WIRELESS NEWS.

Press, Volume LXI, Issue 18413, 20 June 1925, Page 13

WIRELESS NEWS.

FITTING UP PANELS.

A FEW HINTS AND TIPS.

(SPECHLLT WRITTEN' TOP. "THE HUS3S.")

(By "Electra.")

The fitting up, drilling and, finishing of the panel for a radio set is generally the caus© of a lot of worry to the builder, so a few tips should not go amiss.

Now that panels are obtainable ready cut in almost any size required, those fitting up their own panels can avoid the trouble of cutting. If this work has to bo done, however, a useful saw for the job is ono of the brass-backed variety. Should tho panel be at all warped, warm it and placo betwen two flat, thick boards with a heavy weight on top. A few hours in this position, will generally remove tho fault. JJ'or marking out, a T-square used in combination with a sct-squaro will produeo tho most accurate results. Tho sides should first bo tested with a square and any inaccuracies coreeted with a secondcut file. The panel must be held in vice between two, pieces of wood for this operation. All marking off should be done on the reverse side, with a steel scriber. On no account uso a pencil, as any lead marks not removed during the final polishing may cause serious leaks detrimental to tho working of tho set. When drilling lay the panel on a flat board and slightly decrease pressure on the drill when on the point of penetrating. This precaution will decrease the risk of chipping tho face of the ebonite. The drilling should not bo done at a high speed; if it is. the drill will become heated and will probably bend, with risk of breaking and damage to the panel.

Take care that holes for wood screws aro of full clearance size, as any forcing .of such screw's may break off a whole corner when screwing down. Where large holes have to he drilled for such purposes as mounting one-holc-fixing components, put a pilot hoi© through the first, then drill to' size from the front sido in order to avoid cracking. All holes should be slightly counter sunk on both sides, the drill always having a. slight tendoucv to form a ridgo around the hole. Moreover, this little extra trouble ensures that all fittings, terminals, etc., will screw down flush. A small size carpenter's rose-bit is better for this job than a large drill. After drilling ,tho panel should bo rubbed down both Bides and polished." When all terminals; components, etc., hriyei bqen mounted, evdry part Ito which a connexion has to be made should be well tinned with solder. The writer always files flat all terminal ends, etc., before mounting. All brass tabs are treated in the same way, since these are usually lacquer-finished,' on which solder will not. take well. The ends of any flex connexions should be twisted and dipped into molten solder. This, prevents fraying as well as making a good connexion under the nut ,or screw by which they arc held. After the various lengths of. bus-bar wire have been cut and bent, turning the ends is essential. Where T or buttjoints are made in" this'wire, it is a good plan to run a film of solder on the. side. As. the tin-coating on -wire is riot very thick, this precaution will enable a much better joint to be made. Give every joint a-pull with the finders after soldering to make certain it i,s sound and not a "dry" ono. See that those leads at earth potential are nearest tho panel; allow ample spacing and arrange thoso leads at the opposite potential—H.T. and H.F.—to cross at j rieht angles so-as to avoid any interaction. ' *

MICA. Mic-a is used extensively in tho radio industry. Perhaps you "have seen itused in the "windows" of the olu woodburning stove. It is probably best known as "isinglass," although entirely different in texture. Isinglass is the form of gelatin which is obtained from large fish bladder, such as that of th« sturgeon. Mica., whi«h is used in many forms for commercial work and extensively in rp.dib apparatus as an insulating material, is a mineral silicate-'that readily separates into thin leaves and is .more or less elastic. Although mica has been found in some parts of tho U.S.A., it, is not of tho fin© quality mined and imported from India. Thero is a great deal' of this»American inio» used. '

Mica.is mined with hand picks in tho smaller mines, while pneumatic drills are used (with great care) in the larger mines. .When taken from the mines, mica ranges in size from a few inches to several feet in diameter and the better ouality has brought £250 a ton. Splitting knives are used to separate. the mica into sheets of the required thickness. A good splitting for a day is about three and a half pounds.' Only tho clear mica free from mineral and air bubbles should bo used: in-radio work.

2YK AND 2YB. Both are 6ituated in Wellineton, fhe former being of 100 watts and the latter 15 watts power: Both work on a wave length of 285 meters. 2YK works on Tuesday, Thursday and Sunday evenings, from S to 10 p.m., and. 2Y8.-every afternoon from 3.80 •to- 4.30. except Saturday and Sundav. Also 2YB puts out a children's haftl:our from 5 to 0.30 p.m. 2YK is to be rebuilt somo time this month so will very likely, be off the air for a time.

HERE AND THERE. Under the new Wireless Bill, an Englishman's home will no longer be his castle. If there is a suspicion that he is getting wireless on the cheap, a justice of the peace may order his house to he searched, and if an apparatus is found it will be seized. In addition, he is* liable to twelve months' imprisonment or a fino not exceeding £IOO. The reason for the new policy is that while 1,300,000 people pav the fee for listening-in, there are 2,000,000 pirates. A popular dodge is to rijj an invisible aerial beneath the roc? or even. in. a bedroom ; so that concerts may \<& heard while householder is in bed. When the dealer declare-? that the set he will eell vou will receive from a certain distance, ask him to guarantee it. Use a' rubber mat under your storage battery to protect carpets or rugs. , If your set does not seem to work well when listening to a certain sta-tion,-try another station. It may not be the fault .of your set.

A larce aerial picks up more energy but it may be in atmospherics form as well as radio energy. . I have heard from good authority that an agreement has been reached lwtween the Government and the Broadcasting Syndicate, and that this , month should see something definite being done towards an efficient broadcasting service. It is to he hoped that this will be more than a rumour and that at last we shall receive something worth while.