RADIO

Rotorua Morning Post, Volume 2, Issue 515, 26 April 1933, Page 5

RADIO

• # . I (Notes h'y "Tfiode.")' I ; Receptibh at th'e early part 'of last ] week was iair," but static was trouble- j lorne .at the week-end. / ! On Sa'tufday aftem'oon 3YA came i in early, and by. J p.m. was almost as loud as 2YA, v/liile several Americans "Were easily picked up hefore'b p.m. These were received oh a small t,or.'f. set, so that owners of big superhets ■ should have had a good afternoon ; picking up th'e di'starit stations in dayt light. | It .s only recently that English manufactureris have made a definite attemp't to secure a fair share of business in overseas markets. In the past they wiere content to make two, three and in some cases four-valve jobs, which were quite unsuitable for New Zealand conditions. Several firms now produce six and seven-valve models, which ia,t present are for export only. It is dnteresting to note. the increasing number of what miglit he termed super sets that are coming on to the AmeriCan niarket. Battery isets and available using as many as 10 2-volt valves, wh'ile the a.c. models use up to -16 valves. The hame "Silver Mar.shall" is a hou ehold word amongst radio listenens, and their latest 15valve set is oue th'at many of us would no doubt like to own.

It ds interesting to note that Mr. Silver has not ma.de use of dual speakers cr class B amplificatdon, both of which are so popular in America to-day. The single speaker is of special desd'gn and weighs 421b. The audio side of the set is prime class A, uing 59' in push-pull. The designer objects to the new 83 mercury vapour rectifier and has used two 89's in parallel. Some of the new tubes on the market are meeting with a mixed reccption from Auckland manufacturers. Th'e writer has been informed hy two firms that the 5-9 used as a single pentode out put has not come up to expectations. A more startling statement was made by the branch manager of a firm who are known in the radio business throughout the world. He stated that his firm were not using any of the new fifty series valves, claim'ing that they ara not so stable in operation. However, there are many satisfied owners of isets using the fifty series valves and no doubt many of them have come to stay. A new valve of intersst is the ER-25-Z5. It is the same size as the fifty series and has the now famildar dome top. It eonsasts of a heater, two plates, and two ca.thodes, and fits the standard six-pin hase. It has a 25 volt filament and' with' llv. a.c. input has a d.c. output of approximately 100 m, amps. .a,t 160 volts. The output current is not much below that of a 280, hut the voltage is on the low side. Howiever, with suitable valves it may be possible ot produce small transformerless sets to work from tbe mains in Rotorua. As the maximum dnput volts p'er anode is 135, it would rnean .a, step-down transformer out o^ the town area, and it is considered doubtful df the valve will ever be used very much in this. country. Little progress is being mada in New Zealand with the sale of automobile radio sets. This is another phase of the radio trade in which America leads the world. It is now standard equipment on many of their cars, and last year over 160,000 sets swere sold. While we cannot expect to see much progress made in the eountry districts until the more powerful stations are on the air, one would expect to find radio equipped cars popular in the maiin centres. A full ran'ge of special automobile type valves are now available and eomplete sets shculd be popular with service car proprietors and camp'ers. Th'e Rotorua Public Address equipment was in nse at the Ngongotaha isports on Easter Monday and although only op'erated at half volume announcements were1 elearly heard hy fishermen on the lake. Each' time this equipment has been used the operator has received repeated enquirdes as to if he could pick up some broadcast station, usually for the sporting results. The speaker units are designed to work under continnous load of 10 wiatts with a peak load of 25 watts. As 1 watt is more than sufficient for the average size room, the reader will have some idea of the enormous volume which these speakers can handle. Apparently th'e only sporting broadcast from the YA stat ons this week will he a running commentary on the Rughy match at Eden Park, Auckland. This will be broadcast. by 1YA at 2.45 p.m. on Saturday. A lecture on "How to Speak in Public" will be given by Mr. Mazengarb from 2YA at 8.42 on Friday, wliila Mr. Ackland will be heaxdiin "Inventions and Fabrications" from the same station -a,t 8.40 on Thursday.