he "Airzone" Portable

Radio Record, Volume II, Issue 47, 7 June 1929, Page 9

he "Airzone" Portable

A, SMYTH & CO. have submitted to us the Airzone Portable, ' It has been given an extensive test, and the results are very pleasing. The receiver is made up in a neat carrying ease approximately 2ft. by 18in. by 6in., and weighs 27lb. The circuit is the well-known Browning-Drake _ fourvalve (RF, detector and two audio). The filaments are heated from dry "A" cells carried within the case, and the "B" battery 90 volts is similarly concealed. The speaker is a magnetic cone of the best type. ‘It has a substantial magnet that is altogether greater than the usual for this type. It is thus capable of reproducing a very wide nge of musical frequencies. 1A loop antenna is concealed in the lid. To this there are three terminals, ®wvo of which connect to the set directly, and a centre tap to which to connect an aerial when it is desired to work with this. Wnder these circumstances, an earth is. connected to the lower terminal. This antenna has marked directional properties, and is particularly sensitive. From 2YA working on the loop, it was found that volume unless controlled was excessive. It lacked nothing in quality, and compared very favourably with the straight-out' Browning-Drake. With the loop, the set is highly selective. It was possible, while 2YA was operating, to tune in 1YA and 8YA without: background, and at. good strength. 2B, and 2FC were likewise brought in while the local station was operating, though the latter was somewhat weak and had a background. ‘The set was tested during one of the wofxst weeks as far as static interferenge is concerned that has been experienced for some considerable time, so that almost all testing had to be done on the loop alone. The tests were carried out during the search for the Southern Cross, and it was found that this receiver was to be preferred to one using an aerial and an earth under these’ conditions, ‘Every evening 2BL was tuned in and could be heard right through his session at perfect speaker sjrength, It was'a treat to be able to obviate the static, and herr the latest authentic news: of the airmen. 8LO was heard from the Yop, but its strength depended very much on atmospheric conditions. On one evening only was the set able to be tested from an aerial, and this fortunately was Wednesday. 1YA, SYA and 4YA were tuned in at perfect

speaker strength during the latter afternoon and early evening. In addition, the following stations were brought in at excellent strength: 2UR, 2GB, 3LO, 3UZ, 4QG, 5CL, 2F0, 8AR, 7ZL, JOAK and JOGK. The portable thus equalled the ordinary four-valve Browning-Drake.