Exhibits at the Exhibition

Radio Record, Volume III, Issue 3, 2 August 1929, Page 30

Exhibits at the Exhibition

Tendency towards All-Electric

TROM the technical point of ji view the exhibits at the Radio Bxhibition had a singular significance. In ail there were 14 exhibits, and the fact that no less than 18 of these were demonstrating or displaying all-electric models indicates clearly the design of the set of the future. The majority of these are combined with electric gramophones. Diversity is obtained through the design of the cabinets: rather than through cireuit and valve combinations. The newer models are using the five-pronged heater type valve in all stages except the last. In the more expensive receiver super power valves are arranged in push-pull, and it is clear that the set without such a valve in the last stage has disappeared. The trend towards all-electric receivers wads. further strengthened by the fact that a large number of "A," "B," and "CO" battery eliminator combines were in evidence. Simplicity, too, is a keynote in the modern receiver... Single dial operation has‘ almost entirely replaced the multiple dials, though these are still used where sensitivity is preferred to simplicity. The details of the exhibits are as follow :- . STAND No. 1. Whitcombe and Tombs Ltd. and CoryWright and Salmon. Most prominent among the exhibits on this stand showed was the Loewe receiving set with a frame antenna and coniplete with a moving-coil speaker. ; The ‘new Loewe set using reaction resembles very closely the ordinary Loewe, but it has an extra control. Another product of interest was the Erla all-electric receiver, a beautifull; finished console model with drum dial eallibrated in kilocyeles and in de grees. A built-in dynamic speake. completes the set. _ . An exhibit of special interest was a‘ gramophone which had been con verted into a combined gramophonc and electric radio, with a dynami: speaker replacing the soundbox. Cory, Wright and Salmon’s exhibi. comprised batteries of all descriptions A super-size giving a voltage of 10 built up of 70 Leclanche cells enclosec in a neat case was something unusual By the addition of a little sal ammoniac these can be kept in working operation for some considerable time. Judging from their exhibition of batteries, the tendency.is to move away from-smal]: batteries to those built up of large: cels which will stand the greatev drain. STAND No. 2. Pp, ° ’- §Speddings, Limited. THE centre of attraction on this stand: was a Majestic set,. flanking which were arranged the. familiar Spedding products. The latest types of Mullard valves featured largely. Rest ing on each was a stripped valve show: ing the electrodes. : The Hmpire Four- a set employing the shielfled-grid valve appeared to be

built for service. It is controlled by two very finely geared dials, enabling accurate tuning. By a wave change switch both high and low frequencies can be tuned in. . Several gramophone units were in evidence, and one of these was used in conjunction with a Webster pick-up, and amplifier to supply a Magnavox dynamie cone speaker. Many of the latest Rola Cone speakers were displayed. STAND No. 3. E. Sime and Co. ~ ARGH and interested crowds drew round this stand to see the new Spartan electric radio receivers and gramophones. This is a large, handsome piece of furniture which stood in the centre of the artistically draped stand. The Sparkes Hnsemble comprises two parts. To the right was the electric gramophone, and on the top portion of this was an_ electrically driven turntable. Immediately over this is a suspensor which will hold a dozen records. When each record is finished the reproducer is automatically switched clear, lifted from the disc and slid into a magazine. The spindle now moves up and brings down the next record. The pick-up then moves on to this and commences playing. In this manner the dozen records are played, and the set automatically eut off. In the lower portion are arranged the record albums. . STAND No. 4. ¥F. J. W. Fear and Co. JDR4PED with blue and gold, stand No. 4 was an attractive sight. A

large "King" at the back, was the main feature, with all-electric King’s and Utah speaker in support. This new line of Utah speakers are of quite unusual and attractive'design. An Airzone Portable set was demonstrated at all times. when 2YA was on the air. In addition to the two new type King sets, a battery model in an oak cabinet was on show. STAND NO. 5. Harringtons, Limited. A VARIETY of product were exhibited by Harringtons, . Limited. Pilot parts included power packs constructed of Pilot parts featured largely, and these were keenly examined by interested. constructors. Outstanding among these was the new Pilot. drum dial control. This very neat attachment can be used by any constructor to replace the- separate dials. A piece of furniture, an Imperia cine(phone for theatres, etc, was more or less unusual in design. Two electric turritables were provided with gramophone pick-ups so that continuity was ensured, and above this a rack served as a record magazine, Other exhibits were a public address unit complete with microphone and amplifier, a silver Marshall power amplifier of five valves, including two 250’s in push-pull, Atwater Kent, Magnavox and Rola speakers. STAND NO. 6 AND 7. Radiola-Amalgamated Wireless. (THERE was no partition between these, and a very attractive display was the result. Several of the

new all-electric Radiolas were featured and demonstrated during the exhibition. One, an all-electric combination: gramophone pick-up and radio set, proved itself capable of attracting a great deal of attention. A novel exhibit was a huge dynamic cone speaker ‘with a baffel in light grey oak built in the form of a’sereen. A centre piece of colour caught the eye. Around the walls were hung several Marconi speakers, and being of the latest design, these proved quite effective wall decorations. A table. of Radiotron valves showed visitors the latest that the R.C.A. are turning out as far as vaives are concerned. STAND NO. 8. . Cossor Melody Maker. "THIS was the only stand in the exhibition featuring small ‘batteryoperated sets. The stand was brightly decorated in orange and yellow. To the sides were two assembled Cossor sets and on a central table was a:Cossor with the lid removed. At the back of this was a loop antenna which could be plugged in to replace the antenna coil so that the local station could be received without aerial or earth. ‘Instructions showing the assembly of the sets were arranged. on the wall, and visitors could then see the set in kit form, how it was assembled, and the assembled set. , STAND No. 9. Atwater Kent. VARIETY of sets, ranging from handsome consoles to’smal shielded table models were on view at this stand. A new shield grid Atwater Kent was featured. This is a very

jieat receiver, finished in a metal Shielfied case. On removing the lid a workmanlike job could be seen; everything is perfectly shielded, including the three screen-grid: radio frequency valves, the coils, condensers and power pack. To show that the-set is well constructed and well wired, one had been reversed to reveal the wiring. Everything here was neat and in or-

der. Several speakers were also exhibited. Novel lighting effects were obtained by.a candle type electric fittings, making in all a neat and attractive stand. STAND NO. 10. ; Macquarries, Ltd. Steinite Radio. T this stand the new line of Steinnite radio was on view for the first time. ‘The design is most unusual, and very pleasing. Of the large combination medel the upper portion is devoted to a wireless set with a gramophone ‘turntable in the lid. The lower part contains the speaker and record albums. This receiver was demonstrating ‘during the exhibition. The smaller model Steinite radio set only was also on view. Several Cossors in kit form and-one in assembled set completed the exhibit. ~ STAND NO. 11. -Macquarries, Ltd. THE outstanding exhibit here was a * eonsole Crosley Show Box, with turntable and pick-up built in. The speaker. was a Crosley Dynacone, finished in silver crystalline. Other Crosley models were displayed-the Show box and Gem box. Artistic light shades .gave to the exhibit an added warmth. STAND NO. 12. ‘ Kirkealdie and Stains. HIS contained four Majestic A.C. receivers, each of a different type. One of these had been adapted from the model 71 by Kirkcaldie and Stains. An addition has been made to the top portion, enabling the inclusion of a gramophone turntable with a pick-up. it is difficult to believe that these are ‘ not being turned out directly from the factory. "Model 181, the big combination set, was used to demonstrate reception from 2YA.° STAND No. 13. _ Philips Lamps, N.Z., Ltd. A NOTH of originality was struck in "the furnishing: of this stand, The

name Philips was formed by valves and the flood lights above them gave a very artistic effect. The stand was furnished like a sitting-room, with a fireplace, chairs, etc.. A full range of speakers, including the new. dynamic, was on view. Philips new Q-P (Kewpie) local station receiving set. deserves special mention. This is a very small receiver

no larger than a Philip’s battery eliminator. In appearance it is altogether different from a receiver. One simply presses the button and listens to the local station. Neither aerial or earth is necessary for the local station, with the result that the set can be moved about from room to room. The A.C. 883 is a self-contained 3valve A.C. set. The amateur obtains the parts and the circuit and builds this up for himself. A large assortment of trickle chargers and power packs were displayed. STAND No. 14. L. M. Silver and National Electric. S far as L.M. Silver was concerned, Kuprox rectifiers and eliminators were the main features. Crosley sets and speakers were also in evidence. An unusual effect was produced by lengths of Laker steel masts around the stand. National Hlectric BHngineering Co. exhibied their néw H.C. table model Fadas. A gramophone pick-up complete with motor and tone-arm was on view, and ran continuously, showing that it was capable of very smooth motion. . STAND No. 15. ; Ballinger’s. SRAM valves and Peerless speakers were featured on this stand, with a very fine piece of furniture in the centre, made by ‘Ballinger and Company themselves. This was a model wireless set, with an amplifier using a 250 in the final stage. This was operating during most of the exhibition, and during the: football broadcast large crowds gathered to listen-in. ‘STAND No. 16, ‘Post and Telegraph Department. ARGE and interested crowds gathed round this stand to see the many types of scientific apparatus displayed. The"attendants did a great deal in the way of testing apparatus that amateur

constructors' brought along. The gear for testing carrier current (wired wireless) drew much attention, and a great deal of interest in this new possibility was evoked. An apparatus to measure capacity by the hetrodyne principle received much attention, while a fading indicator kept continuously on a broadcasting station, showed very clearly how the output from this was being received. A simple meth 1 of measuring ‘stance was that of the neon lamp apparatus, "he number of flashes per minute, indicating the resistance. STAND No. 1%. "The Radio Record." ISITORS to the exhibition were generally interested in the collectlon of obsolete radio apparatus displayed on the "Radio Record" stand. This was centred about a very complete ease of valves representing types dating from the de Forrest valves in 1912 to the modern valve, and a set of tuning coils, constructed in 1918 for use on the wave band between 4000 and 23,000 metres. The tickler and aerial coils each exceeded 2ft. 6in. in length, and were about 5ft. in diameter. The tuner, primary, and, secondary, comprised two coils about 18in. long and 8in. in diameter. One moved one within the other. Interesting radio curios from the late war showed the pror.ess radio has made during the last ten years. In contrast to these was a modern power amplifier designed and constructed by "Pentode." This was operated from a gramophone ‘pickup and in conjunction with the original erystal set described by "Megohm" 2YA was brought in at excellent strength and quality. "Pentode" and the Technical Editor were in attendance to answer the constant stream of inquiries regarding the exhibits and radio problems confronting constructors. Sample copies of the "Radio Record" were distributed -by members of the staff. STAND No. 18. Amateur Radio Society. THE exhibits of the winners of the competition organised by | the

Amateur Radio Society were closely examined by. a very large number of exhibition visitors, The winner in each sectio.. called forth much praise for their neatness in construction, and general finished appearance. Other exhibits were an -"Heonomy One"’-a one-valve home-constructed receiver with a glass panel, a erystal set which had won a prize in a. London exhibiand an assembled kit-set. This latter was the work of an experienced set builder and showed constructors how wae" about these apparently simple ohs. STAND NO. 19. . The Amateur Transmitters. IN the centre of this exhibition was a large power amplifier which had ‘been constructed to supply the power to a very neat transmitter assembled as a separate unit. This transmitter uses one of the special Marconi valves which, with suitable coils, will tune down to 5 metres (600,000 kilocycles). Probably the most novel exhibit on the stand was the transmitter and receiver of 2GA. These were both fitted into a eabinet about 20 inches high, 8 inches deep, and 20 inches wide. In the top compartment are two metal cans containing the receiver and the transmitter. The change-over switch in the lid enables either to be used. With this apparatus two-way communication with Spain has been accomplished. There were very many neatly-built transmitters, ranging in size from one slightly larger than a one-valve receiver to complete outfits standing 4ft. high. The receivers exhibited were very well made, aid amateur short wave enthusiasts examined them with interest to get ideas for the constrluction of their own sets. The stand was brightly lit with small lamps which made the display quite cheerful. QSL ecards from all over the world covered the walls, and some interesting "Ham" photographs: were on view.