Hi Dan, By some chance is the feedline rolled on itself... so that either feeder is not unevenly coupled to anything around it... like gutters... or the elements of the antenna?
The long run of feed line may be better lasting in the wind if it is twisted 3-6 times a foot or so... it isn't critical.. but it does seem to balance the coupling, if there is any... to things like towers... other metal items. Just a thought, --... ...-- Dale - WC7S in Wy > Date: Tue, 22 Dec 2009 23:33:14 -0500 > From: daniel.pe...@fshsociety.org > To: elecraft@mailman.qth.net > CC: chesapeake1...@post.harvard.edu; d...@w3fpr.com > Subject: Re: [Elecraft] [KX1] Help sought KX1 high SWR on 40 and balanced > antenna > > Hi Don, > > Thanks. The antenna has the full length of ladder line 81'. It's > probably up 45'-50' at center and 35'-40 feet out from house. Mostly > vertical and drops down alongside tree and then slopes over to house. > It has not been cut. > Why is the single wire configuration so much louder than coax linear > loaded dipole on receive? > Best, > > Dan > > > Don Wilhelm wrote: > > > Dan, > > > > The Cobra Ultralight Sr. antenna needs the 81 foot ladderline intact to > > provide the proper impedance for the feedpoint in the shack. > > Apparently you cut it to something less than that. > > > > The tuner in the KXAT1 has a limited range due to its small size. I am > > certain that the tuning range of your Icom703 is greater than the KXAT1, > > so while the Icom is able to tune your modified Cobra Ultralight Sr., > > the KX1 apparently is not. > > > > I suggest you add back the length of feedline that you cut off the > > antenna - do not coil it up, but it may be supported in 'loops' to deal > > with the excess length. I believe your KX1 will tune the antenna once it > > is restored to a feedline length of 81 feet. > > > > 73, > > Don W3FPR > > > > Daniel Paul Perez wrote: > > > >> Hi all! > >> > >> I’m having a hard go of it with Elecraft products. I had a bad > >> experience with a K2 that just never worked right at my QTH. Gary at > >> Elecraft looked at it twice and said it was extremely well built and > >> an excellent sounding radio. Not for me. I finally sold it – I never > >> ever heard a clear voice on it. > >> > >> Subsequently, I purchased an Icom703Plus and it is connected to a > >> Cobra Senior Ultralight up 55-60’ at one end 45-50 at the other with > >> center up about 40-45’; 450 ohm ladder line runs about 1’ foot through > >> a casement window; to a Balun Designs 4:1 current balun; to a 3’ coax > >> with 239 – 239 connectors. The radio tunes up on all bands with > >> respectable swr and power. I turn it on and I use it – CW, LSB, USB. > >> Good reports and work DX. > >> > >> Though having had really bad luck with a QRP K2 I really enjoy reading > >> about Elecraft products and reading this reflector. There are many > >> really bright, helpful, engaged and kind folks here. So … I decided > >> to go it again with a KX1. KX1 was built by Don Wilhelm in July 2009 > >> and I have no doubt it is built extremely well. > >> > >> When I hook the KX1 to the same antenna using an amphenol 239/BNC > >> adapter e.g. Antenna setup is KX-1 | bnc/239 converter | 3 feet coax > >> 239 both ends | Balun Designs Current Balun 3Kw model 4113t | 450ohm > >> window ladder line | through casement window | Cobra Ultralite Sr. it > >> is getting respectable power and swr on 80, 30 and 20. Though 40 will > >> throw a high power value and r9.9. My first thought is there’s > >> something up with the KX1 – I’m still not sure. > >> > >> Examples: > >> > >> Before with Antenna I was getting: > >> > >> 3 525 p3.5 r1.1 > >> 7 025 p6.3 r9.9 > >> 10 112 p4.5 r2.5 > >> 14 025 p3.0 r1.6 > >> > >> With 50ohm dummy load at the end of the 3 foot coax (this is the only > >> coax in the equation both scenarios – previously goes into balun), I get: > >> > >> 3 603 p4.2 r1.0 ||||.|| > >> 7 125 p4.2 r1.0 . > >> 10 145 p5.5 r1.0 . > >> 14 025 p3.5 r1.0 ||||.|| > >> > >> I have a Diamond SX-200 meter and a Tokyo Hypower HC 200AT auto-tuner > >> in addition to the KXAT1 and the Icom’s internal tuner. So I set out > >> to try to understand this antenna’s properties e.g. un-tuned native > >> swr, forward power and reflected power. I tried turning ATU to CAL > >> and measuring SWR on the diamond meter on all 4 bands and it is pretty > >> much all over the map – it’s also hard to manually Cal the meter > >> without being able to key down. I tried this with the KX1/HyPower as > >> well and saw swr’s in the 1’s, 2 and 3’s and sometimes higher. In > >> both cases the external tuner or meter were between radio and balun. > >> I do not have something right with the KX1/Hypower my though > >> understanding is that I set menu KX1 ATU to CAL to turn off tune, > >> press buttons to ATU or key down and press tune on HyPower. I got a > >> very inconsistent set of results with the HyPower. I thought of using > >> an analyzer but am told the Cobra Senior is really difficult to > >> analyze with something like the MFJ259/269. > >> > >> I tried connecting just one side of the Cobra Sr. to the HyPower > >> wire lead and was amazed at the magnitude of difference in sound – the > >> KX1 simply came to life crackling and buzzing with all sorts of CW – > >> really astounding. Was fine with coax, but simply amazingly louder > >> with the long wire. Trying to tune the wire with KX1/HyPower gave > >> SWRs in the 4s, 5s, 6s. Tried the other wire as well with same result. > >> > >> I’m genuinely trying to figure out how to figure out what and if there > >> is a problem with the Antenna. I’m also trying to figure out what is > >> up with the KX1. Dummy load yields good power and SWR 1.0. > >> > >> Before I decide to hastily part with the KX1 and call it quits with > >> Elecraft – I thought I’d ask for some help and guidance to help me > >> understand how to make this antenna better or to understand its native > >> properties and to be able to turn on an Elecraft radio / this Elecraft > >> radio, use it, hear it and have no issues. > >> > >> Thanks for your help. > >> > >> Best, > >> > >> Dan > >> AD1P > >> chesapeake1...@post.harvard.edu > >> > > > > > > > > ______________________________________________________________ > 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 _________________________________________________________________ Hotmail: Free, trusted and rich email service. http://clk.atdmt.com/GBL/go/171222984/direct/01/ ______________________________________________________________ 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
