Follow up on KX1 Field Ops
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Last week, I asked for the group's help when I was in the field with a KX1 and an antenna that wouldn't tune. Here's my report.
I trimmed the 66' wire that I have used as an End Fed Half Wave (with other rigs and tuners) to 41 feet, added a 15 foot counterpoise, and the rig tuned just fine. I was unable to do anything about the input voltage, since I lacked a coax jack that would have let me feed in 12 volts, instead of the internal 9v from the Lithium AA cells. So the power remained at about 1.8-1.9Watts. SWR was below 1.5, according to the KX1's display. I had left the 3S Lithium battery pack at home partly out of laziness, partly because of my fears of losing it in airport security. I did make a few contacts, so - mission accomplished. I did experience unusual QRM in a campgound in rural Montana on 40 meters. It sounded like a switching power supply - and it was across the entire band. Mostly steady, although it did stop now and then. I thought it might have been a generator from a nearby RV but couldn't hear one going. Any ideas what kind of electric interference that might be generated from nearby campers? There was a mix of RVs and tent campers at the campground. I was in a tent. Lastly, are there any mods to the KX1 that might get it to 5 watts if I put a 12v supply on it? I did the mod suggested by Elecraft, but the best I can get is around 4 watts with a 12V. I do get that on all bands. I'm in upper Michigan this week. This time with my 12V 3S Lithium battery. Keep a listen out for me! Thanks, Phil, W3HZZ ______________________________________________________________ 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 |
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Phil,
The electrical noise might have been a 12VDC to 120VAC inverter or perhaps a bug zapper. Just a guess. 73, BILL GERTH, W4RK Jefferson City, MO First Licensed 1954 CWOPS #459 4 States QRP Group KX3 (S/N 112) On Aug 22, 2013, at 12:23 PM, PHILIP GRAITCER <[hidden email]> wrote: > Last week, I asked for the group's help when I was in the field with a KX1 and an antenna that wouldn't tune. Here's my report. > > I trimmed the 66' wire that I have used as an End Fed Half Wave (with other rigs and tuners) to 41 feet, added a 15 foot counterpoise, and the rig tuned just fine. > > I was unable to do anything about the input voltage, since I lacked a coax jack that would have let me feed in 12 volts, instead of the internal 9v from the Lithium AA cells. So the power remained at about 1.8-1.9Watts. SWR was below 1.5, according to the KX1's display. I had left the 3S Lithium battery pack at home partly out of laziness, partly because of my fears of losing it in airport security. > > I did make a few contacts, so - mission accomplished. > > I did experience unusual QRM in a campgound in rural Montana on 40 meters. It sounded like a switching power supply - and it was across the entire band. Mostly steady, although it did stop now and then. I thought it might have been a generator from a nearby RV but couldn't hear one going. Any ideas what kind of electric interference that might be generated from nearby campers? There was a mix of RVs and tent campers at the campground. I was in a tent. > > Lastly, are there any mods to the KX1 that might get it to 5 watts if I put a 12v supply on it? I did the mod suggested by Elecraft, but the best I can get is around 4 watts with a 12V. I do get that on all bands. > > I'm in upper Michigan this week. This time with my 12V 3S Lithium battery. Keep a listen out for me! > > Thanks, > Phil, W3HZZ > ______________________________________________________________ > 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 |
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Bill,It is probably an AC inverter.When using my KX3 in my RV I have to turn off the inverter, QRM is very bad from it.Emory WM3M
______________________________________________________________ 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 |
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In reply to this post by PHILIP GRAITCER
Phil,
If you can get 3.5 watts or greater with a 13.8 volt supply, the KX1 is performing better than specifications. I would hesitate before trying to get 5 watts or greater out of it unless you are willing to re-design the low pass filter and install LPF capacitors with a higher voltage rating. I know hams have a habit of 'squeezing all the juice', but that may shorten the life of the PA components, especially when they are subjected to the higher RF voltage peaks present when the SWR is increased. 73, Don W3FPR On 8/22/2013 1:23 PM, PHILIP GRAITCER wrote: > Last week, I asked for the group's help when I was in the field with a KX1 and an antenna that wouldn't tune. Here's my report. > > I trimmed the 66' wire that I have used as an End Fed Half Wave (with other rigs and tuners) to 41 feet, added a 15 foot counterpoise, and the rig tuned just fine. > > I was unable to do anything about the input voltage, since I lacked a coax jack that would have let me feed in 12 volts, instead of the internal 9v from the Lithium AA cells. So the power remained at about 1.8-1.9Watts. SWR was below 1.5, according to the KX1's display. I had left the 3S Lithium battery pack at home partly out of laziness, partly because of my fears of losing it in airport security. > > I did make a few contacts, so - mission accomplished. > ______________________________________________________________ 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 |
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In reply to this post by PHILIP GRAITCER
Phil -
It is probably unusual to get a full 5 watts out of a KX1 even with a 12V or slightly better power supply. You might get pretty close if everything is perfect, but I'm happy to see 3 watts on mine. Of course, its alway amazing what you can accomplish with only 1 or 2 watts! Chip AE5KA On Thu, Aug 22, 2013 at 12:23 PM, PHILIP GRAITCER <[hidden email]> wrote: > Last week, I asked for the group's help when I was in the field with a KX1 > and an antenna that wouldn't tune. Here's my report. > > I trimmed the 66' wire that I have used as an End Fed Half Wave (with > other rigs and tuners) to 41 feet, added a 15 foot counterpoise, and the > rig tuned just fine. > > I was unable to do anything about the input voltage, since I lacked a coax > jack that would have let me feed in 12 volts, instead of the internal 9v > from the Lithium AA cells. So the power remained at about 1.8-1.9Watts. SWR > was below 1.5, according to the KX1's display. I had left the 3S Lithium > battery pack at home partly out of laziness, partly because of my fears of > losing it in airport security. > > I did make a few contacts, so - mission accomplished. > > I did experience unusual QRM in a campgound in rural Montana on 40 meters. > It sounded like a switching power supply - and it was across the entire > band. Mostly steady, although it did stop now and then. I thought it might > have been a generator from a nearby RV but couldn't hear one going. Any > ideas what kind of electric interference that might be generated from > nearby campers? There was a mix of RVs and tent campers at the campground. > I was in a tent. > > Lastly, are there any mods to the KX1 that might get it to 5 watts if I > put a 12v supply on it? I did the mod suggested by Elecraft, but the best I > can get is around 4 watts with a 12V. I do get that on all bands. > > I'm in upper Michigan this week. This time with my 12V 3S Lithium battery. > Keep a listen out for me! > > Thanks, > Phil, W3HZZ > ______________________________________________________________ > 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 |
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