Page:Popular Science Monthly Volume 89.djvu/294

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��Popular Science MoniMy

��Telephone Headbands

THE accompanying drawings show a simple but very substantial pair of wireless headbands. All the materials needed are six pieces of spring brass (they may all be of the same thick- ness), two binding posts, four washers and two rivets.

Procure about 40 ins. of strip brass, 3/64 in. to 1/16 in. thick and about ^ in. wide. Out of this cut two pieces 12}4 ins. long. Round all ends and in one end of each drill a hole 3/16 in. in diame- ter. In the other two ends cut a slot 2]/^ ins. long and }i in. wide. This is done by drilling a series of holes with a }i-\n. bit as close to each other as possible, the entire length of the slot. The "tooth" edges remaining may be filed away or cut away with a cold chisel and then filed smooth. Do this carefully as a neat slot adds much to the appearance of the headbands. Now bend both ]Mcces in the shape shown in Fig. 2, and these pieces arc finished.

Next cut two pieces of the same material 134 ins. long and round the ends. Drill a hole 3/16 in. in diameter in both ends and bend one back at right angles, 5/16 in. from the extremity (see Fig. 2).

Now cut two more pieces ^yi ins. long. These should then be cut to ?,s in. wide. In the center of each piece drill a hole 3/16 in. in diameter. File or cut the ends to the pointed shape as indica- ted at C, Fig. 2, and bend the pieces as shown.

All cutting is now finished and the pieces are ready for assembling according to l^ig. 2.

Secure two binding posts as much like those illustrated as possible. Put one of these through the hole in tlic straight end of B so that it points in the same direction as the small leg of B. Now put on piece A by slipping the end with the drilled hole over the binding post on top of B. Next put A\ in the same manner, on lop of A, and then adtl a washer and screw the loj) of llu-

��binding post on tightly. Do the same with piece 5' and the slotted ends of

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��The brass bands, rivets and bolts needed to make the headbands

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���How the metal strips are bent and riveted together in assembling

��only slipping the binding post through the slots about yi in. from the end.

Take a small rivet and put it in the hole in the other end of B and then through the hole in C so that C is under- neath. Slip a washer o\er the free end of the ri\ ct and flatten with a hammer. Do not make it too tight as C should turn freely. Do the same with the bent end of B^ and piece C.

Adjustment is made at the binding posts for widening the bands; at the slots for short- ening them and the 'phones swivel at the ri\cts. Polish the brass or ha\e it nickel- plated. A good-looking, well- working pair of heail bands is the result of about one hour and thirty minutes' work and an expenditure of twenty- five cents.— Ch.-\s.T.W.\ndrus.

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��A Substitute for an Aerial

T often happens that the amateur wireless experimenter finds his aerial is too small to be efficient on long waves, although it may be all right for short wa\es. It is sometimes impossible to erect an aerial suitable for long waves. It has been found that b\- connecting rain i)ipes to the recei\ing set with a single wire lead-in, a fairly good aerial is IkuI for waves over a thousand meters. Arlington, about 1400 miU's rlistant, came faintly on a regular 100-foot aerial using loose-coupler and loading coil, wliile using the rain pipes that station was lieard sharp and clear with a little over half of the jirimary of the loose- coupler in circuit. The lead-in shoukl be connected to the pipe nearest the instruments. This sciienu' ma>' not work every time, but if the amateur has access to a system of ungrounded rain pipes it may pay him to try. Where the amateur can not utilize rain pipes llic oi(liii.ir\ lighlning rod, if it is in- stalk'd correctly and is ni)t broken in its entire length, will serve as an aerial in pj.ui' ol tile more convenient rain pipes.

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