    
Tech808
Moderator
Username: Tech808
Post Number: 17594
Registered: 8-2002
| | Posted on Tuesday, April 20, 2010 - 9:22 am: | 
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MAGNUM 257HP
AM/FM/SSB
10 METER MOBILE AMATEUR TRANSCEIVER
COPPER PART #P03-01002
Magnum 257HP 10 Meter Mobile
Non - Technical - User
Review.
By
Lon ~ Tech808 ~ N9CEF
With The
MAGNUM
Full Sized
Hand Microphone
w/ Up & Down
Channel ~ Frequency
Control Button's.
Which make's it a pleasure to use as a Base Radio without having to manuaually change channel's with the radio control knobs.
and the
Powerband RFX75 RF Driver
Factory Installed.
The RFX75 is a Brand RF section with, RF Driver and Transistor's for the
Magnum 10 Meter Amateur
Transceivers
and can be installed on
Other
Radio's ~Transceivers.
Copper Part# P03-00001
Powerband RFX75 RF Driver
Features:
Microprosser Controlled
Full 10 Meter Coverage
ERF 2030 Mosfet Power
Modes of Operation: AM~FM~LSB~USB
FULL 1 Year LTD MFG Warranty
FULL SIZE Magnum Microphone with UP~DN Channel / Frequency control button's. 
Variable RF/Output Power
5 ~ Digit LCD Frequency Display
Frequency Scanning
Night Illumination / Frequency Display ~ Control Knobs ~ Color BLUE
Automatic Call Frequency
Actual Dimensions:
2" ~ Height
6" ~ Width
10" ~ Length w/Control Knobs
Note!
Measured from outer Amp Fins on rear to front of Control Knobs.
RF Power Output: 80 Watts
Schematics:
VERY NICE!
Easy to read Schematics:
Size: 16-1/2" Width x 11-3/4" Depth
15' Heavy Duty ~ 10 Gauge TP Quick Connect Power Cord with a 15 AMP Automotive type blade fuse, which will allow you to connect the radio directly to the car batery and still allow you a Quich disconnect for removing the radio if if you use your radio for security and / or Base & Mobile use like a lot of us do.
Front Panel Controls:
1 ~ Power On\Off and Gain Control
2 ~ Microphone Input
3 ~ RF Gain Control
4 ~ Microphone Gain Control
IMPORTANT NOTE!
Operating some of the features in 5 through 10 requirethe use of the function control. To activate the function control, momentarily Push FUNC button, and the FUNC prompt will be displayed in the UPPER-LEFT HAND corner of the LCD. Push the control again to DEACTIVATE the function control.
5 ~ STEP \ NB \ Memory Channel 1 Step
Noise Blanker
6 ~ LCR \ RPT \ MEMORY CHANNEL
7 ~ CALL \ MEMORY CHANNEL 2 CALL
8 ~ MODE \ T. LOW \ MEMORY CHANNEL 5
9 ~ SCAN \ SHIFT \ / MEMORY CHANNEL 3 \ SCAN
10 ~ MEMORY SAVE \ MEMORY LOAD
11 ~ CLAR \ FUNC
12 ~ FREQUENCY
13 ~ PWR
14 ~ SQ
Other Features:
Programing Tone
Memory Back Up
Accessories:
*Mobile Mounting Bracket w/Kobs
* Full Size Microphone w / Up-Dn Control Buttons
* 15' ~ 10 Gauge Power Cord w/TP connector
*Owners Manual
FREQUENCY MODIFICATION / EXPANSION:
Step #1: Make sure Magnun 257HP is turned off and disconnected from power sourcel.
Step #2: Remove Speaker Side Cover & disconnect the Black & White Speaker Wire from the Rear of the Main PCB Board.
Step #3: Locate the small 1-1/2" x 3/4" CPU Reset Board located near the Front RIGHT panel of the radio located behind the Microphone Connector.
Step #4: Remove the single screw holding the small board to the radio franme.
Step #5: On the CPU Reset Board there are 4 jumper positions (CON-1 / CON-2 / CON-3 / CON-4).
Each jumper position will provide a different frequency range and configuration.
From the list below, select the desired frequency range and configuration, and move the jumper shunt to the corresponding CON #.
CON1: ~ 10 Meter Only (28.000 - 29.699 MHz)
*Default mode
*All functions operate normally
CON2: ~ 10 Meter & Expanded Mode
*At turn on, the radio defaults to 10 Meter mode.
*For Expanded mode, press FUNC and then press CALL for 3 seconds.
*To return to 10 Meter mode, repeat above steps.
for information on Expanded mode operation, see CON3
CON3: ~ Expanded Mode Only (25.165 - 29.699 MHz)
In the Expanded mode, the frequency range is divided into 10 Bands of 40 Channels each.
The Bands are shown on LCD display by letters (A through J) - Band E is regular 40 channel CB. To switch bands, press the CALL button (do not hold down for 3 seconds).
In the Expanded mode, either the frequency or channel can be displayed on the LCD. To switch between freqency display and channel display, press the FUNC button and then press the CALL button (do not hold down for 3 seconds).
On the channel display, the small number (0 - 9) to the right of the Band letter is the 1 kHz frequency display.
Example: If the frequency is 27.405, then the channel display will indicate 40 E5. (40) being the channel, (E) being the Band, and (5) being the 1 kHz position of 27.405.
Note!
In the Expanded Mode, the RPT and SHIFT functions Will Not Operate.
CON4: ~ 40 Channel CB Only (26.965 - 27.405 MHz)
(Only operates on the regular 40 CB channels.)
Step #6 After selecting the desired frequency range and configuration, press the CPU Reset Switch (SW1) for 5 - 10 seconds.
Step #7 Reassemble the radio, turn on and test.
NOTE!
MAGNUM 257HP Owners Manual
Addendum
AM ~ Transmitter audio level adjustment.
The AM transmitter's audio level is adjusted by VR4. Turning the VR clockwise increases the audio level.
TRANSMITTER Specifications
Power Output:
AM: 1~15 watts
SSB: 65~75 watts
FM: 1 watt minimum / 15 watts maximum
RF Complement:
Driver Stages: 1xerf2030 MOSFET driving 1 ERF 2030 Final stage: 1 ERF7530 MOSFET.
Test Setup:
50amp regulated supply @ 14vdc. Bird43 Thruline w/4300-400 Peak Power conversion Kit. 25~60MHZ, 100w element.
PWR from panel control Page 10
AM/FM operation:
Variable power control raise and lowers carrier only.
Minimum carrier full CW 15 watts AM.
SSB Operation:
Set the PWR control to FULL CW (clockwise) position.
For reduced power or QRP operation reduce the mike gain control by rotating CCW until the desired power is obtained.
My Personal Test ~ User Comment's
The MAGNUM 257 has alway's been a very good small framed radio, but now the 2nd generation or the BIG BROTHER the MAGNUM 257HP is now a GREAT RADIO! 
The addition of the Full Sized MAGNUM Hand Microphone with Up ~ Dn channel control button's is a GREAT addition to this already Great radio from Magnum International.
It has a very good easy to understand Owner’s Manual for the 1st time Radio Operator or the more experienced operator.
In conclusion:
I would personally rate the MAGNUM 257HP a “10+”
I would also like to say Thank You! to Shirley ~ 808xyl and my daughter Tesa ~ Tddtime who drove down from Greenbay WI. for a visit and both helped me with testing this radio as a Base radio and in testing it in Mobile use.
Lon~Tech808
N9CEF
CEF#808
Radio Enthusiast!
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