Related Manuals for LNR Currahee MTR3B-V4
Summary of Contents for LNR Currahee MTR3B-V4
- Page 1 MTR3B-V4 “Currahee” Version Mountain Topper “The original Miniature QRP Transceiver” Operating Manual LNR Precision Rev. 5/7/2025...
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Page 2: Table Of Contents
TABLE OF CONTENTS Introduction ...........................4 Features ............................4 MTR3B-V4 Display, Controls, and Jacks ..................5 Front and Top Panels ......................5 Color Display .........................7 Operation ..........................8 Power ON / OFF ........................8 Band Selection ........................8 Frequency Selection ......................9 Frequency Memory ......................11 Receiver Incremental Tuning (RIT) ..................13 Direct Frequency Entry (DFE) ..................... - Page 3 Morse Enunciation ....................... 22 CAL ............................. 22 EE ERASE........................... 23 Specifications .......................... 23 Revision History ........................24 Contact Information ......................... 25...
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Page 4: Introduction
High Frequency (HF) CW transceiver. The MTR3B-V4 is the latest of the “Mountain Topper” series of rugged, lightweight, miniature CW transceivers by LNR Precision - the manufacturer of “The original Miniature QRP Transceiver”. It is an all-new design by Steve Weber (KD1JV) which has significant updates, but uses the same ultra lightweight, small form factor that was loved about the original. -
Page 5: Mtr3B-V4 Display, Controls, And Jacks
MTR3B-V4 DISPLAY, CONTROLS, AND JACKS The following sections describe the display, controls, and jacks, used to setup and operate the MTR3B-V4. Front and Top Panels Figure (1) shows the layout of the front panel of the MTR3B-V4 and figure (2) shows the top panel. - Page 6 – The Antenna Jack is a BNC female connector for connection of an HF Antenna Jack antenna with a nominal impedance of 50 Ohms. – The DC Power Jack is a 5.5mm X 2.1mm coaxial connector. The DC Power Jack center pin is positive (+).
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Page 7: Color Display
– The Power Switch turns the MTR3B-V4 On and Off. Power Switch Color Display Figure (3) shows the layout of the MTR3B-V4 Color Display. Lines 1 and 2 always show the same information. The information shown on lines 3 – 5 depend upon the current function. The bottom of figure (3) shows an example of a menu on lines 4 and 5 and the menu buttons below. -
Page 8: Operation
– The Step Cursor shows which frequency digit the Tune Up [ ] / Tune Step Cursor Down [ ] buttons will change. – Line 3 of the Color Display RIT Frequency Offset or Frequency Memory Contents shows either the RIT Frequency Offset or Frequency Memory Contents. –... -
Page 9: Frequency Selection
Figure 4. Band Switch Operation. Band Switch Rules: 1. Always adjust Band Switches from top to bottom. 2. All three Band Switches must be switched to the same band (positioned along the vertical line corresponding to the selected band). 3. When selecting the 20M band (Band Switches in the middle position), start with all three Band Switches to the left (40M) or right (15M) and then slide them to the middle position going from top to bottom. - Page 10 Figure 5. Changing Frequency. Fast Frequency Step Tuning Fast Frequency Step Tuning is indicated by the Step Cursor positioned under the digit to the right of the decimal point (100 Hz digit) of the Frequency Display. To enter Fast Frequency Step Tuning: •...
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Page 11: Frequency Memory
Really Fast Frequency Step Tuning Really Fast Frequency Step Tuning is indicated by the Step Cursor positioned under the digit to the left of the decimal point (1 KHz digit) of the Frequency Display. To enter Really Fast Frequency Step Tuning: •... - Page 12 3. Tap the TUNE Down [ ] button to go to the next lower Memory Location. If the Memory Location is “1”, tapping the TUNE Down [ ] button has no effect. Store Frequency Memory The Store Memory function is used to enter and save a frequency into a specified memory location for future use, see example in figure (6).
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Page 13: Receiver Incremental Tuning (Rit)
Figure 7. Load Frequency from Memory. 4. To load a frequency from the selected memory location, tap the Enter “EN” ([Fn]) button. Line 2 of the Color Display will show the new operating frequency. Note: If the memory location is empty, the operating frequency will not change. 5. -
Page 14: Direct Frequency Entry (Dfe)
Direct Frequency Entry (DFE) The Direct Frequency Entry (DFE) function allows you to directly enter a frequency via the Morse Code keyer paddle, which could be faster than using the tuning buttons. Firmware Version 1.08 or higher is required for DFE functionality. 1. -
Page 15: Message Memory
Message Memory Store Message Memory The Message Memory function is used to store up to 62 Morse Code characters in each of the three memory locations. See figure (9) for the Message Memory menu options. 1. To enter the Message Memory function, press and hold the Function [Fn] button until the function “K-MEM”... -
Page 16: Keyer Speed
6. If you make a mistake, tap the “X” ([RIT]) button to restart entering the message. An acknowledgement beep will be heard. 7. When you have finished keying in the message, tap the “CK” ([Fn]) button to check the message. 8. -
Page 17: Tune Mode
2. Tap the TUNE Up [ ] button or press the Dash paddle to increase the Code speed. A beep sounds when the speed is changed, and it will turn green. 3. Tap the TUNE Down [ ] button or press the Dot paddle to decrease the Code speed. A beep sounds when the speed is changed. -
Page 18: Paddle Reverse
Figure 11. Tune Mode Display. Paddle Reverse The Paddle Reverse function enables reversal of the Keyer paddle normal Dot / Dash assignment. This is needed because some other transceivers use the opposite wiring of the keyer jack. This feature requires at least Version 1.12c. 1. -
Page 19: Straight Key
Straight Key The Straight Key mode disables the built-in electronic keyer and enables use of a hand key. 1. Press and hold the Function ([Fn]) button until “CS” appears on Line 4 of the Color Display. 2. Tap the [RIT] button. The Code Speed value will be replaced with “SK” on Line 5 of the Color Display. -
Page 20: Audio Volume Adjustment
4. Press the Dash paddle to pause beacon replay. 5. Press the Dot paddle to stop beacon replay. Audio Volume Adjustment Normal audio volume adjustment on the MTR3B-V4 is accomplished using an inline analog volume control on a headphone or the volume control of an external amplified speaker. The maximum audio output is adjustable using the volume control, marked “VOL”, on the front panel of the MTR3B-V4 above the Color Display, see figure (1). -
Page 21: Side Tone Volume
Figure 14. Side Tone Adjustment. Side Tone Volume A trimmer resistor is accessed through a hole in the battery/jack board inside the case. Start by unscrewing the side screws of the enclosure and removing the black enclosure bottom. Locate the battery/jack board and notice the hole which reveals this trimmer resistor. Carefully rotate the trimmer resistor with a small non-conductive Phillips screwdriver to adjust the side tone volume level. -
Page 22: Morse Enunciation
The Calibration function is used to calibrate the transceiver’s local oscillator . This function is accessed by pressing and holding the [RIT] button until “CAL” is display on Line 4 of the Color Display. It is not intended for field operator use. Contact LNR Precision for technical support. -
Page 23: Ee Erase
This function is accessed by pressing and holding the [RIT] button until “EE ERASE” is display the device. on Line 4 of the Color Display. It is not intended for field operator use. Contact LNR Precision for technical support. SPECIFICATIONS •... -
Page 24: Revision History
REVISION HISTORY Version Number Criticality Description 1.06 Baseline 1. Changed certain Colors on LCD to prevent washout. 2. Corrected CW Messaging while in RIT mode. 3. Hardware design change and new jackboard. 4. Etched aluminum MTR3B V4 “Currahee” star badge. 5. -
Page 25: Contact Information
CONTACT INFORMATION LNR Precision will perform Firmware updates free of charge for customers wishing to update their unit. If you wish to receive an update of your unit, please write a note indicating UPDATE and include your name, callsign, phone number and RETURN MAILING ADDRESS and send radio LNR Precision, Inc.
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