OCR Text |
Show (EdRed by G. Douglas VTardrop, Editor of Radio Merchandising.) For the radio fan without the necessary nec-essary wherewithal to purchase a loud speaker, that described In the following follow-ing article will be found to accomplish Its purpose well. Its cost should not exceed 25 cents, so the new device Is well named "a two-bit loud speaker." The horn shown here was operated with only a Murdock 2,000-ohm re- ceiver In the base and a detector and one-step. Music and ball-scores were heard clearly and easily all over a medium-sized room and for a distance of about 40 feet from the horn. The tone was excellent and showed little or no tendency to over-vibrate on the high notes. The norn Itself Is made from stiff red cardboard similar to that used as covers for notebooks, and this material may be purchased for about 10 cents at any stationery store. Lay out the design with a ruler and compass to the dimensions shown. Cut out the parts and bend them to the required shape, taking care to make no sharp bends in the cardboard. A little trim ming may be necessary to make the edges around the curves fit nicely. The secret of assembling the horn is In the use of- surgeon's adhesive tape, which seems to have a peculiar affinity for the cardboard and makes an excellent cementing tape for the corners. This tape may be purchased at the drug store; it should be one-half one-half inch wide and cost about 15 cents. In assembling the horn, cut the tape Into strips about ten inches long and fasten the inside seams first, pressing the tape firmly in place and rubbing slightly with a small block of wood. For a short time after the outside J . ... seams are covered, the horn may be held In true shape by elastic bands The base may be any small wooden box at hand or specially constructed to any desired dimensions. The cover, which Is to support tile horn and receiver re-ceiver below, should preferably be at least one-half inch thick. To receive the horn a square tapered hole should be cut through the cover. Push the horn firmly in the hole and glue It In place or attach it on the under side ol the cover by four strips of adhesivs tape reaching up inside the horn. The cover may be hinged to the box to facilitate fa-cilitate a quick change of receivers from the head-band to the box. To hold the receiver tight against the bottom of the horn, two clips oi brass or iron should be fastened to the under side of the cover and bent in such shape as to hold one of your particular par-ticular type of receivers firmly In place. A slot should be cut In the side of the box to receive the phone cord. To operate the horn, first tune youl set to maximum loudness, using the headphones. When optimum adjustment adjust-ment has been secured, slip one of the receivers out of Its socket and under the clips In the horn base. On account of the change in capacity of the phone cord it may be necessary to readjust the tuner. A 30-foot section of lamp cord Inserted in the phone circuit will X. J ). o-j l'.f HORN BASt Loud Speaker permit the horn to be placed in any desired room without moving the receiving re-ceiving set. The horn gives considerable amplification amplifi-cation and is free from the objectionable objection-able "tinny" sounds experienced with sheet Iron horns. On the whole, the excellent results to be obtained from a horn of this type are well worth the time and trouble expended In its construction. con-struction. ( Radio News.) |