280 



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 tlie 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 



A and .1' 



The brass bands, rivets 

 and bolts needed to 

 make the headbands 



PjlffT^ BINT mm iHAPf DifOHf Jl^^tMBum 



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. 



I 



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. 



