TELEVISION NUMBER - AmericanRadioHistory.Com

www.americanradiohistory.com
48d
Radio News for November, 1928
Better
Contact
Powerful
Tension
BaneryCltp
rOWLarpL TINe1011
for an
uninterrupted
flow of
Electrical
Current
Grip -Tite Battery Clips assure
RHANCO better contact. Hundreds of thousands
have been sold and are giving complete satisfaction
today. Here's the reason. The design
is right and assures free and uninterrupted
How of electrical current.
There are no springs to heat up or burn or
drop out.
Shanco Grip-Tite Battery Clips are acid -
resisting and are made of special powerful
tensioned tempered spring steel, solidly
riveted together. ALL parts are electro-plated
before assembly (not galvanized nor tinned).
The jaws open wide and are easily applied.
Grip -Tite Bulldog Teeth "stay put" and
bite right through corroded bars and
terminals. The teeth are so arranged that
the clip cannot fall over and short the battery.
Here is a compact, solidly built battery clip
that is a big value and a permanent investment.
There are four sizes for every battery
need. Five ampere, fifteen ampere, fifty
ampere and three hundred ampere.
ILMail the coupon at once for our special
low prices and complete information.
SHANKLIN MFG. CO.,
Dept. 72, Springfield, Ill.
Gentlemen:
Please send me complete information on your
special Radio Battery Clips. No obligation,
of course
Name
á
Address
City
State
DABLE "B" BATTERY POWER
100 Volt Edison Element.
Non -Destructive. Rechargeable "B" Battery with
charger. Shipped dry, with solution. 812. 140 Volt
with charger. 517. 180 Volt Power Unit. with
Trickle Charger. 824.00.
SEND NO MONEY -PAT EXPRESSMAN
Write for ear Free Literature
SEE JAY BATTERY CO., 915Breok Ave.. New York
Eavox
Makers
of high
d
quality
resistors and
condensers that are
Built Better - to endure.
Write for The Research Worker.
A free monthly publication.
AEROVOX WIRELESS CORPORATION
68 Washington Stre t Brooklyn, N. Y.
Please
Sensitizing the R. F. Amplifier
(Continued from page 453)
duces distortion. However, the potentiometer
may be removed, the grid return
changed from the movable arm of potentiometer
to minus filament, and a variable
resistor (of 200 -500,000 ohms range) inserted
in the plate circuit. An increase in
selectivity will be noted, while the plate current
drain will be materially reduced.
REMODELING THE NEUTRODYNEe
The neutrodyne circuit may be rendered
more sensitive by removing the neutralizing
condensers and controlling the R.F.
stages with a suitable variable resistor,
placed in the plate circuit. Radio enthusiasts,
anxious to secure real distance with
neutralized sets, have sometimes replaced
the fixed neutralizing condensers with tiny
variable condensers, together with a suit -
able indication to show the normal adjustment
for each condenser. A simpler method
is to employ variable plate voltage, as mentioned;
for then a single control takes care
of the entire R.F. amplifier.
Lately the grid -suppressor method has
come into wide favor. This comprises a
200- to 1800 -ohm fixed resistor, depending
on the circuit conditions and the tube,
placed in the grid lead of each R.F. amplifier
tube. The grid -suppression effect of
a given resistor becomes more marked at
higher frequencies, or lower wavelengths,
which is a most desirable feature, since the
tendency of most R.F. amplifiers to oscillate
increases with frequency.
WHEN TIME WAS MONEY
LABaY: "They say it cost $1.15 a second
to broadcast the Democratic National Con
vention."
SANDY: "Gee! what a.spendthrift that announcer
was, with his "Stand by one moment,
please' ! " -ITrm. G. Mortimer.
HOME, JAMES
There was an announcer named James,
A favorite indeed with the dames:
But they all had to smile
Every once in awhile
When they heard him pronounce foreign
names.
-Mrs. Fred W. Auroache.
TO ERR IS í
'NE LN00t
RApAto tXOE0.T C. l
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ANO AFTtRNololNg You MIA/woo FOR AN NOuR WITN,HCOntTIOAL DET,M1r
AE Acoto sets Tax 4t Wal NOW Slut A DtMON;TWNTION OF OM VET eAntV11-
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-Ax0 AFy-n 101Cau /VW, aLTwN N RAt,Ñ TTjTut TUBES/
Oe NICE wt AE TINOS TuNT.
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uFxJt2tEn.E-ÌAAT 6QAND ANS (fLORIOOS fEEl.IN6!
-The Wireless Constructor, London.
say you saw it in RADIO NEWS
PF-250
Power Transformer
for
UX 250 Power Tubes
A husky transformer built for doing the
job, not for looks. The PF -250 is rated at
1200 -600 volts plate, 75h volts power tube,
73i volts rectifier tube filament. Center
taps are provided on each of the filament
windings. Continuous rated capacity of
plate windings, 160 MA., continuous rated
capacity of each 755 volt winding,
3 Amperes. DC plate output with
two U X 281's full wave, up to
450 volts with sufficient excess
for "C" Bias.
Ask for Bulletin No. 1033 describing
fully the PF250.
Price, each -- $30.00
S'ghtly bigler aQ,t of Rod, Mnunr.in,
American Transformer Co.
Tas former Builders for more thon rt Ymir
263 Emmet St., Newark, N.J.
DYNATONE DYNAMIC AND
MAGNETIC REPRODUCERS
Write for information on the new Dynatone
40 -cycle reproducer. Brings out bass and
depth from any set. Full dynamic movement.
Dynatone Electromagnetic Units ....$12.50
Complete with 7 -in. Cone and Baffle. 18.50
Sold under 10-day money -back guarantee.
Send check or money -order in advance or
pay postman.
ALSO
Complete set of blueprints and instructions
for building your own DYNAMIC moving
coil unit. with cone and baffle. New design
makes home construction simple with few
tools. Guaranteed to work. Sent postpaid
anywhere upon receipt of $1.00.
FANSPEAKER RADIO COMPANY
74 DEY STREET - - NEW YORK, N. Y.
Wholesale
Prices
Everything in radio -kits, parts,
accessories, sets. Improved designs
and styles. Big selection at
worthwhile saving. Immediate
service; personal attention. Send
for complete, illustrated Catalog
"B-1."
711 W. LAKE STREET. CHICAGO