I can attest to what Vic says. I have an 88-foot long doublet, hung about 45 feet up, fed with 85 feet of 600-ohm ladder line. At the shack end I have a 1:1 balun, and then about six feet of RG/8X running to the K3. The K3's tuner likes the combination. I tried replacing the 1:1 balun with a 4:1 from the same manufacturer. The K3 was quite unhappy with the change in components. The 4:1 went back on the shelf, the 1:1 went back inline. YMMV
Jim / W6JHB On Thursday, Dec 8, 2011, at Thursday, 9:14 AM, Vic K2VCO wrote: > It is a common misconception that a 4:1 balun is the best choice to feed a > tuned balanced > line. The assumption is often made that this is appropriate because the > characteristic > impedance of ladder line or open-wire line is higher than the 50-ohm coax > that's connected > to the balun's input. > > Actually, since the tuned line is being operated at a high SWR, the impedance > seen by the > balun will vary all over the map. It may be very high or very low. This is a > very tough > job for the balun, and in some circumstances it can be quite lossy. This is > why a real > balanced tuner is better than an unbalanced tuner followed by a balun. > > A 1:1 balun is likely to have lower losses in this application, although > there might be > combinations of frequency and line length where a 4:1 is better. I hope that > Elecraft is > planning to make their balun either 1:1 or switchable. ______________________________________________________________ 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
