K2 external auto ATU
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Advice/experience will be appreciated.
I have an upstairs shack (ugh) with much RF. Tried to earth without much luck. Should use a balanced antenna, but. I have a windom antenna cut to 20%x80%, overall length 136 feet; used for 80-thru-10 meters. It is fed with vertical twin lead for approximately 20 feet to a 4:1 balum and from there with coaxial to my rig. Whole antenna is 30 feet above the ground. Now my question. I am using a K2, and have built a KPA100 and KAT100 in separate enclosure. I would like to move the KPA100 and KAT100 in separate enclosure to the twin lead from antenna and use as an external auto ATU, then coaxial to shack, the distance being approximately 30 feet from the twin lead. I can locate external auto ATU inside of garage. What would be the problems? RF connection from K2 for 30 feet; control cable from K2 for 30 feet (maximum distance ?); 12v power? Thanks in advance - Larry (G0IKE) k2 - 2424 ______________________________________________________________ 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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Larry,
The signal in that long cable that is likely to prove troublesome is the AUXBUS. It is a one wire communications signal path for all the microprocessors in the K2 system. If the main MCU sends out a query, it expects a response in a given number of microseconds, and if that response is not received in time, the option will be declared off-line, absent, or otherwise broken. The capacitance of a long cable can also be troublesome due to shaping the edges of the relatively fast digital bits. I have no idea how long the cable could be, but Elecraft has recommended in the past no greater than 6 feet (less than 2 meters). I would suggest you cut a cable of your desired length and try it - if all functions work, then you are welcome to leave it that long, but if it does not work, you are only out the extra cable. On 2/1/2011 1:11 PM, Larry Dodson wrote: > Advice/experience will be appreciated. > > I have an upstairs shack (ugh) with much RF. Tried to earth without much > luck. Should use a balanced antenna, but. > > I have a windom antenna cut to 20%x80%, overall length 136 feet; used for > 80-thru-10 meters. It is fed with vertical twin lead for approximately 20 > feet to a 4:1 balum and from there with coaxial to my rig. Whole antenna is > 30 feet above the ground. > > Now my question. I am using a K2, and have built a KPA100 and KAT100 in > separate enclosure. I would like to move the KPA100 and KAT100 in separate > enclosure to the twin lead from antenna and use as an external auto ATU, > then coaxial to shack, the distance being approximately 30 feet from the > twin lead. I can locate external auto ATU inside of garage. > > What would be the problems? RF connection from K2 for 30 feet; control cable > from K2 for 30 feet (maximum distance ?); 12v power? > > Thanks in advance - > Larry (G0IKE) k2 - 2424 > ______________________________________________________________ > 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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In reply to this post by Larry Dodson-2
Larry, I have had the same setup at two different QTHs. With some wrangling,
you can get the RF under control. The place to put the balun is right at the window. Run coax from the balun to the transceiver, and put a line isolator (available from http://www.radioworks.com/) or some other version of choke, close to the 4:1 balun. Make a counterpoise system. Ideally, you might have one wire of 1/4 wavelength for each band that you operate, but if you can't do that, at least use several wires of different lengths. Tie them together at the shack end and connect them to the ground side of the balun. If you model the whole setup in EZNEC, you find that the least pattern distortion occurs if they run under the antenna, although of course this may not be practical. It helps if you have some sort of antenna analyzer, because the SWR and reactance presented at the output of the balun will vary as you tweak your counterpoise. But the end result is worth it. With experimentation, you should be able to get the RF in the shack down to where it's unnoticeable. This setup sounds iffy, but I'm coming up on 300 countries with exactly what you describe. Good luck! Tony KT0NY On Tue, Feb 1, 2011 at 12:11 PM, Larry Dodson <[hidden email]>wrote: > Advice/experience will be appreciated. > > I have an upstairs shack (ugh) with much RF. Tried to earth without much > luck. Should use a balanced antenna, but. > > I have a windom antenna cut to 20%x80%, overall length 136 feet; used for > 80-thru-10 meters. It is fed with vertical twin lead for approximately 20 > feet to a 4:1 balum and from there with coaxial to my rig. Whole antenna is > 30 feet above the ground. > > Now my question. I am using a K2, and have built a KPA100 and KAT100 in > separate enclosure. I would like to move the KPA100 and KAT100 in separate > enclosure to the twin lead from antenna and use as an external auto ATU, > then coaxial to shack, the distance being approximately 30 feet from the > twin lead. I can locate external auto ATU inside of garage. > > What would be the problems? RF connection from K2 for 30 feet; control > cable > from K2 for 30 feet (maximum distance ?); 12v power? > > Thanks in advance - > Larry (G0IKE) k2 - 2424 > ______________________________________________________________ > 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 > -- "We don't want every single college grad with mathematical aptitude to become a derivatives trader." -- Barack Obama ______________________________________________________________ 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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