing' the correct load. The KAT3 cannot change the impedance of the antenna presented to the ANT connector. You didn't say how much coax ran from the K3 to the Palstar. For an accurate comparison it should be zero (use an adapter) or at most an couple of inches of coax. You can replace the antenna with a good dummy load, and they should read much closer, although most dummy loads have some error as well, nor are SWR meters precision instruments; they don't need to be for efficient transmission line operation at H.F. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Dziedziejko Sent: 02 January 2012 04:13 To: elecraft@mailman.qth.net Subject: [Elecraft] K3 Internal Tuner Question I installed the KAT3 over the weekend and the construction and calibration was successful. This evening I hooked everything back up to check reception, tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a Palstar Wattmeter installed between the K3 and the antenna and for some reason I am getting a high swr on the Palstar meter of 5:1 and don't understand why. I have a multiband vertical antenna with a 4:1 Unun at the base of the antenna. Am I missing something here? A little hand holding would be appreciated. Regards, John W9QP __ 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 __ Information from ESET NOD32 Antivirus, version of virus signature database 6759 (20120101) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 6761 (20120102) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.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] K3 Internal Tuner Question
You didn't say how much coax ran from the K3 to the Palstar. For an accurate comparison it should be zero (use an adapter) or at most an couple of inches of coax. It the KAT3 is in use one can *never* compare the SWR displayed by the K3 and that displayed by an external SWR bridge/wattmeter since there will be an *impedance changing device* (the KAT3) between the K3's SWR detector and the external SWR detector even if the length of coax is zero. 73, ... Joe, W4TV On 1/2/2012 11:27 AM, Ron D'Eau Claire wrote: John, that is a common question. The KAT3 is providing a 1:1 SWR between the KAT3 and the PA *inside* the K3 so the K3's PA is 'seeing' the correct load. The KAT3 cannot change the impedance of the antenna presented to the ANT connector. You didn't say how much coax ran from the K3 to the Palstar. For an accurate comparison it should be zero (use an adapter) or at most an couple of inches of coax. You can replace the antenna with a good dummy load, and they should read much closer, although most dummy loads have some error as well, nor are SWR meters precision instruments; they don't need to be for efficient transmission line operation at H.F. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Dziedziejko Sent: 02 January 2012 04:13 To: elecraft@mailman.qth.net Subject: [Elecraft] K3 Internal Tuner Question I installed the KAT3 over the weekend and the construction and calibration was successful. This evening I hooked everything back up to check reception, tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a Palstar Wattmeter installed between the K3 and the antenna and for some reason I am getting a high swr on the Palstar meter of 5:1 and don't understand why. I have a multiband vertical antenna with a 4:1 Unun at the base of the antenna. Am I missing something here? A little hand holding would be appreciated. Regards, John W9QP __ 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 __ Information from ESET NOD32 Antivirus, version of virus signature database 6759 (20120101) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 6761 (20120102) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.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 __ 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] K3 Internal Tuner Question
John, No harm to leave the external meter in line, just don't use it's readings.. I have a Palstar ATU in line for when I use my amp with my multi-band doublet. When the amp is not switched in I'll often bypass the ATU and use the KAT3. The swr meter in the Palstar atu is still in-line however and will indicate forward and reflected powers consistent with whatever swr is on the line between the KAT3 and antenna; the swr reading on the K3 is all that matters in this case but the external meter is not doing any harm 73, Stewart, GW0ETF John Dziedziejko wrote Thanks for the responses, will take the Palstar out and hook the antenna directly to the K3 and go by the K3's swr meter and power output indications. Best regards, John W9QP __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@.qth This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Internal-Tuner-Question-tp7143059p7144340.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] K3 Internal Tuner Question
Quite right Joe, since, as I said, the KAT3 is providing a low SWR between the KAT3 and PA *inside* the K3. Now for another cup of coffee... Ron AC7AC -Original Message- You didn't say how much coax ran from the K3 to the Palstar. For an accurate comparison it should be zero (use an adapter) or at most an couple of inches of coax. It the KAT3 is in use one can *never* compare the SWR displayed by the K3 and that displayed by an external SWR bridge/wattmeter since there will be an *impedance changing device* (the KAT3) between the K3's SWR detector and the external SWR detector even if the length of coax is zero. 73, ... Joe, W4TV __ 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] K3 Internal Tuner Question
I also have a meter between my K3 and my antenna. The AWESOME tuner in the K3 keeps the radio happy, while the external meter will show, at a glance if there has been any significant change in the antenna itself. Dave - K9FN Sent from my Samsung smartphone on ATT GW0ETF gw0...@btinternet.com wrote: John, No harm to leave the external meter in line, just don't use it's readings.. I have a Palstar ATU in line for when I use my amp with my multi-band doublet. When the amp is not switched in I'll often bypass the ATU and use the KAT3. The swr meter in the Palstar atu is still in-line however and will indicate forward and reflected powers consistent with whatever swr is on the line between the KAT3 and antenna; the swr reading on the K3 is all that matters in this case but the external meter is not doing any harm 73, Stewart, GW0ETF John Dziedziejko wrote Thanks for the responses, will take the Palstar out and hook the antenna directly to the K3 and go by the K3's swr meter and power output indications. Best regards, John W9QP __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@.qth This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Internal-Tuner-Question-tp7143059p7144340.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] K3 Internal Tuner Question
John, The VSWR will still be the same as you read on Palstar. What you are seeing on the K3 is the VSWR being presented to the K3 PA stage. It's not the actual VSWR on the system as a whole. That VSWR is what the Palstar is seeing. Barry KS7DX -Original Message- From: John Dziedziejko [mailto:dziedziej...@bellsouth.net] Sent: Sunday, January 01, 2012 8:37 PM To: elecraft@mailman.qth.net Subject: [Elecraft] K3 Internal Tuner Question Thanks for the responses, will take the Palstar out and hook the antenna directly to the K3 and go by the K3's swr meter and power output indications. Best regards, John W9QP __ 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] K3 Internal Tuner Question
Let me see if I can correctly state, with clarity for all to understand so this thread can die peacefully and we can move on (please?). The K3 puts out power into an internal tuner (if installed) and then to an SO-239 at the rear of the radio. If the tuner is in bypass, the impedance is very close to 50 ohm resistive at that connector. In this case, any SWR meter (bridge) downstream to the antenna will read the SWR (AT THAT POINT IN THE FEEDLINE which may/not agree with the K3 reading). If the tuner is NOT in bypass, the impedance at the same SO-239 will be +-10:1 of 50 ohms. Since any other SWR meter (bridge) between the K3 and the antenna is probably NOT seeing the expected 50 Ohm impedance, the reading of OTHER than the K3 meter will be called into question and more than likely wrong. Repeating, when the internal tuner is used, the K3 meter is the only one that is accurate. Thank you and Happy New Year, Rick wa6nhc __ 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] K3 Internal Tuner Question
Rick, Not quite -- Both SWR meters can be quite accurate - they are just not measuring the same thing. Imagine an external tuner - put an SWR meter on the input, and another on the output - Now make changes to the L and C in the tuner - note that the SWR meter on the input is the only one that will change - the one on the output will stay at the same SWR indication. The Antenna Tuner does not change anything in the antenna system beyond the tuner output - (yes, it is not very well named) - what an antenna tuner does is add inductance and capacity at one point in the feedline so that the impedance at its input is close to 50 ohms resistive. It transforms the impedance -- it really does not Tune anything. The same thing happens with the internal tuner in the K3 - the K3 indicates the same as the meter on the *input* in my example above - the external meter acts as the one on the output, and it will not change no matter how you change the settings of the ATU. 73, Don W3FPR On 1/2/2012 8:06 PM, Rick Bates wrote: Let me see if I can correctly state, with clarity for all to understand so this thread can die peacefully and we can move on (please?). The K3 puts out power into an internal tuner (if installed) and then to an SO-239 at the rear of the radio. If the tuner is in bypass, the impedance is very close to 50 ohm resistive at that connector. In this case, any SWR meter (bridge) downstream to the antenna will read the SWR (AT THAT POINT IN THE FEEDLINE which may/not agree with the K3 reading). If the tuner is NOT in bypass, the impedance at the same SO-239 will be +-10:1 of 50 ohms. Since any other SWR meter (bridge) between the K3 and the antenna is probably NOT seeing the expected 50 Ohm impedance, the reading of OTHER than the K3 meter will be called into question and more than likely wrong. Repeating, when the internal tuner is used, the K3 meter is the only one that is accurate. __ 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] K3 Internal Tuner Question
Not sure I understand this. I did not think an SWR meter was supposed to work properly only when seeing 50 ohms restive. If the line is not flat it is terminated in to something other than the feedline impedance, i.e. not 50 ohms restive in this discussion. I would expect the SWR meter at some point in the feedline to be accurate under those conditions because it is supposed to measure the standing wave ratio of the feedline with respect to that 50 ohm resistive. If I then have an antenna coupler in the radio that is matching the transmitter to that non-50 ohm impedance why would the SWR meter change to inaccurately measuring the SWR? Putting the K3 into bypass or letting it tune should not change the SWR measures at some point in the feedline. The K3 may show 1:1 simply because it properly transformed the line impedance to 50 ohms restive. Perhaps I am missing something here. Sorry for continuing the discussion. 73, tom n4zpt On 1/2/2012 8:06 PM, Rick Bates wrote: Let me see if I can correctly state, with clarity for all to understand so this thread can die peacefully and we can move on (please?). The K3 puts out power into an internal tuner (if installed) and then to an SO-239 at the rear of the radio. If the tuner is in bypass, the impedance is very close to 50 ohm resistive at that connector. In this case, any SWR meter (bridge) downstream to the antenna will read the SWR (AT THAT POINT IN THE FEEDLINE which may/not agree with the K3 reading). If the tuner is NOT in bypass, the impedance at the same SO-239 will be +-10:1 of 50 ohms. Since any other SWR meter (bridge) between the K3 and the antenna is probably NOT seeing the expected 50 Ohm impedance, the reading of OTHER than the K3 meter will be called into question and more than likely wrong. Repeating, when the internal tuner is used, the K3 meter is the only one that is accurate. Thank you and Happy New Year, Rick wa6nhc __ 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] K3 Internal Tuner Question
Tom, All an antenna tuner does is show the radio the load it expects; the SWR will still be high at the output of the tuner, and an SWR meter in the coax at that output will show it as it actually is at that point, not as it is on the input of the tuner/output of the radio. Matthew Pitts N8OHU Sent from my Wireless Device __ 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] K3 Internal Tuner Question
Thanks Matthew. I should not have spoken like that. Should just have said the meter in the line would not change just because a radio tuner transformed impedance to make the radio happy. 73, tom n4zpt On 1/2/2012 9:11 PM, Matthew Pitts wrote: Tom, All an antenna tuner does is show the radio the load it expects; the SWR will still be high at the output of the tuner, and an SWR meter in the coax at that output will show it as it actually is at that point, not as it is on the input of the tuner/output of the radio. Matthew Pitts N8OHU __ 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] K3 Internal Tuner Question
Quite right. There a couple of impedance transformations that occur between the collectors (or plates) of the power amplifiers and the antenna. The first is done by the output filters. In modern rigs, they are fixed tuned and designed in common Ham rigs to convert the impedance at the collectors to 50 ohms, resistive. If your antenna presents that impedance, no further conversion is necessary. But many antennas don't. In the old days the output network was adjustable and we simply did the necessary adjustments and all was good. Nowadays, with fixed tuned amplifier output networks, we need another matching network to handle the conversion when the antenna doesn't present a 50 ohms resistive load. Enter the antenna tuner that converts what the antenna shows to the 50 ohms needed by the output filter. The built in SWR meter displays the SWR on the link between the tuner and the output filter. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Tom Azlin N4ZPT Sent: Monday, January 02, 2012 6:19 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Internal Tuner Question Thanks Matthew. I should not have spoken like that. Should just have said the meter in the line would not change just because a radio tuner transformed impedance to make the radio happy. 73, tom n4zpt On 1/2/2012 9:11 PM, Matthew Pitts wrote: Tom, All an antenna tuner does is show the radio the load it expects; the SWR will still be high at the output of the tuner, and an SWR meter in the coax at that output will show it as it actually is at that point, not as it is on the input of the tuner/output of the radio. Matthew Pitts N8OHU __ 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] K3 Internal Tuner Question
Hi Tom, Ok, one more swing at it. The tuner as Don states (and we agree), is transforming the 50 Ohm impedance of the transmitter, into something that mates better with the impedance of the antenna for (hopefully*) better transfer of energy to/from the antenna. There are similar circuits inside every radio to transfer the energy between sections. The proper term would be impedance matching circuit or device but we're taught (and stuck with) 'tuner'. Now, using our beloved K3 in this example: Tuner in bypass produces ~50 Ohm impedance at the back of the K3. Tuner in use produces an impedance of somewhere between 5-500 Ohms at the back of the same K3. You don't know what that impedance is. The SWR meter is expecting (because transmitters are usually set to) 50 Ohm impedance. If that impedance is off, the meter reading is probably wrong. Sure, it will read something, but the reading is worthless (even as a power meter) because of the mismatch. The amount of error is dependent on the amount of mismatch (which we don't know). So you're correct, that they are only accurate at 50 Ohm impedance (give or take a small percentage). This is why you put the SWR meter between the output of a known impedance (50 Ohm coming out of the transmitter) and the matching device (50 Ohm input). As the device changes LC values to compensate for (match) the reactance(s) of the antenna, the standing wave at the meter is reduced. This is how you can tell that the matching device is transferring more energy to the antenna (the reactance is 'tuned' out). As Don also accurately stated, it doesn't make the antenna work ANY better, but it does transfer more energy TO the antenna (disregarding tuner and line losses) because of better matching. And note that I most carefully said that the meter makes a reading AT THAT POINT IN THE FEEDLINE. If you add/subtract patch cables to an external meter (or alter feedline length), your reading may very well be different. The 'trap' that many hams fall into is that the feedline is treated as a 'hose' between transmitter and antenna. It isn't; but is PART of the entire circuit (it is not passive). Which leads to your next comment. What you were referring to was that the impedance of the antenna is best read (is duplicated) at half wave intervals on the feedline (ignoring the added feedline reactance). Most hams simply cut to convenient lengths (me too) because we're using multiple band antennas (or at least feeding them that way) and we tend to let the 'tuner' take up any slack (or ignore the losses). This is why the K3 meter, sensing at the transmitter output and before the internal tuner, is the best place to measure SWR. The tuner matches THAT point in the feedline system for best transfer of energy. The bottom line is simple. If you are using a matching device (a tuner) the ONLY place that a SWR meter will accurately read what you expect, is after the amplifier and before the matching device. This should also show you why short patch cables should be used to attach the SWR meter to the transmitter, to minimize error from reading at a random point in the feed (it's more accurate AT the transmitter). Does that help? Rick WA6NHC * I threw in this caveat because I once had a very nice, high power, homebrew 'tuner' that I could feed with the 200 watt transmitter and get a 'perfect match' with *nothing* delivered to the attached end fed random wire. The 'tuner' simply converted it into heat. If I retuned using a different LC combination, I was heard. Don't ask what type etc., because I don't remember and stupidly sold it over 30 years ago. :o( -Original Message- From: Tom Azlin N4ZPT Not sure I understand this. I did not think an SWR meter was supposed to work properly only when seeing 50 ohms restive. If the line is not flat it is terminated in to something other than the feedline impedance, i.e. not 50 ohms restive in this discussion. I would expect the SWR meter at some point in the feedline to be accurate under those conditions because it is supposed to measure the standing wave ratio of the feedline with respect to that 50 ohm resistive. If I then have an antenna coupler in the radio that is matching the transmitter to that non-50 ohm impedance why would the SWR meter change to inaccurately measuring the SWR? Putting the K3 into bypass or letting it tune should not change the SWR measures at some point in the feedline. The K3 may show 1:1 simply because it properly transformed the line impedance to 50 ohms restive. Perhaps I am missing something here. Sorry for continuing the discussion. 73, tom n4zpt On 1/2/2012 8:06 PM, Rick Bates wrote: Let me see if I can correctly state, with clarity for all to understand so this thread can die peacefully and we can move on (please?). The K3 puts out power into an internal tuner (if installed) and then to an SO-239 at the rear of the radio. If the tuner is in bypass, the impedance is very
[Elecraft] K3 Internal Tuner Question
I installed the KAT3 over the weekend and the construction and calibration was successful. This evening I hooked everything back up to check reception, tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a Palstar Wattmeter installed between the K3 and the antenna and for some reason I am getting a high swr on the Palstar meter of 5:1 and don't understand why. I have a multiband vertical antenna with a 4:1 Unun at the base of the antenna. Am I missing something here? A little hand holding would be appreciated. Regards, John W9QP __ 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] K3 Internal Tuner Question
The SWR displayed on the K3 is after the PA, but before the ATU. The external meter shows the SWR at the antenna, after the ATU. Dick, K6KR On Jan 1, 2012, at 20:12, John Dziedziejko dziedziej...@bellsouth.net wrote: I installed the KAT3 over the weekend and the construction and calibration was successful. This evening I hooked everything back up to check reception, tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a Palstar Wattmeter installed between the K3 and the antenna and for some reason I am getting a high swr on the Palstar meter of 5:1 and don't understand why. I have a multiband vertical antenna with a 4:1 Unun at the base of the antenna. Am I missing something here? A little hand holding would be appreciated. Regards, John W9QP __ 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
[Elecraft] K3 Internal Tuner Question
Thanks for the responses, will take the Palstar out and hook the antenna directly to the K3 and go by the K3's swr meter and power output indications. Best regards, John W9QP __ 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] K3 internal tuner question
Hello all, The internal tuner on my K3 works great. It's much better than I expected. However I've noticed something unexpected, so I'll ask the list(s). I've cleared the tuner memories (K3_EZ) and have gone to often used frequencies (local 75 meter nets for example) activated the tuner, which comes to 1:1. Then over the course of the day, I'm elsewhere in the bands. When I come back to that net channel, I check the tuning before checking into the net. The tuner clicks away and may come back with say a 3.4:1 match, so I tap it again and it settles on a 1:1 match and I operate. The antenna (a EDZ wire) hasn't moved, no significant weather (or bird) changes. Am I wrong in my understanding that the tuner remembers the frequency and associated settings for that frequency (per antenna)? My other concern is that with the limitations of the HRD software (no SWR reading), I don't know if the tuner settled on 6:1 or 1:1 (no audible clue either). Thanks in advance, Rick WA6NHC __ 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
