Cobra 148gtl Guía De Operación
RECEIVER
Sensitivity
SSB: 0.25
µV for 10dB (S+N)/N at greater
than 1/2-watt of audio output.
AM: 0.5
AM: 0.5
µV for 10 dB (S+N)/ at greater
than 1/2-watt of audio output.
Selectivity
AM: 6dB @ 3 KHz, 50 dB @ 9 KHz.
SSB: 6 dB @ 1.1 KHz, 60 dB @ 2.3 KHz.
SSB: 6 dB @ 1.1 KHz, 60 dB @ 2.3 KHz.
Image Rejection
More than 65 dB.
IF Frequency
AM: 7.8 MHz 1st IF, 455 KHz 2nd IF.
SSB: 7.8 MHz.
SSB: 7.8 MHz.
Adjacent-Channel Rejection
60 dB AM & 70 dB SSB.
AM and SSB RF Gain Control
40 dB adjustable for optimum signal
reception.
reception.
Automatic Gain Control (AGC)
Less than 10 dB change in audio
output for inputs from 10 to 100,000
microvolts.
output for inputs from 10 to 100,000
microvolts.
Squelch
Adjustable; threshold less than 0.25 µV.
ANL
Switchable.
Noise Blanker
RF type, effective on AM and SSB.
Voice Lock Range
±2.5 KHz.
Audio Output Power
4 watts into 8 ohms.
Frequency Response
300 to 2500 Hz.
Built-in Speaker
4 ohms, round.
External Speaker (Not Supplied)
8 ohms; disables internal speaker
when connected.
when connected.
PA SYSTEM
Power Output
4 watts into external speaker.
External Speaker for PA (Not Supplied)
8 ohms.
(SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE)
Section II Specifications (Cont.)
4
Section II Specifications
GENERAL
Channels
40 AM, 40LSB, 40 USB.
Frequency Range
26.965 to 27.405 MHz.
Frequency Control
Phase Lock Loop (PLL) synthesizer.
Frequency Tolerance
0.005%
Frequency Stability
0.001%
Operating Temperature Range
-30° C to + 50° C
Microphone
Plug-in dynamic; with push-to-talk
switch and coiled cord.
switch and coiled cord.
Input Voltage
13.8V DC nominal, 15.9V max., 11.7V
min. (positive or negative ground).
min. (positive or negative ground).
Current Drain
Transmit: AM full mod., 2.2A. SSB 12
watts PEP output, 2A.
Receive: Squelched, 0.25A
Maximum audio output, 0.6A.
watts PEP output, 2A.
Receive: Squelched, 0.25A
Maximum audio output, 0.6A.
Size
2 3/8”(H) x 7 7/8”(W) x 9 1/4”(D).
Weight
5 lbs.
Antenna Conductor
UHF, S0239.
Semiconductors
3 field effect transistors, 45 transistors,
63 diodes, 6 integrated circuits, 1 two
color light emitting diode.
63 diodes, 6 integrated circuits, 1 two
color light emitting diode.
Meter (3-in-1)
Illuminated; indicates relative output
power, received signal strength,
and SWR.
power, received signal strength,
and SWR.
TRANSMITTER
Power Output
AM, 4 watts.
SSB, 12 watts, PEP.
SSB, 12 watts, PEP.
Modulation
High-and low-level Class B, Amplitude
Modulation.
Modulation.
Intermodulation Distortion
SSB: 3rd order, more than -25 dB.
5th order, more than -35 dB.
5th order, more than -35 dB.
SSB Carrier Suppression
55 dB.
Unwanted Sideband
50 dB.
Frequency Response
AM and SSB; 300 to 2500 Hz.
Output Impedance
50 ohms, unbalanced
Output Indicators
Meter shows relative RF output power
and SWR. Transmit LED glows red when
transmitter is in operation.
and SWR. Transmit LED glows red when
transmitter is in operation.
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