. QST . e from ordinary solderinglugs soldered to the coil at the proper points. After the JO-meter settings are noted, similarsteps can be followed on 20, 15 and 10 correct settings for the taps are likely to bemore critical than for the lower-frequency addition, it may be necessary to have morethan one set of tap points for the entire 10-meterband. With the procedure outlined above, it is ofcourse assumed that one has an bridge orcan borrow one. If none is available, the couplercan be tuned using an output indicator. An can be inserted in series with on
. QST . e from ordinary solderinglugs soldered to the coil at the proper points. After the JO-meter settings are noted, similarsteps can be followed on 20, 15 and 10 correct settings for the taps are likely to bemore critical than for the lower-frequency addition, it may be necessary to have morethan one set of tap points for the entire 10-meterband. With the procedure outlined above, it is ofcourse assumed that one has an bridge orcan borrow one. If none is available, the couplercan be tuned using an output indicator. An can be inserted in series with one of thefeeder wires and the coupler tuned for maximumoutput, as indicated by the greatest reading ob-tainable on the ammeter. This is not as accurateas the bridge method of adjustment, because onecannot be sure the line between the transmitterand the coupler is perfectly matched. Dial lampsin series with the feedline or tapped across a sec-tion of line will also serve as output indicators, as To Antenna. ^^gg AntennaCoupler (A) (B) /•7g. 3 — Dial lamps serve as an inexpensive outputindicator, and either of the two systems shown abovecan be used. In A, a single dial lamp with one-foot leadsis clipped onto the feedline. As the transmitter and cou-pler are tuned to maximum output, the dial lamp willlight up. It may be necessary to move the clip leads upthe line to find a point where sufficient coupling isobtained. At B, the dial lamps in parallel are connectedin one of the feeders. To start out, all three bulbs shouldbe connected to prevent possible burn-out. They canbe disconnected one at a time until the best indication isobtained. shown in Fig. 3. An absorption-type wavemeterloosehj coupled to the feedline can be used. Center-Fed Antennas A center-fed antenna doesnt have to be aspecific length to work well. If you can make theantenna a half wavelength long at the lowestband, fine and dandy. But if your (JTH is suchthat putting u[) a half-wave antenna would meantying the fa
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectradio, bookyear1915
