. QST . ne isbecoming increasingly important toamateurs. Here is a unit which performsboth functions in one package. THE advent of low-pass filters and pi-tankoutput circuits has just about made someform of transmission-line impedance match-ing a must in amateur stations. Also, if a balancedantenna and transmission line is used, mostamateuis these days prefer to put in some anced to single-ended convcision, and an adjust-able L-C section for matching to the coaxtransmission line. The complete circuit is given in Fig. 1. Barkerand Williamson type TA plug-in coils are usedfor 7i, the balanced-to
. QST . ne isbecoming increasingly important toamateurs. Here is a unit which performsboth functions in one package. THE advent of low-pass filters and pi-tankoutput circuits has just about made someform of transmission-line impedance match-ing a must in amateur stations. Also, if a balancedantenna and transmission line is used, mostamateuis these days prefer to put in some anced to single-ended convcision, and an adjust-able L-C section for matching to the coaxtransmission line. The complete circuit is given in Fig. 1. Barkerand Williamson type TA plug-in coils are usedfor 7i, the balanced-to-single-ended are designed for this purpose, being madeof tinned wire so that taps may be easily clips are furnished with each coil for makingtaps. The antenna side of the circuit is a more orless conventional plug-and-jack arrangementwhich may be connected for either series or paral-lel feed. Fig. 2A shows the plug arrangement forparallel feed, and B for series feed. The taps on. Fig. 1 — Complete schematic of the coupler. Ti should be as required for series- or parallel-tuning of the particular antenna-feeder system used (Barker & \\ illiamson type TA antenna coil used in the unit pictured). Ci, C2 — 250-nni. variable, 3000-volt rating (see text). C3 — 250-/x/if. variable, 1000-voltrating. C4 —Nine 200-/iMf. 1250-voItworking, mica con-densers. Si — 2 poles, 3 positions, steatite. S2 — 10-position progressiveshorting (Centralab PISsection, steatite). device to convert to unbalanced coaxial linebecause of its greater convenience in antenna coupler is designed to performboth of these functions in one package, and tohave enough range to accommodate any of theusual amateur antenna-feedline is achieved by using plug-in coils for bal- Xoriiian, (_)kl;i.
Size: 2191px × 1140px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectradio, bookyear1915
