LM Series Crystal Calibrated Frequency Indicating Equipment
NAVY MODEL LM SERIES
CRYSTAL CALIBRATED FREQUENCY
INDICATING EQUIPMENT
Navy Model LM-15 Crystal Calibrated Frequency Indicating Equipment
FUNCTIONAL DESCRIPTION
This equipment provides a simple and reliable frequency indicating
source between 125 kc and 20 mc for frequency setting and measurement of
receivers, transmitters, signal generators, or any electronic devices where
the frequency must be known. It is a heterodyne type of unit having a variable
oscillator which may be point-checked against an internal crystal oscillator
and its harmonics at frequent settings. An external signal may be mixed
with the variable oscillator output by a wire or antenna connection to
a binding post. A jack provided on the front panel permits the use of phones
for listening to the heterodyne. The variable oscillator signal may be
internally modulated.
RELATION TO OTHER EQUIPMENT
This equipment will be superseded by Frequency Meter FR-4/U. The
various models of LM Series Equipment fall into three categories, according
to their power supplies, as follows:
MODEL POWER INPUT MECHANICAL DESIGN REMARKS
i. Self-contained batteries
LM-13 Self Contained Same as LM-1O less Mounted in Type
Batteries shock mount base CRR-1O111
Carrying Case
with Batteries
LM-17 Self Contained Same as LM-10 Mounted in Type
Batteries CKB-10111
Carrying Case
and CKB-10110
Canvas Bag com-
plete with
batteries
ii. DC supplied from other equipment
LM-10 12/14-24/28 Minor Mechanical LF Het. Osc. fund.
200/260-260/475 revisions freq. changed
LM-12 12-14/24/28 Same as LM-l0 Included in Type
200/260-260/475 CRR-10086 Water-
proof Carrying
Case
LM-14 12/14-24/28 Same as LM-10
200/260-260/475
LM-16 12/14-24/28 Same as LM-10 Included in Type
200/260-260/475 CKB-10086 Water-
proof Carrying
Case
LM-19 12/24-24/28 Same as LM-10 Included in Type
200/260-260/475 CRR-10086 Water-
proof Carrying
Case
LM-20 12/24-24/28 Same as LM-10 Included in Type
200/260-260/475 CRR-10086 Water-
proof Carrying
Case
iii. AC operation with rectifier unit
LM-11 Rectifier Power Same as LM-l0
Unit CRR-20104
or CRR-20104A
LM-15 Rectifier Power Same as LM-l0
Unit Type CKB-
20104 or CKB-20104A
LM-18 Rectifier Power Same as LM-10
Unit CRR-20104A
ELECTROMECHANICAL DESCRIPTION
POWER SUPPLY.- Self-Contained Batteries, i: 12 to 14 v dc, 0.6 amp
or 24 to 28 v, dc, 0.3 amp and 200 to 26O v dc, l0 ma or 260 to 475 v dc
30 ma.
External DC Supply, ii: Same as for i above.
Rectifier Power Unit, iii: 105 to 125 v ac, 60 cps, 27 w.
FREQUENCY COVERAGE.-
Range: 125 to 20,000 kc.
Fundamental: 125 to 250 kc and 2000 to 4000 kc.
Crystal Oscillator: 1000 kc.
Modulation: 500 cps.
Accuracy: +-.02%, 125 to 20,000 kc; +-.01%, 2 to 20 mc between
-32 degrees and +65 degrees C ambient temp.
PRESENTATION AND CONTROLS.-The drum and disc dials are precision
ganged for accurate frequency readings. A panel trimmer is provided for
setting the variable oscillator at any check point by heterodyne with the
crystal oscillator or its harmonics. A head phone jack for a 600 ohm audio
output is mounted on the front panel.
FITTINGS AND ACCESSORIES.-The rf coupling terminal is a single binding
post. A Navy Type 49025 Telephone Jack is used.
CONSTRUCTION.-The waterproof carrying case provided is made of aluminum
with an olive drab wrinkle finish. The frequency meter case is made of
aluminum with a black wrinkle finish.
MANUFACTURER'S OR CONTRACTOR'S DATA
Bendix Radio Division, E. Joppa Rd., Towson 4, Md.
Contract NXsr-23485, dated 2 June 1943.
Contract NXsr-33637, dated 30 June 1943.
Contract NXsr-40987, dated 9 November 1943.
TUBE AND CRYSTAL COMPLEMENT
(1) 76 (1) 77 (1) 6A7
(1) Oscillator crystal type CRR-40023B
REFERENCE DATA AND LITERATURE
NAVSHIPS 900,217-1B: Handbook of Maintenance Instructions for Navy
Model LM-19 and LM-20 Crystal Calibrated Frequency Indicating Equipment.
TYPE (USAF):
CLASSIFICATION: (NAVY):
(ARMY): Not Classified
STOCK NO.: (USAF):
(NAVY): LM-10: F16-Q-160976-200
(ARMY): LM-1l: F16-Q-160480-200
LM-12: F16-Q-160482-200
LM-13 F16-Q-160484-200
LM-14:
LM-15: F16-Q-160488-200
LM-16: F16-Q-160490-200
LM-17: F16-Q-160492-200
LM-18: F16-Q-160494-200
LM-19: F16-Q-160496-200
LM-20: F16-Q-160498-200
(ARMY):
DESIGN COGNIZANCE: Navy, BUAER
PROCUREMENT INFO.:
PROCUREMENT COG.: Navy
RDB IDENT. NO.: 2.1.3
F.I.I..N.:
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