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Username: Tech808

Post Number: 6384
Registered: 8-2002

Posted on Wednesday, July 20, 2005 - 12:21 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)




Complete Specifications, Modifications, and Non - Technical Review.


Lon ~ Tech808 ~ N9OSN ~ CEF808

General Specifications
Emission ModesAM/FM
Antenna Impedance50 ohms
Antenna ConnectorStandard SO-239 type
MicrophoneCobra M73SL (Plug-in dynamic with Press-To-Talk switch and coiled cord
Frequency Range Stock28.0 to 29.7 MHz
Frequency Range (after conversion)26.065 to 29.695
Frequency ControlPhase-Lock Loop (PLL) Synthesizer
Frequency Stability0.005%
Operating Temperature Range-22 F to 122 F (-6 C to +50 C)
Input Voltage13.8 V DC nominal / 15.9V max Positive or Negative Ground
Currant DrainTransmit: 3.0A / Receive (squelched) 0.5A / Receive (maximum audio output) 1/2A
Dimensions / Size2-3/8 (H) x 7-7/8 (W) x 9-3/4 (D)
Meter(3 in 1)Illuminated-indicates relative output power / received signal strength and SWR
Built in Speaker4 watts

Transmitter Specifications
Power OutputLow ~ 4 watts / High ~ 15 Watts
Final TransistorsMitsubishi RD16HHF1 Silicon Mos Fet (x2) Rated at 16 watts at 30 MHz
Frequency Tolerance500Hz
Frequency Response300 to 3000 Hz
Transmit Distortion2%
Spurious Harmonic Emission-65dB
Output IndicatorsMeter shows relative RF output power and SWR. Transmit LED glows red when transmitter is in operation
Antenna Warning LEDGlows red when SWR is greater than 3.0

Receiver Specifications
SensitivityAM:0.5 µV for 10dB S/N, FM:025 µV for 12 dB S/N
Audio Frequency Response300 to 3000 Hz
Maximum Signal to Noise Ratio45dB
Image Rejection75 dB
Adjacent Channel Rejection65 dB
RF Gain Control (AGC)40 dB - adjustable for optimum signal rejection
SquelchAdjustable - threshold less than 0.5µV
Automatic Noise Limiter (ANL)Switchable
Noise Blanker (NB)Switchable
Receive IndicatorsMeter shows relative signal strength / Receive LED glows green when receiving a signal.

PA System

Power Output4 watts into PA speaker
Speaker for PA (Not Supplied)8 ohms

External Speaker
Power Output4 watts into a PA speaker
External Speaker(Not Supplied)8 ohms

Standard Features / Controls / Connectors on Radio.

Front Panel

* Analog Meter
* PA/AM/FM Control Selector Control
* Band A/B/C/D/ Slector Control
* RF Power Hi/Low Switch
* +10kHz / Off Switch
* NB/ANL Off Switch
* Dual 7 Segment Frequency Display
* Microphone Connector (Standard 4 Pin)
* Off/On Volume Control (Center Knob) / Squelch
(Outer Ring)
* Microphone Gain (Center Knob) / RF Gain (Outer Ring)
* Talk Back (Center Knob) / Echo (Outer Ring)
* Dim (Center Knob) NightWatch & Meter / Not Channel Display / SWR Cal (Outer Ring)
* Antenna Warning Indicator
* Frequency Selector

Back Panel

* External Speaker Connector
* 2 Wire T-Fitting Power Cord Connector Wire
(No Standard Plug in Type Connector)
* SO-239 / Antenna Connector
* Frequency Counter Connector (FC390 / FC347 Type)


The Cobra 150 GTL DX is programmed for the 10 Meter Amateur Band out of the box, and covers a range of 28.000 - 29.700 MHz.

The frequency range can be extended for Export Use in 4 Band segments each containing 80 Channels except Band D which will contain 76 Channels.

Stock 10 Meter Frequency Coverage:

This mode is pre-set to 4 Bands with coverage of the 10 Meter Band from 28.000 MHz to 29.700 MHz.

A-Band ~ Channels 1 thru 49 = 28.000 thru 28.495

B-Band ~ Channels 50 thru 99 = 28.500 thru 28.995

C-Band Channels 00 thru 49 = 29.000 thru 29.495

D-Band ~ Channels 50 thru 70 = 29.500 thru 29.700

Export Conversion

Export / Converted Frequency Coverage:

Channel Display:

The Channel Display has visual indicators located on each side of the Channel Number/Display to indicate the Band Segments and the "A / Alpha" Channels.

The Band Segment Dot is displayed to the LEFT of the Channel Display and the A / Alpha Channel Dot is displayed to the RIGHT of the Channel Display and will look like this: .20.

This mode has 8 Bands divided into 4 Bands with switch positions on the radio marked A/B/C/D

Each band has two (2) 45 channel frequency blocks for each letter A/B/C/D

For example: Band "A" would start on the lower frequency segment 1~40 and then continue to the next segment when channel 40 is passed.

The channel display will show a small Red (.) dot on the Left Side of the Channel Display indicating that the radio is in the UPPER SEGMENT of the 2 Bands.

The Channel Display will look like this ~ .20

The Cobra 150 GTL DX also has "Continuous" coverage of each Band by NOT skipping the "A" channels between channel 3, 7, 11, 15, and 19.

As you reach Channel 3 the next Channel up will display the number 3 again with a small dot on the RIGHT SIDE of the 3.

The Channel Display will look like this: 3.

This will represent Channel: 3A

After Conversion Frequency Coverage:

A-Band- 26.065 - 26.505
.A-Band- 26.515 - 26.955

B-Band- 26.965 - 27.405
.B-Band- 27.415 - 27.855

C-Band- 27.865 - 28.305
.C-Band- 28.315 - 28.755

D-Band- 28.765 - 29.295
.D-Band-29.305 - 29.695

Microphone Wiring

Pin #1 ~ Ground
Pin #2 ~ Microphone Audio
Pin #3 ~ Transmit
Pin #4 ~ Receive


I have added the Tune-Up Information that I have to the Copper Modification List.

At the time of my writing this Review I know of No Other Modifications for this radio.

Should any Modifications or Tips become avialiable I will keep everyone updated.



* Limited 2 Year Factory Warranty

* 2 ~ Mitsubishi RD16HHF1 Silicon MOSFET Power Transistors: Rated: Pout>16W, Gp>16dB @Vdd=12.5V,f=30MHz (Replaces older style 1969 finals.)

* Power in bench testing with power switch set to HI produced a 15 watt dead key swinging to 50 watts PEP.

* Toshiba 80 Pin TMP87PP21DF Microprocessor.

* Super Heavy Duty 10 gauge Power Cord with Automotive 10 Amp large blade type fuse.

* 2-1/8" x 3" x 7-3/4" Single Piece Solid Aluminum Heat Sink.

* SMT Components.

* PFM-0089A-BB Mother Board

* External Frequency Counter Connector located on back panel (ie: FC347 / FC-390 Type) Located under SO-239 conector.

* Style Cobra M73SL Microphone (Stainless Grill)

* 1/4" Larger / Taller Analog Meter


* This radio should be called an 8 Band Radio as you will have 8 Bands/Groups of channels after Conversion.

You will have 2 Bands/Groups of channels on each of the 4 Bands A thru D.

* No Variable Power Control just a High/Low Power Switch.


While this Cobra 150 GTL DX looks larger than the older cobras it is the same size as only the SWR/Watt Meter is slightly larger with new style control knobs.

I would personally suggest adding a FC347 or FC390 Frequency Counter as the Frequencies / Channels do not match the standard 3/6/8/10 or 12 band Frequency/Channel Charts.

Respectfully Submitted,