Construction Continued

Radio Record, Volume I, Issue 49, 29 June 1928, Page 13

Construction Continued

lars will be found in the description of the short-wave receiver construction in the "Listeners’ Guide." The coil coupling is varied by means of a kuob on the left-hand end of the spindle, which projects through 4 slot cut in the lower edge of the cover. A brake on the other end of the spindle makes the coil "stay put." FOR clearness also, the grid-bias cell is not shown, but~its position is indicated. One small round cell can be used, laid on its side. The accompanying .006 fixed condenser should be kept on the‘coil side of the screen, and may be above the bias cell. Note that where the filament terminals come up from under the baseboard, the negative is connected to an .006, and to the secondary coil via the grid battery (if used). The positive is connected to the shield. At A and B are washers screwed to the base, and under these connecting wires to the shield are held to obviate soldering to the shield, not always an easy operation with a small iron. Flament connections to the 625 are made with a small valve socket on each lead. The two .00G by-pass condensers are shown without supports, but must be so arranged as not to come in contact. with the shield. | If the 222 valve is to be used, the two filament leads will go to the valve ‘socket in the usual way. Some types of UX holder will take the plate and sereen grid end of a 625 quite well, so if a suitable holder is used it will take either type of valve. "The small internal copper screen is not shown, but its position is indicated

by a dotted line. Sufticient room is left at the sides to give free space for leads to get round. The screen is secured to the base by two serews at the side nearest to the coils. HE connection to the contrel grid for either valve is made by meaus of a small battery clip on the end of the wire, For the 625 it is a good plan to put a small piece of adhesive tape on the clip to present possible contact with a filament prong. . The lead from the screen grid (ordinary grid connection in holder) goes under the board as B45 volts, and above the board is connected through the by-pass condenser to the shield. Dimensions not already given are pesengene 12 x 6: x 3-8 and panel x 63.

In addition, there is the UX222, 42s., or the $625, 30s. A shipment of the latter has just been landed, so they will be easily procurable.

s. dd. Variable condenser ...ccceeee 15 0 Vernier Dial, high ratio ...... 9 0 2 Fixed condensers .006, mica 7 6 1 fixed condenser, .002, ...... 2 0 UX valve socket .sceseseveeees 2 8 Copper sheet, 28°S sscoseeeeeee 6 0 Rheostat, 80 obMS ....sceseeee 3 O Grid bias cell for S625......-.. 0 9 Wire, screws, terminals, bolts, OCLC, ccccccccccscccsecteere & G th to BR o oS

PARTS AND MATERIALS REQUIRED.