Electronics-World-1959-05
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18<br />
NEW BLONDER -TONGUE<br />
VHF ANTENNA BOOSTER<br />
MODEL AB -2<br />
for clear, sharp TV pictures in<br />
weak signal & fringe areas -more than<br />
10 db gain on all VHF channels<br />
$53.95<br />
NEW BLONDER -TONGUE<br />
FM ANTENNA BOOSTER<br />
MODEL AB -FM<br />
for superb FM listening pleasure in<br />
weak signal & fringe areas -more than 16 db<br />
gain over the FM band (88 -108 mc)<br />
$53.95<br />
new frame grid tube provides lowest noise<br />
figure for brilliant reception<br />
maximum signal -to -noise ratio -ideal for<br />
new receivers<br />
remote control via power supply at, or<br />
near receiver<br />
internal multiplex circuit - single lead line<br />
carries AC power 'up' and signal 'down'<br />
easy mast mounting close to the antenna<br />
boosts signal before line loss can develop<br />
swing -down chassis for easy service and<br />
maintenance<br />
no -strip terminals for speedy, secure<br />
installation -<br />
yet<br />
REMOTE CONTROL UNIT<br />
NO- STRIP' TERMINALS<br />
A Fir %lnbh through rarl,a c77sir1To,tor :c or v'rifc direct: ENV-5<br />
BLONDER -TONGUE LABORATORIES, INC.<br />
9 Ailing Street Newark 2, N. J.<br />
In Canada: Telenuipment Mfg. Co., Ltd., London, Ont. Export: Morhan Export Corp., N. Y. 13, N. Y.<br />
hi-fi components UHF converters master 7V systems industrial TV cameras FMAM radios<br />
countered. With the advent of summer,<br />
we also ran into some temperature<br />
difficulties. Since the pulse counter<br />
output is very stable, any change in<br />
meter reading must be caused by a<br />
change in transistor gain or collector<br />
leakage. This latter will cause the<br />
meter to vary, but only if the current<br />
is large in the first place.<br />
Several types of recent transistors<br />
are rated at only 1 or 2 µa. leakage.<br />
One of these transistors would probably<br />
help greatly.<br />
If leakage current at high temperatures<br />
is still noticeable, especially if<br />
you are using a sensitive meter, it %%1ll<br />
help to reduce the meter sensitivity<br />
with a shunting resistor and increase<br />
the setting of the calibration control<br />
to restore proper calibration. Start by<br />
turning the calibration control all<br />
the way up. Then find a value of<br />
resistance that will reduce the meter<br />
sensitivity so that the tachometer<br />
indicates about 10 to 20 per -cent high.<br />
Install this resistor and then reduce<br />
the calibration control to give proper<br />
indication.<br />
Should you find this modification<br />
necessary, I would suggest that you reduce<br />
resistor R from 8200 ohms to<br />
3900 ohms before performing the above<br />
adjustments. This will increase the<br />
drive to V. and allow the meter to be<br />
shunted even more. At the same time,<br />
you should reduce resistor R. to 200<br />
ohms to prevent saturation of V_ at the<br />
higher current level.<br />
RICHARD H. SMALL<br />
Alta,lena, ('nliforni:1<br />
IMPORTANT NOTES ON OUR<br />
CITIZENS BAND TRANSCEIVER<br />
article "Build This Citizens Band<br />
TIIE Transeeicer" b. Don Stoner in<br />
)larch, <strong>1959</strong> issue attracted considerable<br />
interest. The following two l t.<br />
sl hi bare been made in the article.<br />
First. when testing or adjusting the<br />
transmitter with its dummy load lamp,<br />
no Iir4.ns4. is required since useful radiation<br />
will not occur. Such adjttsam4.nt<br />
mar not be made with the transmiu, r<br />
radiating into its antenna unless Ih,<br />
are ender the suierris' of a licensed<br />
commercial radio operator.<br />
Second is the matter of the cr.stal to<br />
he used in order to meet the required<br />
.0<strong>05</strong>% frequency toleranre. We Lave<br />
just learned that International (:r.-tal<br />
is not certif.ing its FA-type cr. -tal- at<br />
.0<strong>05</strong>% but instead is offering a "packaged"<br />
unit. l'0-27. which is a 1111.14.1,<br />
wired with a 6A1.6 lobe and instal.<br />
This unit. which may be used as the<br />
r.f. section of the transeeiser is available<br />
f the a pan, at 18 North Lee aye.,<br />
Okla! a (:it,. Okla. for $14.95.<br />
Suitable erystals are also available<br />
front other source.. In such cases be<br />
sure to specify a frequency tolerance of<br />
.0<strong>05</strong>% and inform the manuLeelurer<br />
of the circuit in which the er.slal is<br />
to he used. This is important since the<br />
precise operating frequency will depend<br />
on the circuit capacit, which appears<br />
across the cr,stal.<br />
It is interesting to note that the FCC<br />
would like to see the Citizens Band put<br />
into use "with a minim of restricting<br />
regulation." [lope to see sou on the<br />
Citizens Band soon. 30-<br />
ELECTRONICS WORLD
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