My KX-1 has KXB3080, KXAT1, KXPD1 options. I use a three wire vibroplex iambic brass racer paddles instead of the KXPD1. Thanks for the answers received on the previous inquiry. I’ve not tried all the suggestions. The antenna does not fold back onto itself and has several twists and does not run parallel to any metal or surfaces.
Per one suggestion I tried a 1:1 Balun instead of a 4:1 and this was less effective. Having tried to tune the KX1/Cobra with a Tokyo HyPower HC 200-AT I had some subsequent thoughts / questions. To use the KX1 external tuner I switched MENU ATU to CAL. Then when I then press to Tune it appears that the KX1 sends out dits not a continuous tone. My thinking being let the KX1 ATU function key the transmitter in manual mode and while that was happening press tune on the THP. It seemed like it was hit or miss with the THP with dits and was a little better when I keyed dahs with pressing Tune on the external ATU with internal ATU being off. Very interesting also to see that the dits peaked SWR on the beginning side of the signal and the dahs bounced back to a SWR peak at the end of the tone lower than the overall SWR meter reading on the THP. First question how would one key down the KX1 to use with the THP? What is the best way to use the KX1 internal functions with an external tuner? And is using dits and dahs sufficient for THP? I think it needs a longer duration signal. The KXAT1 seems to do this? Second question, I previously asked, why using one side of the Cobra to the long wire lug of the THP was so much louder than the 450 ladder line } 4:1 balun | coax? Is this a clue that helps optimize this situation? I thank you for your patience and I appreciate your advice and thoughts in advance. Dan Ad1p > 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 >> >>> 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
