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RADIO BROADCAST ADVERTISER
843
RESULTS!
Laboratory Data
THE following laboratory tests were made with the Penetrola on April 30, 1925. Measurements for volume and selectivity were taken with a General Radio Co. type 164 Audibility Meter, a precision instrument giving comparative values of signal intensity (the effect on the human ear is less than the actual differences recorded on the Audibility Meter;. Standard regenerative, tuned R. F., neutrodyne, super-heterodyne, reflex, etc., sets were tested.
SELECTIVITY TESTS
Receiver
Desired Station
Inter fering Station
Tuned R. F. Receiver 5 tube
WCAL Northfield, Minn.
WCBD
Zion
Without Penetrola
35
2 9
With Penetrola
2,00 0 —
2 tube Regenerative set
woe
Davenport
WMAQ, WEBH, KTW,
Chicago
Without Per.cTi'jir.
0
2.000 +
With Penetrnla
300
0
5 tube Tuned R. F. Receiver
CXRW Winnipeg
WGN Chicago
Without Penetrola
0
150
With Penetrola
1,300
0
Pep-up your present cRsecevverl
Its performance through the use of the Penetrola will astound you!
The following results are guaranteed on even the best sets:
1. Increase selectivity. A powerful aid in penetrating interference from local stations. Will positively bring in stations you can't get without it.
2. Increase range and volume.
See laboratory tests in column to left
Without the Penetrola Unit, CXRW, for example could not be heard, while WGN had a signal intensity of 150. With the Penetrola CXRW could be heard with a signal intensity of 1,300 while WGN was inaudible. Interference entirely eliminated.
VOLUME TEST
5 tube Tuned R. F. Receiver
Without Penetrola
With Penetrola
Desired Station
WOAI San
Antonio
2,000
Interfering Station
These figures show an actual increase of energy in the 'phone circuit of 188 times.
3, Reduce static by permitting use of short aerial while actually increasing signal intensity.
4c Improve quality by making it unnecessary for you to operate your set close to the oscillating (howling) point.
5o Positively stop your set from radiating to the annoyance of neighboring fanso
The Penetrola will add more in performance than many times its cost invested in a new set. In most cases your new combination will out-perform the best set on the market.
Jobbers and Dealers: Write for discounts
W ALBERT MANUFACTURING CO. 927 Wrightwood Ave., CHICAGO, U. S. A. '
9** lew
Two types : (a) for antenna sets, (b) for loop sets. Easily installed — no alterations whacever. Equipped with standard Walbert parts: Univernier, UnivernierCondenser, Low-loss Socket, Low-loss Inductance, Isodon, Colored Connection Cords. Finished in black crystalline enamel blending with any cabinet. Price £35.00.
All Walbert Products protected by Pats, or Pats. Pend. U. S. and Foreign.
FREE Write for laboratory bulletins describing any Walbert product in which you may be interested.
^ Tested and approved by Radio Broadcast -^r