14

RAMBLING from 13

ness for about a decade, their radio battery busi- ness was a very important part of their revenue. The technological development described in the next para- graph virtually demanded the introduction of this previously unavailable battery size. The real technological

development came from RCA, one of the major vac- uum tube manufacturers. In 1939, Sylvania, another major manufacturer of vacuum tubes, had intro- duced a new line of tubes designed for portable radio use. They were as small as other tubes available at that time, but operated at a filament voltage of 1 ½, with very low current drain, therefore, intended and ideal for battery use. The low current drain of these new Sylvania tubes was a breakthrough in itself. RCA’s new tubes embraced the Sylvania low current technology, but added a new dimension. (Pun intended.) RCA’s new tubes were what were to become known as min- iature tube types. (See

THE WEIRS TIMES, Thursday, March 25, 2010

accompanying photo to compare tube sizes.) Ze- nith seized the opportunity presented by Eveready’s new battery and RCA’s new low current drain, miniature tubes. Radio manufacturers,

such as Zenith were in to- tal reliance of tube manu- facturers for new tube de- velopments, as Zenith and many of its competitors did not produce vacuum tubes. When a tube sup- plier introduced a new line of tubes only then could Zenith engineers or those of its competitors begin engineering sets that utilized the new tube developments. The Zenith “Pockettradio” that is the subject of this article is a good example of how the radio industry worked. This article’s subject ra-

dio made very efficient use of the new battery and tubes as well as other new components that were as well reduced in size to achieve the goal of an extraordinarily compact radio. As an accompany- ing photo illustrates, there is virtually no space inside the radio’s cabinet that

Back in 2002 when this picture was taken, soup cans were soup cans and radios were radios!

goes unutilized. This author has experi-

ence with many radios that use the same four tubes utilized by this Ze- nith, most of which had larger components, cabi- nets and, as a result, larg- er built-in antennas. Most of the aforementioned ra- dios have fair to mediocre

tubes and circuits, have larger antennas and oper- ate on AC house current, not small batteries. Sta- tions several states away came booming in. Audio quality, especially for a small set, is very impres- sive and clear. It is evident to this author that the en- gineering in this radio is superb. Thanks to Al, this interesting piece of radio history has gone from a dormant object of interest to a functioning radio that will continue Rambling Through History, at least as long as Eveready is courteous enough to con- tinue to make their #467 battery. [2002 excerpt ends] Well, we’re back to 2010,

and Eveready is still being courteous enough to make

The radio tube on the left is a “newly” (1939) developed tube for use in battery powered portable radios. The earlier tube on the right has the same electrical characteristics, but is much larger. The egg is for size comparison and has been eaten since the photo was taken.

performance. Therefore, my expectations for this radio’s performance were low. I brought my gift home

from my garage, and robbed my Emerson’s #467 battery so that I could try the Zenith. The Zenith didn’t even meet my low expectations! That’s because it did not work at all. Tubes are only infrequently the culprits in old radios that do not function. But I tested the tubes and found that a type 1R5 was completely dead. I replaced that dead tube and re-soldered a broken connection and the Zenith came to life. In fact, a better choice of words would be, “it burst to life.” This Zenith performs bet-

ter than many radios that are larger, employ more

the #467 battery available. It’s pretty pricey; I just bought a fresh one for my presentation of the set on WBCQ. It’s kind of reas- suring to find some things that do remain available. In fact, I’ll be available again when we next go Rambling Through His- tory!

Note: The author, Mal

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