THE LISTENERS' GUIDE

Radio Record, Volume I, Issue 48, 15 June 1928, Page 13

THE LISTENERS' GUIDE

SPECIAL INTEREST TO CONSTRUCTORS ONSTRUCTORS and experimenters will find the "Listeners’ Guide" extremely handy for general reference for lists of New Zealand, Australian, American and Canadian stations, with power and wave-lengths, short-wave stations, and a wide range of other information. Of special interest to constructors there is a list of practically all valves on the New Zealand market, showing at a glance their main characteristics and the positions in the set for which each valve is best suited. There is also a table giving the necessary. gridbias for any valve likely to be used in audio stages. mee ANOTHER useful list is that of rectifying valves that are sold without the stipulation that the purchaser must be in possession of the charger for which they are designed. Valves for B battery eliminators and A battery charging are also included, full particulars of all the rectifiers being given. : THER tables include winding of solenoids for given wave-length ; turns for spider-web coils to tune with condensers of different capacities; turns for secondary coils tuned with condensers of various capacities; tables for making fixed mica condensers of capacities from .5 mfd. down to .00015; wire tables; list of amateur transmitters, ete. ONSTRUCTIVE articles include erystal receivers, with the "R.R." Selective Crystal Receiver, which so Imanv constructors have found highly

successful, and which makes a highly effective wave-trap, Then there are two amplifiers for the erystal, a oneand a two-valve. . The ever-popular four-vyalve, Brown-ing-Drake is fully dealt with, including the amplifying for which inquiries are coming to hand in connection with the two BR.F. tuning unit. The "Record" short-wave receiver is fully described, both as a complete shielded three-valvye receiver, and asa one-yalve "eonyerter" or "adapter," which can be plugged into the detector socket of any broadeast receiver and thus use the audio amplifier to increase the volume of the short-wave ‘reception. Otfhar information ineludes the Gov-

ernment regulations relating to wire-| less listeners, a handy glossary of -yadic terms, ete. The "Guide" can be obtained from your dealer for 2s. 6d., or 2s. 9d. posted from the "Record" office.