It comprises as per conjunction; the input; http://www.palstar.com/manual_bt1500a.pdf
"Input balun 1:1 current type balun Impedance Range 2500 +/- j2500 160 m to 20 m (assuming Resistive load) 1000 +/- j1000 17m to 10m A single-ended L-network - the most common variety - uses a certain value of inductance (L) and a certain value of capacitance (C) to effect a match at a particular frequency for a particular antenna feedline impedance and length. For coaxial cable systems, the single-ended L-network provides the lowest loss of any network matching system. However, one limitation is that with the capacitor on the antenna side of the coil, the system is limited to antenna terminal impedances greater than about 50 Ohms. If we wish to use the single-ended network with a balanced feedline, we have to add a balun on the output side of the network. Baluns work best with very low values of reactance on their output terminals, a condition that is difficult to obtain with most antennas that use parallel feedlines. The balanced version of the L-network overcomes this limitation by providing a true balanced output directly from the network. For a particular antenna, operating frequency, and transmission line impedance and length, the matching circuit requires the same total circuit inductance and the same output capacitance as the single-ended network. However, the balanced circuit divides the inductance into two equal series portions, one in each leg of the network. The shunt capacitor has the same value in both versions of the L-network. Unlike the single-ended L-network, the legs of the balanced L-network are both above ground potential. Hence, both the input and antenna sides of the network are balanced. In order to accommodate the single-ended transmission line from the transmitter, the tuner places a 1:1 choke (current) balun between the input side of the network and the transmitter coax connector. The balun converts the unbalanced input from the transmitter to a balanced condition for the network. As well, it suppresses currents that might otherwise appear on the braid of the transmitter cable." -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Gilbert Sent: Sunday, 30 September 2012 10:57 AM To: [email protected] Subject: Re: [Elecraft] Balanced solution for KAT500 tuner? Sorry for any confusion. I thought you were trying to say that a balanced antenna tuner with a balanced current choke was generally more efficient than an unbalanced tuner with a balanced current choke. Was that your intent? If so, why? 73, Dave AB7E On 9/29/2012 3:37 PM, David Gilbert wrote: > 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 ______________________________________________________________ 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
