A UK G call did a graphed efficiency comparison test with the 1:1 coming out on top. I will post it when re-found.
Also from http://www.theladderline.com/doublets-ladder-line-and-automatic-remote-tuner s ; (spell-checked) "There is also some debate about whether the balun should be a 1:1 or 4:1. I think 4:1 has been quite popular in the past. This perhaps comes from the thought that the ladder line is higher impedance than coax so we need to step down to get it closer to the coax impedance. On the forums, people who have modelled the antenna with software like EZNEC seem to make a fairly compelling argument that a 1:1 balun is more likely to present an impedance within the range of the tuner over a wide range of frequencies. The impedance will depend on the length of the ladder line so it's a bit of a gamble but I'm getting good results from a 1:1 current balun. After doing some reading and playing with a home brew balun, I finally took the lazy way out and splashed out on a serious balun. It's a DX Engineering BAL050-H10-AT. It's not cheap but I think it was a good investment. I don't have any hard evidence to show how good it is compared to a cheaper balun but I have a feeling that it contributes to the good performance I get with this antenna. I've had absolutely no "RF in the shack" or similar problems even at the old QTH when I had the ladder line coming into the shack. An interesting fact that I learned from the forums is the reason ladder line works more successfully than coax in a multiband situation like this. The common belief is that ladder line "doesn't care" about high SWR. It's true that ladder line usually has lower loss than coax at a given SWR but that's not the whole story. Another rather simple factor is that the characteristic impedance of ladder line is higher than coax so therefore, for a typical wire antenna over a wide range of frequency, the average SWR on ladder line tends to be lower than it would be with coax and that helps keep the loss low." -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Gilbert Sent: Sunday, 30 September 2012 8:37 AM To: [email protected] Subject: Re: [Elecraft] Balanced solution for KAT500 tuner? I don't believe that is necessarily true. Can you cite a reference to back up that statement? Or at least describe in physical terms (Q, currents, voltages, component loss, etc) why that would be so? I'm honestly curious what the difference would be. 73, Dave AB7E On 9/29/2012 2:13 PM, Adrian wrote: > 1:1 current balun has proven more efficient in conjunction with the > appropriate balanced (matchbox style)tuner. > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Robert G. > Strickland > Sent: Sunday, 30 September 2012 4:26 AM > To: [email protected] > Subject: Re: [Elecraft] Balanced solution for KAT500 tuner? > > Jim... > > Is there anything to be gained in putting a 1:1 "balanced isolator" at > the feed point of an antenna that is fed by a "parallel wire" feed > line? Does such an arrangement achieve feed line isolation while > preserving the ability of such an antenna to be driven on various > bands other than its resonant frequency? Thanks for your input. > > ...robert > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
