WIRELESS NEWS.

Press, Volume LXIII, Issue 18900, 15 January 1927, Page 6

WIRELESS NEWS.

ELIMINATING CHAOS. ! l SE OF SHORT WAVES. ■air.*:.:.-; to.- tjie iiiess.- j ■ I'.y • l K , .cot.ra."> \ >V'.u wavc-> are the solution of the !.)ym.-iu "chaotic condition" confrontin,: l.ruadea.-iing. says Powel Crosley, jini. Jt will be a matter of only a few iiimiitlis when many American broad-fa~*-ii:lt station* will be transmitting programmes on short waves which are ;:railii;tlly coming into their own. The amateur transmitter was tlio first to lii,<l out their advantages, then commer-i-in 1 stations took them up. and now i •,!,(.• new 1-eam .-tations are usin s them. Some broadcasting .station? are at pre>riit transmitting programmes on the |,r,\vr wave bands, in addition to their j normal ones, and are lining heard eon-■-i.-tentlv at great- distance-. | Atmospheric disturbances do no: | afreet reception on the lower waio. i li-nntlis to the same extent- as found j in the present band, and it- is liiiqiios- j tionablv true that clearer reception on ♦lie lower wave lengths is possible when interference i.s encountered on the present band. The pre.-ent overcrowded broadcasting wave band is due to the fact that there nre only 8S available wave channels between 210 and o-Hj metres, and it can Ive readily seen what an enormous expansion can be made when it is realised that between 10 and 100 metres there are some L'tiOS wave lengths that can ho used, spacing, as has Ix-en the practice in the States, ll) kilocycles apart. This means that a very large increase can lie made in broadcasting stations and that each station may have an individual waveleu'itli. liroadcastintr on a short wave length, as well as the present 4'22.3 metres, will lie a regular feature of the Croslev YVf.W 30 kilowatt. (50,000 watts) super power station in Cincinnati. There will be many more stations broadcasting on short waves as the. audience increases and realises the clearness of reception on the lower band. Existing Sets to he Used. r.calising the tremendous importance of ibis new wave transmission, _ the Crosby Radio Corporation i.s making a new unit, invented by Sir Well Bruce, inn., consulting engineer of the U.S. Signal Corps, which will make it possible to receive low wave broadcasting from -10 to 200 metres with any type of valve set, thus enabling the use of the millions of sets now existing. This short wave receiver utilises three valves, but is so compact that it i.s installed in a cabinet, the panel size of which is but IOJ-in by 7in, and the eabinet depth is but Tin. Additional '•A' 1 battery power is unnecessary, but a !i[) volt "B" battery i.s required for operation of the short wave device. This unit i.s placed between the broadcasting receiver and the aerial, u itli a switch permitting the throwing out of the short wave receiver without disconnecting it. In other words, the aerial is connected to the aerial terminal of the short wave unit, and the output terminal of the new set is attached to the aerial terminal of the i broadcast set. It is reported that station 2BL, Sydney, and J OAK. Japan, are testing out- on short waves on about 39 metres. Improving Cone Speakers. Charles W. Peterson, the well-known acoustical engineer and inventor of the widely-used Crosley Slusicone, has discovered that the tone quality of the average cone speaker may be considerably improved by simply mounting it behind a hole in a board The board, or ''baffle" as Peterson calls it, serves to accentuate the low tones usually lost in radio reception For a baffle he uses a square board measuring about four feet on each edge, or a round board of equal diameter. A hole is cut in the centre of this board, the size of a speaker cone. The speaker is then mounted on the back of the baffle so t'hat the point of its cone extends through tho hole, and the. whole unit is hung near a wall.

Tho result of this arrangement is that low notes of organ music, and of orchestras or instrumental solos .are brought out with surprising clarity. The tone quality is more mellow, lull and pleasing than can be obtained with any other ordinary speaker. Music sounds more, natural, and static and other very high-pitched notes are reduced. In conducting the experiments, Sir' Peterson tried several cone _ typo speakers. While using tho Slusicone, which he developed he discovered that practically the same results could he obtained by mounting it behind a holo in tho front of a console cabinet, providing that the cabinet and_ hole were designed properly. This discovery is of tremendous importance from the manufacturing point of view, because it makes it possible to build console type sets which give unusually good quality of reproduction. The radio fan who wants to try this scheme with his cone type speaker can do so with very little trouble. Tt is usually possible to remove the base of the speaker, so that it can he mounted easily. The front of tho board may be covered With tapestry or decorated so that it presents a pleasing appearance, and then the assembly may be hung in the corner of a room or other convenient place. Although Victoria is geographically one of the smallest of the broadcasting districts of Australia, it holds pride of place amon it the States for the number of listeners, the total being more than double all the rest of the States put together. There is no doubt that this is due to the general excellence of the numbers and the quality of the artist engaged by !)LO Melbourne. It is always noticeable that if a town or province has a high-quality station, radio booms. Quality and not power is what counts. It is noticed that a crystal set of English make can now be had from as low as 9s Gd at J. I. Smail, of Carey's Buildings, Colombo street. We believe that this is exceptional value. —0 A receiver is not complete without a SKEKAVOX. Ask your dealer to demonstrate one to you. It combines sensitivity and volume with a handso'ne aiwoaranee hem? b"i'i i» •< h colour, and makes a beautiful contrast in any room.— £5 ss, "f all leading radio dealers.— Xew Zealand Representatives, Brown and Dureau, Wellington. __3