Download The DECIMETER slipslick

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The DECIMETER
slipslick
The Decimeter Slipstick fills a real need for the first
time ... it gives quick accurate frequency readings on
oscillators, receivers, or transmitters.
The Slipstick is
manufactured by UHF specialists, specifically for the
UHF spectrum, using UHF techniques.
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The Slipstick has an enormous range90 to 3000 Me
Rapid, direct-reading scale
2% accuracy or better
Versatility-measures received signals
as well as transmitter and oscillator
frequencies
Polystyrene insulation for low
loss and permanence
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Sturdy construction
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High-Q polished
silver finish
The DM-I03-W Slipstick Wavemeter is a
sturdy every-day tool
for the engineer and
experimenter.
Due to
its unique design and
construction, there are
no spurious responses.
The DM-I03-W has two modes of
resonance. The low-frequency mode
covers 90 to 400 megacycles and operates with a voltage maximum at the
end covered by the small square
plastic assembly. The high-frequency
mode operates with a voltage minimum near the square plastic end and
responds from 350 to.3000 Me. Above
700 Me., two or more resonant points,
separated by a half-wavelength, will
be found. Always read the highest
frequency response.
USING THE SLiPSTICK
IS EASY
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Usia the "slipstick" is easy
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To measure the frequency of an oscillator, place the
square plastic end of the Slipstick in the r. f. field.
Slide the center rod until a sharp reaction is seen on
the oscillator. This reaction will appear as a fluctuation of grid current, plate current, or output to an r. f.
detector. Reduce the coupling of the Slipstick to
the oscillator until its effect is just perceptible. Read
the frequency at the outside edge of the center
plastic assembly as marked.
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To measure the frequency of a received signal, couple
the DM-l 03-W to the antenna circuit. A sharp fluctuation of output from the receiver will occur when the
Slipstick is tuned to the incoming signal. Do not
confuse this indication with a reaction on the receiver
oscillator, which may be nearby .
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In the event that the frequency of the source to be
measured is not known with sufficient certainty to
determine which of the two Slipstick scales to read,
proceed as follows: If the high frequency scale reads
700 Me. or over, another response may be found at
approximately half the scale reading. If it is found,
the higher frequency reading was correct; if not,
read the low frequency scale.
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c
TO
MEASURE
FREQUENCY
OF AN
OSCILLATOR
TO
MEASURE
FREQUENCY
OF A
RECEIVED
SIGNAL
IF
FREQUENCY
OF SOURCE
IS NOT
KNOWN
If the high frequency scale reading is less than 700
Me., set the DM-I03-W to resonance in the circuit
and touch one of the silver rods with the tip of a lead
pencil just outside of the square plastic assembly.
If a considerable reaction on the resonance is noted,
read the low scale; if little reaction, read the high
scale. REMEMBER, this procedure is necessary only
if the frequency is not even approximately known in
advance, and only when the signal source is known to
be capable of supplying either high or low frequency.
I.MATEUR
N~T PRICl:
$16.50
FINDING
PROPER
SCALE
READING
IS
SIMPLE
FOIl AMATEURS
ITislMPIEI
To
transmitter,
plug
a 13 em.
a 2C40 tube into the DM-240-A
oscillator, make filament,
tions-you're
make
plate and antenna connec-
ready to go!
I"EAII'!
To make a recei'Yer, use the DM240-A oscillator as a superregen detector in the usual separatequench circuit.
Or use it as the H. F. oscillator in a superhet!
IT' FUN!
new phenomena
these frequencies.
New DX records are waiting to be made;
are to be disco'Yered; new uses are to be found for
TECHNICAL DATA ON DM·240·A OSCILLATOR
FEEDBACK
CONSTRUCTION
A small feedback loop is built into every DM240-A oscillator.
This loop extracts a small
amount of energy from the grid-plate dircuit
and couples it into the grid-cathode circuit. The
amount of feedback is controlled bv a shaft on
the side of the oscillator. No adjustment of this
control is necessary for receivers over the whole
tuning range. For transmitting,
it is adjusted
to obtain maximum plate efficiency.
The DM-240-A oscillator is constructed of brass
throughout with heavy silver plating overall to
assure low r.f. losses, low contact resistance and
long life. The outside is finished in a lustrous
brown wrinkle to afford maxi mum heat radiation
and consequent low plate seal temperature. The
oscillator is assembled by high precision methods
to provide absolute concentricity of contacts,
eliminating tube strain and providing maximum
r.f. efficiency.
High-frequency power is taken from the oscillator by attaching a piece of RG-8jU or similar
cable to the output coupler at the top of the
oscillator. The output coupler may then be
rotated and locked in the position to give maximum output. As a receiver, the same procedure
is followed and the coupling adjusted to give best
sensitivity. If desired, a dipole antenna may be
attached to the oscillator without intermediate
cable. The power output of the DM-240-A oscillator is sufficient to assure communication over
any line-of-sight distance.
The DM-240-A oscillator consists of two major
tuned coaxial circuits. One circuit is from grid
to plate and the other is from grid to cathode.
Both circuits are electrically
three-quarters
wave-length long and are carefully proportioned
to suppress spurious modes of oscillation. Firm
slotted connectors provide excellent contact to
the 2C40 tube, and maintain the high Q of the
coaxial lines.
POWER REQUIREMENTS
The filament of the 2C40 tube operates on 6.3
volts a.c. or d.c. at a drain of only 0.75 amperes.
The plate supply is 250 volts, 20 ma. maximum.
The low drain of the DM-240-A oscillator makes
it ideally operated from the power supply of any
automobile receiver, or from light-weight batteries.
FREQUENCY RANGE
The nominal tuning range of the DM-240-A is
from 2000 to 2500 Mc. Due to small variatl0ns
among 2C40 tubes the range may be slightly different, but will never be more than 25 Mc. off.
All oscillators are guaranteed to cover the amateur band from 2300 to 2450 Mc.
Since the DM-240-A is a triode oscillator, any
modulation method ordinarily used with triodes
is satisfactory. Heising modulation using a 6V6
or 6F6 is simple and effective.
Both r.f. circuits are tuned by screw-type capacitors inserted at a voltage "loop" in each circuit.
Standard quarter-inch shafts protrude from the
oscillator housing so that any type of knob may
be attached conveniently. The grid-plate tuning
is the primary frequency adjustment. The gridcathode tuning is relatively broad, and need be
altered only when large frequency ranges are to
be covered. Due to the vernier effect of the
screw-type tuners, setting of the oscillator frequency is easily done without fussy "hair-line"
tuning.
ANTENNAS
One of the greatest advantages of 2400 Mc. operation is the tremendous power concentration
possible with directional antennas of small size.
Yagis, stacked arrays, rhombics, parabolas and
corner reflectors are constructed with little effort for this frequency, and power gains of 20
to 100 are easily realized. Since a dipole is only
2f' long at 2400 Me., the small size of a directional antenna can be readily visualized.
Look for these Decimeter products coming soon
DM-240-F -Precision
DM-120-A -Oscillator
DM-120-F -Precision
DM-I03-W-Reaction
DECI
Wavemeter for 13 cm. band.
for 25 cm. band.
Wavemeter for 25 cm. band.
Wavemeter for 100 to 3000 Mc.
M ETER
I.' ]
c.,.;
INC.
1430
MARKET
ST.,
DENVER
2,
COLORADO,
U.
S.
A.