KAT500 Tuning issue
Locked
 
|
I believe I have run into a problem with the KAT500 tuner and wanted to
mention it to see if anyone else is experiencing the same issue. I just received the KAT500 tuner and the KPA500 amp and got it up and running with my K3. The KPA500 works great but I am finding that the KAT500 is unable to tune my 40 meter wire dipole on 20 meters. The best it can do is 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner in the K3 has been able to tune this antenna on all bands without issue. Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal tuner in the K3 has no problems tuning that frequency. I have two antennas, my other one is a 80 meter vertical so I switch to that for 20 meters but I don't understand why the KAT500 is unable to tune certain frequencies when the internal tuner on the K3 is able to do so. I called Elecraft and spoke to David who had me take the KPA500 out of the picture by connecting the KAT500 directly to the K3. I had the same results. David then sent me the latest unofficial KAT500 firmware 1.18 which I installed. It did not make any difference. David had me try tuning using the utility, again no difference and still unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. In general I am finding that the internal tuner does a much better job tuning my antennas then the KAT500. I wonder if anyone else is experiencing the same problem. As far as the settings on the K3 I am using the following: COnfig:PWR Set = Per Band COnfig:Tune PWR = 15 I guess I will hope that this can be addressed through a later firmware release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is fantastic, just need to resolve this tuner issue. Jerry - AC4BT ______________________________________________________________ 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 |
|
|
Jerry,
If you want some numbers to chew on. @65' a 40 meter dipole has an impedance of about 73 ohms. SWR=1.5 The same antenna on 20M has an impedance of 3788 - j1648 ohms with an SWR of 89! Very high impedance. Why the K3 matched it, I can't say. Do you think the KAT500 should be able to handle this? Their specs are for way less than this. 73 de Brian/K3KO On 12/8/2012 19:57, Jerry Weisskohl wrote: > I believe I have run into a problem with the KAT500 tuner and wanted to > mention it to see if anyone else is experiencing the same issue. I just > received the KAT500 tuner and the KPA500 amp and got it up and running > with my K3. The KPA500 works great but I am finding that the KAT500 is > unable to tune my 40 meter wire dipole on 20 meters. The best it can do is > 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner > in the K3 has been able to tune this antenna on all bands without issue. > Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal > tuner in the K3 has no problems tuning that frequency. I have two antennas, > my other one is a 80 meter vertical so I switch to that for 20 meters but I > don't understand why the KAT500 is unable to tune certain frequencies when > the internal tuner on the K3 is able to do so. > > I called Elecraft and spoke to David who had me take the KPA500 out of the > picture by connecting the KAT500 directly to the K3. I had the same > results. David then sent me the latest unofficial KAT500 firmware 1.18 > which I installed. It did not make any difference. > David had me try tuning using the utility, again no difference and still > unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. > > In general I am finding that the internal tuner does a much better job > tuning my antennas then the KAT500. I wonder if anyone else is experiencing > the same problem. > > As far as the settings on the K3 I am using the following: > COnfig:PWR Set = Per Band > COnfig:Tune PWR = 15 > > I guess I will hope that this can be addressed through a later firmware > release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is > fantastic, just need to resolve this tuner issue. > > Jerry - AC4BT > ______________________________________________________________ > 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 > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2221 / Virus Database: 2634/5446 - Release Date: 12/08/12 > > ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2634/5446 - Release Date: 12/08/12 ______________________________________________________________ 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 |
|
|
You are probably matching the losses in the feed line, when you try to load a 40 meter dipole on 20. Check the coax loss versus VSWR for 20 meters at a VSWR of 89. Please do not do this at high power
George, W6GF ________________________________ From: Brian Alsop <[hidden email]> To: [hidden email] Sent: Saturday, December 8, 2012 12:12 PM Subject: Re: [Elecraft] KAT500 Tuning issue Jerry, If you want some numbers to chew on. @65' a 40 meter dipole has an impedance of about 73 ohms. SWR=1.5 The same antenna on 20M has an impedance of 3788 - j1648 ohms with an SWR of 89! Very high impedance. Why the K3 matched it, I can't say. Do you think the KAT500 should be able to handle this? Their specs are for way less than this. 73 de Brian/K3KO On 12/8/2012 19:57, Jerry Weisskohl wrote: > I believe I have run into a problem with the KAT500 tuner and wanted to > mention it to see if anyone else is experiencing the same issue. I just > received the KAT500 tuner and the KPA500 amp and got it up and running > with my K3. The KPA500 works great but I am finding that the KAT500 is > unable to tune my 40 meter wire dipole on 20 meters. The best it can do is > 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner > in the K3 has been able to tune this antenna on all bands without issue. > Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal > tuner in the K3 has no problems tuning that frequency. I have two antennas, > my other one is a 80 meter vertical so I switch to that for 20 meters but I > don't understand why the KAT500 is unable to tune certain frequencies when > the internal tuner on the K3 is able to do so. > > I called Elecraft and spoke to David who had me take the KPA500 out of the > picture by connecting the KAT500 directly to the K3. I had the same > results. David then sent me the latest unofficial KAT500 firmware 1.18 > which I installed. It did not make any difference. > David had me try tuning using the utility, again no difference and still > unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. > > In general I am finding that the internal tuner does a much better job > tuning my antennas then the KAT500. I wonder if anyone else is experiencing > the same problem. > > As far as the settings on the K3 I am using the following: > COnfig:PWR Set = Per Band > COnfig:Tune PWR = 15 > > I guess I will hope that this can be addressed through a later firmware > release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is > fantastic, just need to resolve this tuner issue. > > Jerry - AC4BT > ______________________________________________________________ > 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 > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2221 / Virus Database: 2634/5446 - Release Date: 12/08/12 > > ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2634/5446 - Release Date: 12/08/12 ______________________________________________________________ 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 ______________________________________________________________ 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 |
|
|
In reply to this post by jweisskohl
One thing I ran into with an automatic "hi powered" tuner is that the firmware does not allow all the otherwise available values of the components on certain bands. This is done in the case of the MFJ tuner I am using (now until the KAT arrives) on 40 Meters so that the voltage and current limits are not exceeded when handling full rated power. I don't know if the KAT500 has this implemented or if in the case of the higher power capability, it just doesn't have quite the range of the 100 watt tuner in the K3.
As was mentioned in a similar thread, you might experiment by changing your feedline a few feet plus or minus to find a more satisfactory matching situation on some bands. Chuck, KE9UW Lionel Trains, TCA, LCCA, LRRC aka Jack, BMW Motorcycles BMWMOA #224 ________________________________________ From: [hidden email] [[hidden email]] on behalf of Jerry Weisskohl [[hidden email]] Sent: Saturday, December 08, 2012 1:57 PM To: [hidden email] Subject: [Elecraft] KAT500 Tuning issue I believe I have run into a problem with the KAT500 tuner and wanted to mention it to see if anyone else is experiencing the same issue. I just received the KAT500 tuner and the KPA500 amp and got it up and running with my K3. The KPA500 works great but I am finding that the KAT500 is unable to tune my 40 meter wire dipole on 20 meters. The best it can do is 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner in the K3 has been able to tune this antenna on all bands without issue. Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal tuner in the K3 has no problems tuning that frequency. I have two antennas, my other one is a 80 meter vertical so I switch to that for 20 meters but I don't understand why the KAT500 is unable to tune certain frequencies when the internal tuner on the K3 is able to do so. I called Elecraft and spoke to David who had me take the KPA500 out of the picture by connecting the KAT500 directly to the K3. I had the same results. David then sent me the latest unofficial KAT500 firmware 1.18 which I installed. It did not make any difference. David had me try tuning using the utility, again no difference and still unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. In general I am finding that the internal tuner does a much better job tuning my antennas then the KAT500. I wonder if anyone else is experiencing the same problem. As far as the settings on the K3 I am using the following: COnfig:PWR Set = Per Band COnfig:Tune PWR = 15 I guess I will hope that this can be addressed through a later firmware release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is fantastic, just need to resolve this tuner issue. Jerry - AC4BT ______________________________________________________________ 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 ______________________________________________________________ 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
Chuck, KE9UW
|
|
|
Now that I think about it, if you have a different feedline length depending on tuning from the output of the KAT or tuning from the output of the K3 with both in line, that may make enough difference in the required values to tune.
Chuck, KE9UW Lionel Trains, TCA, LCCA, LRRC aka Jack, BMW Motorcycles BMWMOA #224 ________________________________________ From: [hidden email] [[hidden email]] on behalf of hawley, charles j jr [[hidden email]] Sent: Saturday, December 08, 2012 2:33 PM To: Jerry Weisskohl; [hidden email] Subject: Re: [Elecraft] KAT500 Tuning issue One thing I ran into with an automatic "hi powered" tuner is that the firmware does not allow all the otherwise available values of the components on certain bands. This is done in the case of the MFJ tuner I am using (now until the KAT arrives) on 40 Meters so that the voltage and current limits are not exceeded when handling full rated power. I don't know if the KAT500 has this implemented or if in the case of the higher power capability, it just doesn't have quite the range of the 100 watt tuner in the K3. As was mentioned in a similar thread, you might experiment by changing your feedline a few feet plus or minus to find a more satisfactory matching situation on some bands. Chuck, KE9UW Lionel Trains, TCA, LCCA, LRRC aka Jack, BMW Motorcycles BMWMOA #224 ________________________________________ From: [hidden email] [[hidden email]] on behalf of Jerry Weisskohl [[hidden email]] Sent: Saturday, December 08, 2012 1:57 PM To: [hidden email] Subject: [Elecraft] KAT500 Tuning issue I believe I have run into a problem with the KAT500 tuner and wanted to mention it to see if anyone else is experiencing the same issue. I just received the KAT500 tuner and the KPA500 amp and got it up and running with my K3. The KPA500 works great but I am finding that the KAT500 is unable to tune my 40 meter wire dipole on 20 meters. The best it can do is 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner in the K3 has been able to tune this antenna on all bands without issue. Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal tuner in the K3 has no problems tuning that frequency. I have two antennas, my other one is a 80 meter vertical so I switch to that for 20 meters but I don't understand why the KAT500 is unable to tune certain frequencies when the internal tuner on the K3 is able to do so. I called Elecraft and spoke to David who had me take the KPA500 out of the picture by connecting the KAT500 directly to the K3. I had the same results. David then sent me the latest unofficial KAT500 firmware 1.18 which I installed. It did not make any difference. David had me try tuning using the utility, again no difference and still unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. In general I am finding that the internal tuner does a much better job tuning my antennas then the KAT500. I wonder if anyone else is experiencing the same problem. As far as the settings on the K3 I am using the following: COnfig:PWR Set = Per Band COnfig:Tune PWR = 15 I guess I will hope that this can be addressed through a later firmware release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is fantastic, just need to resolve this tuner issue. Jerry - AC4BT ______________________________________________________________ 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 ______________________________________________________________ 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 ______________________________________________________________ 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
Chuck, KE9UW
|
|
|
If the feed line happens to be near an even multiple of a half wavelength the impedance will be very high and there will be a voltage loop (HV point) at the tuner. As someone else noted, losses would also be very high, so using a 40m coax fed dipole on 20 is a poor idea.
Vic k2vco On Dec 8, 2012, at 12:37 PM, "hawley, charles j jr" <[hidden email]> wrote: > Now that I think about it, if you have a different feedline length depending on tuning from the output of the KAT or tuning from the output of the K3 with both in line, that may make enough difference in the required values to tune. > > Chuck, KE9UW > Lionel Trains, TCA, LCCA, LRRC > aka Jack, BMW Motorcycles BMWMOA #224 > > ________________________________________ > From: [hidden email] [[hidden email]] on behalf of hawley, charles j jr [[hidden email]] > Sent: Saturday, December 08, 2012 2:33 PM > To: Jerry Weisskohl; [hidden email] > Subject: Re: [Elecraft] KAT500 Tuning issue > > One thing I ran into with an automatic "hi powered" tuner is that the firmware does not allow all the otherwise available values of the components on certain bands. This is done in the case of the MFJ tuner I am using (now until the KAT arrives) on 40 Meters so that the voltage and current limits are not exceeded when handling full rated power. I don't know if the KAT500 has this implemented or if in the case of the higher power capability, it just doesn't have quite the range of the 100 watt tuner in the K3. > As was mentioned in a similar thread, you might experiment by changing your feedline a few feet plus or minus to find a more satisfactory matching situation on some bands. > > Chuck, KE9UW > Lionel Trains, TCA, LCCA, LRRC > aka Jack, BMW Motorcycles BMWMOA #224 > > ________________________________________ > From: [hidden email] [[hidden email]] on behalf of Jerry Weisskohl [[hidden email]] > Sent: Saturday, December 08, 2012 1:57 PM > To: [hidden email] > Subject: [Elecraft] KAT500 Tuning issue > > I believe I have run into a problem with the KAT500 tuner and wanted to > mention it to see if anyone else is experiencing the same issue. I just > received the KAT500 tuner and the KPA500 amp and got it up and running > with my K3. The KPA500 works great but I am finding that the KAT500 is > unable to tune my 40 meter wire dipole on 20 meters. The best it can do is > 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal tuner > in the K3 has been able to tune this antenna on all bands without issue. > Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal > tuner in the K3 has no problems tuning that frequency. I have two antennas, > my other one is a 80 meter vertical so I switch to that for 20 meters but I > don't understand why the KAT500 is unable to tune certain frequencies when > the internal tuner on the K3 is able to do so. > > I called Elecraft and spoke to David who had me take the KPA500 out of the > picture by connecting the KAT500 directly to the K3. I had the same > results. David then sent me the latest unofficial KAT500 firmware 1.18 > which I installed. It did not make any difference. > David had me try tuning using the utility, again no difference and still > unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. > > In general I am finding that the internal tuner does a much better job > tuning my antennas then the KAT500. I wonder if anyone else is experiencing > the same problem. > > As far as the settings on the K3 I am using the following: > COnfig:PWR Set = Per Band > COnfig:Tune PWR = 15 > > I guess I will hope that this can be addressed through a later firmware > release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 is > fantastic, just need to resolve this tuner issue. > > Jerry - AC4BT > ______________________________________________________________ > 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 > ______________________________________________________________ > 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 > ______________________________________________________________ > 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 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 |
|
|
Assuming that the feedline is ladder line or open wire for low loss, add
an eighth wavelength of feedline on 20 meters (about 8 feet). That may or may not help on 10 meters (the problem is thee same, the radiator has a very high impedance, and the feedline must be used as an impedance transformer to bring it down. Maybe some work with the ARRL program TLW is in order. 73, Don W3FPR On 12/8/2012 4:14 PM, Vic Rosenthal wrote: > If the feed line happens to be near an even multiple of a half wavelength the impedance will be very high and there will be a voltage loop (HV point) at the tuner. As someone else noted, losses would also be very high, so using a 40m coax fed dipole on 20 is a poor idea. > > Vic k2vco > > ______________________________________________________________ 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 |
|
|
In reply to this post by Vic Rosenthal
Right now, I have the coax from the antenna directly connected to the
KAT500. I could try using my Delta-4 switch, have the coax go to that and then a small run to the KAT500 to see if that makes a difference. The high swr is an issue on 40 and 10 meters, however, ten is manageable, it's about 1.9 - 1 and I am working around the issue but using my 80 meter vertical on 20 meters. So this is not a "show-stopper" but just wanted to understand why it was happening. Jerry - AC4BT On Sat, Dec 8, 2012 at 4:14 PM, Vic Rosenthal <[hidden email]> wrote: > If the feed line happens to be near an even multiple of a half wavelength > the impedance will be very high and there will be a voltage loop (HV point) > at the tuner. As someone else noted, losses would also be very high, so > using a 40m coax fed dipole on 20 is a poor idea. > > Vic k2vco > > On Dec 8, 2012, at 12:37 PM, "hawley, charles j jr" <[hidden email]> > wrote: > > > Now that I think about it, if you have a different feedline length > depending on tuning from the output of the KAT or tuning from the output of > the K3 with both in line, that may make enough difference in the required > values to tune. > > > > Chuck, KE9UW > > Lionel Trains, TCA, LCCA, LRRC > > aka Jack, BMW Motorcycles BMWMOA #224 > > > > ________________________________________ > > From: [hidden email] [[hidden email]] > on behalf of hawley, charles j jr [[hidden email]] > > Sent: Saturday, December 08, 2012 2:33 PM > > To: Jerry Weisskohl; [hidden email] > > Subject: Re: [Elecraft] KAT500 Tuning issue > > > > One thing I ran into with an automatic "hi powered" tuner is that the > firmware does not allow all the otherwise available values of the > components on certain bands. This is done in the case of the MFJ tuner I am > using (now until the KAT arrives) on 40 Meters so that the voltage and > current limits are not exceeded when handling full rated power. I don't > know if the KAT500 has this implemented or if in the case of the higher > power capability, it just doesn't have quite the range of the 100 watt > tuner in the K3. > > As was mentioned in a similar thread, you might experiment by changing > your feedline a few feet plus or minus to find a more satisfactory matching > situation on some bands. > > > > Chuck, KE9UW > > Lionel Trains, TCA, LCCA, LRRC > > aka Jack, BMW Motorcycles BMWMOA #224 > > > > ________________________________________ > > From: [hidden email] [[hidden email]] > on behalf of Jerry Weisskohl [[hidden email]] > > Sent: Saturday, December 08, 2012 1:57 PM > > To: [hidden email] > > Subject: [Elecraft] KAT500 Tuning issue > > > > I believe I have run into a problem with the KAT500 tuner and wanted to > > mention it to see if anyone else is experiencing the same issue. I just > > received the KAT500 tuner and the KPA500 amp and got it up and running > > with my K3. The KPA500 works great but I am finding that the KAT500 is > > unable to tune my 40 meter wire dipole on 20 meters. The best it can do > is > > 3.75 - 1 swr which trips the FAULT light on the KAT500. The internal > tuner > > in the K3 has been able to tune this antenna on all bands without issue. > > Also the KAT500 is unable to tune 28400 below 2.5 - 1 while the internal > > tuner in the K3 has no problems tuning that frequency. I have two > antennas, > > my other one is a 80 meter vertical so I switch to that for 20 meters > but I > > don't understand why the KAT500 is unable to tune certain frequencies > when > > the internal tuner on the K3 is able to do so. > > > > I called Elecraft and spoke to David who had me take the KPA500 out of > the > > picture by connecting the KAT500 directly to the K3. I had the same > > results. David then sent me the latest unofficial KAT500 firmware 1.18 > > which I installed. It did not make any difference. > > David had me try tuning using the utility, again no difference and still > > unable to tune 20 meters below 2.75 - 1 on my 40 meter wire dipole. > > > > In general I am finding that the internal tuner does a much better job > > tuning my antennas then the KAT500. I wonder if anyone else is > experiencing > > the same problem. > > > > As far as the settings on the K3 I am using the following: > > COnfig:PWR Set = Per Band > > COnfig:Tune PWR = 15 > > > > I guess I will hope that this can be addressed through a later firmware > > release. Meanwhile, the KAT500 is the weak link in my system. The KPA500 > is > > fantastic, just need to resolve this tuner issue. > > > > Jerry - AC4BT > > ______________________________________________________________ > > 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 > > ______________________________________________________________ > > 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 > > ______________________________________________________________ > > 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 > 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 |
|
|
Just to make sure we're all on the same page ...
When the tuner (at the radio) gets an acceptable match, that just means the transmitter will _think_ there is a good antenna system out there. The feedline between the antenna and the tuner will know otherwise and can have points of very high voltage that could cause insulation breakdown, and points of very high current that can cause overheating and will be a source of power loss. This isn't really a problem in QRP operations, but when you head into the QRO world it can make a difference. The antenna also has issues. In an earlier post K3KO had the calculated feedpoint impedance, and it was very far from the 'nominal' 50 ohms of your feedline or the ~75 ohms of a dipole at altitude. W6GF also gave this info in terms of SWR to show how bad it was. All in all a resonant 40M dipole makes an unhappy antenna system on 20 meters. I understand that if that is all you have you're stuck with it, but it is really time to consider something else. Maybe a fan dipole, or trap dipole? Mark AD5SS On Sat, Dec 8, 2012 at 3:30 PM, Jerry Weisskohl <[hidden email]> wrote: > Right now, I have the coax from the antenna directly connected to the > KAT500. I could try using my Delta-4 switch, have the coax go to that and > then a small run to the KAT500 to see if that makes a difference. The high > swr is an issue on 40 and 10 meters, however, ten is manageable, it's about > 1.9 - 1 and I am working around the issue but using my 80 meter vertical on > 20 meters. So this is not a "show-stopper" but just wanted to understand > why it was happening. > > Jerry - AC4BT > 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 |
|
|
Mark,
Thanks for the reply. I received quite a few replies pointing out exactly what you said. Because it wouldn't load on 20 meters I was using my other antenna, which works fine with the KAT500 (80 meter vertical). However, I was trying to understand why the 40 meter dipole wasn't working well on 20 and I thank all those that replied. This reflector is a wealth of knowledge! Now I realize my KAT500 is working as it should. Having two antennas comes in handy! Thanks, Jerry - AC4BT On Sat, Dec 8, 2012 at 5:49 PM, Mark Bayern <[hidden email]> wrote: > Just to make sure we're all on the same page ... > > When the tuner (at the radio) gets an acceptable match, that just > means the transmitter will _think_ there is a good antenna system out > there. The feedline between the antenna and the tuner will know > otherwise and can have points of very high voltage that could cause > insulation breakdown, and points of very high current that can cause > overheating and will be a source of power loss. This isn't really a > problem in QRP operations, but when you head into the QRO world it can > make a difference. The antenna also has issues. In an earlier post > K3KO had the calculated feedpoint impedance, and it was very far from > the 'nominal' 50 ohms of your feedline or the ~75 ohms of a dipole at > altitude. W6GF also gave this info in terms of SWR to show how bad it > was. All in all a resonant 40M dipole makes an unhappy antenna system > on 20 meters. > > I understand that if that is all you have you're stuck with it, but it > is really time to consider something else. Maybe a fan dipole, or trap > dipole? > > Mark AD5SS > > > > On Sat, Dec 8, 2012 at 3:30 PM, Jerry Weisskohl <[hidden email]> > wrote: > > Right now, I have the coax from the antenna directly connected to the > > KAT500. I could try using my Delta-4 switch, have the coax go to that and > > then a small run to the KAT500 to see if that makes a difference. The > high > > swr is an issue on 40 and 10 meters, however, ten is manageable, it's > about > > 1.9 - 1 and I am working around the issue but using my 80 meter vertical > on > > 20 meters. So this is not a "show-stopper" but just wanted to understand > > why it was happening. > > > > Jerry - AC4BT > > > 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 |
|
|
In reply to this post by Mark Bayern
On 12/8/2012 2:49 PM, Mark Bayern wrote:
> The feedline between the antenna and the tuner will know > otherwise and can have points of very high voltage that could cause > insulation breakdown, and points of very high current that can cause > overheating and will be a source of power loss. This isn't really a > problem in QRP operations, but when you head into the QRO world it can > make a difference. Well, yes but "loss is loss." If your transmission line exhibits 3dB loss on 20m, it will turn your 500W into 250W at the antenna, and it will turn your 5W into 2.5W at the antenna. I think you might have been referring to damage from excessive voltage/current which *is* a problem QRO and not QRP, but the loss doesn't change. 73, Fred K6DGW - Northern California Contest Club - CU in the 2013 Cal QSO Party 5-6 Oct 2013 - www.cqp.org ______________________________________________________________ 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 |
|
|
In reply to this post by jweisskohl
You don't need to add 8 foot wires for 10 meters. The 80 meter dipole will
load up there with a little help from the tuner. 73, Tony K4QE On Sat, Dec 8, 2012 at 7:27 PM, Ron D'Eau Claire <[hidden email]> wrote: > > If you want to use your 40 meter dipole on 20 meters, one way is to add two > 16 foot wires at the center feed point, putting a 20 meter dipole in > parallel with the 40 meter dipole. On 40 the extra 16 foot wires will > simply > make the radiator look a bit "fatter" to the RF. On 20, the 40 meter dipole > exhibits a very high impedance at the feed point (which is what is causing > your problem now) while the 20 meter dipole will present a decent match. > > Your 40 meter dipole already makes a decent 15 meter antenna because it's 3 > half waves long, with a relatively decent match at the feed point. > > In the extreme you could add a 120 foot wire paralleled wire so the system > will cover 80, 40, 20 and 15 meters and a pair of 8 foot wires to cover 10 > meters to make it an 80/40/20/15/10 meter system. > > That was a common multi-band antenna before the WARC bands were opened. The > mismatch is much greater on the WARC bands because they are not > harmonically-related to the others. Even though your tuner may produce a > good load to the transmitter, feed line losses can get rather high. > > Ideally you want to fan the wires to the ends are as far apart as possible, > but even several inches or a foot or so will work. > > Understand that a 2:1 or worse SWR is common even though the wires are cut > to 1/2 wavelength due to interaction between them, but the losses should > not > be serious over a typical run of good quality coax. > > 73, Ron AC7AC > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Jerry Weisskohl > Sent: Saturday, December 08, 2012 2:59 PM > To: Mark Bayern > Cc: Elecraft Reflector > Subject: Re: [Elecraft] KAT500 Tuning issue > > Mark, > Thanks for the reply. I received quite a few replies pointing out exactly > what you said. Because it wouldn't load on 20 meters I was using my other > antenna, which works fine with the KAT500 (80 meter vertical). However, I > was trying to understand why the 40 meter dipole wasn't working well on 20 > and I thank all those that replied. This reflector is a wealth of > knowledge! > Now I realize my KAT500 is working as it should. Having two antennas comes > in handy! > > Thanks, > > Jerry - AC4BT > > > On Sat, Dec 8, 2012 at 5:49 PM, Mark Bayern <[hidden email]> wrote: > > > Just to make sure we're all on the same page ... > > > > When the tuner (at the radio) gets an acceptable match, that just > > means the transmitter will _think_ there is a good antenna system out > > there. The feedline between the antenna and the tuner will know > > otherwise and can have points of very high voltage that could cause > > insulation breakdown, and points of very high current that can cause > > overheating and will be a source of power loss. This isn't really a > > problem in QRP operations, but when you head into the QRO world it can > > make a difference. The antenna also has issues. In an earlier post > > K3KO had the calculated feedpoint impedance, and it was very far from > > the 'nominal' 50 ohms of your feedline or the ~75 ohms of a dipole at > > altitude. W6GF also gave this info in terms of SWR to show how bad it > > was. All in all a resonant 40M dipole makes an unhappy antenna system > > on 20 meters. > > > > I understand that if that is all you have you're stuck with it, but it > > is really time to consider something else. Maybe a fan dipole, or trap > > dipole? > > > > Mark AD5SS > > > > > > > > On Sat, Dec 8, 2012 at 3:30 PM, Jerry Weisskohl <[hidden email]> > > wrote: > > > Right now, I have the coax from the antenna directly connected to > > > the KAT500. I could try using my Delta-4 switch, have the coax go to > > > that and then a small run to the KAT500 to see if that makes a > > > difference. The > > high > > > swr is an issue on 40 and 10 meters, however, ten is manageable, > > > it's > > about > > > 1.9 - 1 and I am working around the issue but using my 80 meter > > > vertical > > on > > > 20 meters. So this is not a "show-stopper" but just wanted to > > > understand why it was happening. > > > > > > Jerry - AC4BT > > > > > > ______________________________________________________________ > 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 > > ______________________________________________________________ > 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 > 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 |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |