KXPA100 + KX3 ATU High SWR
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All, hopefully someone can tell me what I'm seeing is expected behavior, as
I've only had my KXPA100 attached to a end fed antenna at my house since I got it and it's work great. Yesterday I took the KXPA100 and KX3 out for field day. We used two antennas, a Alpha Antenna vertical and a GR8V dipole, each attached to the KXPA100. On the KX3, PA MODE is set to ON and TUN PWR is set to nor. I have both an ATU in my KX3 and KXPA100. The KXPA100 has always been in AUTO mode at home with no issues. When we tuned the AA vertical from the KX3, we had no issues, full power @ 100W, low SWR readings. Everything was great. Again we are in AUTO mode since that's what it was last set to in my house. Out in the field, when hooking the dipole up, I used the same procedure as in my house, selecting a band/frequency, tapping the ATU TUNE button on the KX3 to allow the ATU in the KXPA100 to tune the antenna to an 1:1 or 1:1.2 setting and then transmit. Right after transmitting, 4 out of 5 times we would get a flashing SWR fault light on the KXPA100 that would last for 8 seconds. We switched coax and switched from ANT1 to ANT2 and received the same results with the dipole. Is this expected behavior? I would think the KXPA100 would see that it has a tune setting in memory and setting it to Auto mode, it wouldn't throw up that SWR error? ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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When you refer to the KX3 Tuner are you talking about the one in the amp
or the rig? If the tuner is in the rig all your tuning, inless in standby on the amp, is the input circuitry of the amp and you will get a good SWR everytime. If the amp is in the PA then check the connectors on the antennas. The Elecraft tuners will tune a lot of marginal antennas but I doubt they will do an open or shorted connector. On 6/28/2015 11:37 AM, Kyle Krieg wrote: > All, hopefully someone can tell me what I'm seeing is expected behavior, as > I've only had my KXPA100 attached to a end fed antenna at my house since I > got it and it's work great. > > Yesterday I took the KXPA100 and KX3 out for field day. We used two > antennas, a Alpha Antenna vertical and a GR8V dipole, each attached to the > KXPA100. On the KX3, PA MODE is set to ON and TUN PWR is set to nor. I > have both an ATU in my KX3 and KXPA100. The KXPA100 has always been in > AUTO mode at home with no issues. > > When we tuned the AA vertical from the KX3, we had no issues, full power @ > 100W, low SWR readings. Everything was great. Again we are in AUTO mode > since that's what it was last set to in my house. > > Out in the field, when hooking the dipole up, I used the same procedure as > in my house, selecting a band/frequency, tapping the ATU TUNE button on the > KX3 to allow the ATU in the KXPA100 to tune the antenna to an 1:1 or 1:1.2 > setting and then transmit. Right after transmitting, 4 out of 5 times we > would get a flashing SWR fault light on the KXPA100 that would last for 8 > seconds. We switched coax and switched from ANT1 to ANT2 and received the > same results with the dipole. > > Is this expected behavior? I would think the KXPA100 would see that it has > a tune setting in memory and setting it to Auto mode, it wouldn't throw up > that SWR error? > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > -- R. Kevin Stover AC0H ARRL FISTS #11993 SKCC #215 NAQCC #3441 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Kyle Krieg
Kyle,
I suspect you do not have a real problem. It is much better to set the KXAT100 to MAN after having 'trained' the tuner in AUTO by tuning into each band segment (and band) that will be used with a particular antenna. In MAN the KXAT100 does not automatically attempt to retune based of frequency and SWR. It will remember the proper settings and switch to those if you change bands or band segments. IMHO, it would have been better to label the AUTO position "TRAIN" instead, but we have what was decided when the labels were 'thought up'. The condition is that there is a very short but finite time difference between when the forward power and the reflected power is measured. If the forward power is measured when the power is low and the reflected power is then measured when the power is higher, the computed SWR will be higher than actual. When the computed SWR is found to be high, the KXAT100 will try to retune (if in AUTO), or throw a fault condition (or both). That usually happens more in SSB mode due to the difference in power created by the syllabic nature of speech, but it can occasionally happen during CW if the timing is such that the forward power is measured during an inter-element space and the reverse power is measured during a dit or DAH. 73, Don W3FPR On 6/28/2015 12:37 PM, Kyle Krieg wrote: > All, hopefully someone can tell me what I'm seeing is expected behavior, as > I've only had my KXPA100 attached to a end fed antenna at my house since I > got it and it's work great. > > Yesterday I took the KXPA100 and KX3 out for field day. We used two > antennas, a Alpha Antenna vertical and a GR8V dipole, each attached to the > KXPA100. On the KX3, PA MODE is set to ON and TUN PWR is set to nor. I > have both an ATU in my KX3 and KXPA100. The KXPA100 has always been in > AUTO mode at home with no issues. > > When we tuned the AA vertical from the KX3, we had no issues, full power @ > 100W, low SWR readings. Everything was great. Again we are in AUTO mode > since that's what it was last set to in my house. > > Out in the field, when hooking the dipole up, I used the same procedure as > in my house, selecting a band/frequency, tapping the ATU TUNE button on the > KX3 to allow the ATU in the KXPA100 to tune the antenna to an 1:1 or 1:1.2 > setting and then transmit. Right after transmitting, 4 out of 5 times we > would get a flashing SWR fault light on the KXPA100 that would last for 8 > seconds. We switched coax and switched from ANT1 to ANT2 and received the > same results with the dipole. > > Is this expected behavior? I would think the KXPA100 would see that it has > a tune setting in memory and setting it to Auto mode, it wouldn't throw up > that SWR error? > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Make sure you are running the latest firmware. I observed similar symptoms some time back, and the root cause was resolved in a firmware update.
73, Matt VK2RQ On Sun, Jun 28, 2015 at 3:16 PM -0700, "Don Wilhelm" <[hidden email]> wrote: Kyle, I suspect you do not have a real problem. It is much better to set the KXAT100 to MAN after having 'trained' the tuner in AUTO by tuning into each band segment (and band) that will be used with a particular antenna. In MAN the KXAT100 does not automatically attempt to retune based of frequency and SWR. It will remember the proper settings and switch to those if you change bands or band segments. IMHO, it would have been better to label the AUTO position "TRAIN" instead, but we have what was decided when the labels were 'thought up'. The condition is that there is a very short but finite time difference between when the forward power and the reflected power is measured. If the forward power is measured when the power is low and the reflected power is then measured when the power is higher, the computed SWR will be higher than actual. When the computed SWR is found to be high, the KXAT100 will try to retune (if in AUTO), or throw a fault condition (or both). That usually happens more in SSB mode due to the difference in power created by the syllabic nature of speech, but it can occasionally happen during CW if the timing is such that the forward power is measured during an inter-element space and the reverse power is measured during a dit or DAH. 73, Don W3FPR On 6/28/2015 12:37 PM, Kyle Krieg wrote: > All, hopefully someone can tell me what I'm seeing is expected behavior, as > I've only had my KXPA100 attached to a end fed antenna at my house since I > got it and it's work great. > > Yesterday I took the KXPA100 and KX3 out for field day. We used two > antennas, a Alpha Antenna vertical and a GR8V dipole, each attached to the > KXPA100. On the KX3, PA MODE is set to ON and TUN PWR is set to nor. I > have both an ATU in my KX3 and KXPA100. The KXPA100 has always been in > AUTO mode at home with no issues. > > When we tuned the AA vertical from the KX3, we had no issues, full power @ > 100W, low SWR readings. Everything was great. Again we are in AUTO mode > since that's what it was last set to in my house. > > Out in the field, when hooking the dipole up, I used the same procedure as > in my house, selecting a band/frequency, tapping the ATU TUNE button on the > KX3 to allow the ATU in the KXPA100 to tune the antenna to an 1:1 or 1:1.2 > setting and then transmit. Right after transmitting, 4 out of 5 times we > would get a flashing SWR fault light on the KXPA100 that would last for 8 > seconds. We switched coax and switched from ANT1 to ANT2 and received the > same results with the dipole. > > Is this expected behavior? I would think the KXPA100 would see that it has > a tune setting in memory and setting it to Auto mode, it wouldn't throw up > that SWR error? > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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