Simplicity, Power and Economy

Radio Record, Volume III, Issue 54, 25 July 1930, Page 28

Simplicity, Power and Economy

The Imoressions of a Technical , -Visitor to the Show

By

TECHNIQUE

HE Wellington Radio HPxhibition has revealed many technical features of interest, not -the least being. the stabilisation of radio... Last year, the first of the electric "i. receivers were displayed, for it was in this year that the great movement from batteries to a.c. sets took place. Now that it has been established for. eighteen months, we are in a position to judge the probable outcome of the change. In the first place there are no radical changes, not even in the universal adoption of the screen’ grid, for though this valve is used in almost every radio set, it is not universal. Some of the best Sets are not using it in any form, while others are employing it only in the detector stagethis is a development of the past yéar, There is even a return to the dire«tlyheated 226 type of valve. and one rereceiver at least uses four of these valves in the radio-frequency stages, 2 sereen-grid detector, and one 226 audio followed bv the popular 245,. For a power valve the 245 takes a grent deal of surpassing, and it is not surprising that medium-priced sets are using this valve in push-pull in the last stage. The 250 is still used in the more expensive sets. It has a fuller tone and, of course, can handle far greater volume. The 171 has (¢lisappeared from all but an occasional kit set. Standardisation. q[t is interesting to note that most of the manufacturers are sfan-

dardising on one chassis and placing this in various cabinets to suit the pocket. of the purchaser. The larger ones are combined with the ' electric gramophone. These small sets are capable of giving amazing reproduc. tion and compare very well with the more expensive models. Beside these there were others of two, three and four valves, all a.¢c., which cost only n moderate sum. These were distinctly popular, and the dealers report many inquiries. The combination of radio and gramophone is a feature of the stabilised models, Every maker is combining these two musical instruments into their larger sets. The smaller ones have facilities for connection to a gramophone, so that the purchaser will need only a pick-up to convert his gramophone into an electrical one. A single switch changes from one to the other, and in some eases cuts off the motor. An interesting combination was one that would play fifteen records without attention, for it automatically changes the records and stops the machine when the magazine is empty. Records of both sizes eould be accommodated, and there was ample room for storage, several albums. being

provided. In fact this was a feature of many of the combination sets-the albums formed part of the design. The Tone of the Season’s Sets. HE tone of the sets differed more . than one-would expect, probably to cater for the tastes of those who would make the-selection. In some

VUBISIEE BLS Rel HGOUIISIE the bass was prominent, too much su in the writer’s opinion, while in others the treble was accentuated, giving a harsh metallic effect. Some had a canned, sound when turned up or a suppressed sound when lowered. But they all found favour in the differing re quirements of the visitors. There were, however, some distinctly fine out fits. where realism was indeed present. The colour and perfection achieved by some of these models will take a considerable amount of surpassing. Radio has indeed reached a stage of wellnigh perfection. Bass Overdone. N interesting occurrence convinced the writer that in some sets at least the bass is much overdone. The studio had been broadcasting and it was announced that the station would = go over to the Town Hall. When this took place all the sets in the’ hall should have closed down. One was a little late in doing so and the writer lieard the orchestra on the stage coming through a set which he could not see. There was a plethora of bass, but the instruments on the stage were few in number and the bass limited to a ’cello. Then the set closed down, and so did the bass. It was strangely absent from the actual performance, but the violin which was playing the airy was much strorger. The set was never identified for there was a crowd in the hall at the time.

Novelties at the Show. QNE of the stands had a novel attraction. Describing their models as "the set with the punch," a punching arm moved regularly towdrd a fanshaped log of stations received by one listerer.. The stations were arranged with their appropriate dial settings. There were 109 in all. Another novel exhibit was a lampshade designed by Mrs. G. G. McQuarrie. With the basic Maori ¢éolours, used in an original setting of a Maori pah, the shade was most artistic and attracted great interest. It was true to detail and most realistic. On the

stand there were some particularly fin Maori mats. , The constructor and the battery se user were not catered to any extent Only two stands displayed components and these were in the form of kit se or the parts used for standard circuits. There were kits for the Loftin Whit with even the metai base alread drilled. Several assembled _ kitset: were displayed on one stand and demonstrations were given. It is interesting ‘to mote that even the "hams" were using a kitset receiver.

The "Hams" Display. ,_ [tHE AMATDUR transinitters ' ("hams") attracted a good deal of attention-it was one oi the most interesting stands at the exhibition. There were several transmitters, de signed to work on all amateur bands from 10 to 100 meters. One of these was crystal controlled-that of ZL 2AJ. It was a good outfit and its arrangement made thorough inspection possible. The transmitter of 2BP was used for transmission of messages from the hall, for the "greeting" arrangements that have featured in other centres were made available to the visitors. It was possible for a visitor to send ereetings to a friend in any part o the world. These address:s (for the greetings were standard) were transmitted on low power to another station in Wellington. .nd there dispatched to stations in the oth centres, From here the message was phpned or sent to the person to whom/ they were addressed. In the case or over seas friends the messages would b transmitted when the opportunity 0 contacting a ham in that country ocenrred. The stand was staffed hy hams wh were readv to answer the questions of those who sought information. » Other Exhibits. HE Post and Telegraph Depart ment had on view a carrier curren telephone apparatus used to provid additional channels over the existin circuits. It is the system of wired wireless, which has become popular overseas. The apparatus is used b; the Department for long-distance calls. . . The "Radio Record" was repre sented. For during the latter part o the exhibition the Technical Wditor was present to discuss problems. I is perhaps significent that oniy abou half a dozen queries were raised anc most of those dealt with power an¢ a.e. questions. Last yea: the positio was very much different and the tech nical editor had hardly a spare minut during the busy times.

General Impressions. QNE was left with the general i pression that radio has at las reached some degree of stability. I is again coming to the pockets o those who cannot afford to pay ou big sums for entertainment but thi time it is reliable and, equally, i portant, it is musical. A fairt de gree of realism has been achieved an¢ the sets are sensitive. The combination with the gramo phone has been a happy one, and bot! means of entertainment are showin

Next Week 1S Music Week

great progress. The amateur enthusiast is rapidly vacating the field and is becoming a "ham" or buying an electric set. The radio business is passing from e small expert dealers to the music houses, who are employing specialised service men to look after the sets when roncé they are installed. Technical questions are not asked by the buying public so that the salesmen are no longer versed in the technicalities of radio. Probably for this reason the writer was told that a certain receiver ased three stages of 245 in the rf, amplifier. .