Advertisement

MFJ cub QRP CW Transceiver
Operation Manual

INTRODUCTION

Congratulations on purchasing the MFJ cub Transceiver.
The cub takes
advantage of SMD technology to achieve big-radio performance in a pocket-
sized package.
Whether you're taking a 10-minute DX break from the
computer, or backpacking in the mountains, the cub is a great way to put the
magic back into ham radio. Here are a few of the features we think you'll
appreciate:
Hot Receiver: Pulls in weak QRP signals.
Low Noise: Virtually no noise contribution from receiver electronics.
Sharp Passband: Ladder filter and shaped audio reject unwanted QRM and
QRN.
Differential-Mode AGC: Audio output holds steady over 80-dB signal range.
Robust AF Output: 100 mW AF amp drives headphones and speakers with
ease.
Adjustable Transmitter: Power output continuously variable for QRP.
Full QSK: Seamless electronic switching for smooth break-in.
Natural Sidetone: Receiver monitors actual on-air signal.
Shaped Keying: Controlled envelope for click-free keying.
Custom Set-up: Transmit offset and receiver passband both user adjustable.
Low Power Drain: Runs from any lightweight regulated power source.
Truly Portable: Set up anywhere and tuck out of the way when not in use.
Simple to Use: Off/on switch, volume control, and tuning knob--that's it!
Attractive: Rugged aluminum case looks good, and it's built to last.
Ergonomic Layout: Controls conveniently positioned.
1

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Cub and is the answer not in the manual?

Questions and answers

Summary of Contents for MFJ Cub

  • Page 1 Whether you're taking a 10-minute DX break from the computer, or backpacking in the mountains, the cub is a great way to put the magic back into ham radio. Here are a few of the features we think you'll appreciate: Hot Receiver: Pulls in weak QRP signals.
  • Page 2 MFJ cub QRP CW Transceiver Operation Manual TYPICAL SPECIFICATIONS Cub models are available for six popular QRP bands. Typical performance for each is shown in the following table: Tuning IF Freq -6dB Power Spurs Model Selectivity Selectivity 9315 <.3uV 9317 8.06...
  • Page 3 8. Power Jack: Accepts 5.5 mm OD, 2.1 mm ID coaxial plug, (+) to center. QUICK-START OPERATING INSTRUCTIONS Power Sources: The cub requires a regulated 12-14 VDC source capable of delivering 400 mA. Power connection requires a 5.5 mm x 2.1 mm coaxial plug (use Radio Shack 274-1567).
  • Page 4 Stereo Plug Mono Plug Antennas: The cub is designed to work with any efficient 50 ohm antenna exhibiting a VSWR of 2:1 or less. Suggested dipole lengths are shown in the following diagram, along with data for adding a simple coaxial choke-type...
  • Page 5 MFJ cub QRP CW Transceiver Operation Manual Antenna Connection: The cub uses either a RCA antenna jack or the optional chassis-mounted BNC connector (mounting hole provided). For a direct transition from RCA to standard UHF (PL-238) connectors, use a Radio Shack scanner-adapter plug RS278-208.
  • Page 6 QRP DX Operating Tips: Competing with more powerful stations to capture QSLs from rare DX prefixes requires patience and good operating skills. Here are 10 tricks-of-the-QRP-trade you can use with your cub to land the tough ones! 1. Hunt and pounce! There's never a pileup if you're the first one there.
  • Page 7 MFJ cub QRP CW Transceiver Operation Manual 10. Pay attention to DX forecasts. When the band is hot, power differences matter less. CIRCUIT DESCRIPTION In receive, Chebechev filter L1-L2 preselects incoming signals. U2 converts signals to the IF using its internal LO as a varactor-tuned VFO. IF amp Q1 drives ladder filter Y1-Y3.
  • Page 8 IN CASE OF DIFFICULTY If you experience a problem with your cub, look through the checklist below to determine if it's something simple you can fix yourself. If that fails to resolve the problem, you may contact MFJ Technical Service at 662-323-0549 or the MFJ Factory at 662-323-5869.
  • Page 9 MFJ cub QRP CW Transceiver Operation Manual MFJ CUB ALIGNMENT AND SERVICE NOTES Alignment Control Function 1. BFO Trim (set for 600-Hz LSB passband center) 2. VFO Cal (set for desired CW band segment) 3. Rx BPF (tune for maximum sensitivity) 4.
  • Page 10 MFJ cub QRP CW Transceiver Operation Manual IC Voltages 13.8 13.8 Component Pinout: 8 7 6 5 SOT-23 Transistor Package SO-8 2N5109 Style 6 IC Package Style 10 Style 21 1N914 (Top) (case) N.C. 2N7002 J310 2N3904 1 2 3 4...
  • Page 11 MFJ cub QRP CW Transceiver Operation Manual PARTS PLACEMENT...
  • Page 12 MFJ cub QRP CW Transceiver Operation Manual SCHEMATIC...
  • Page 13 MFJ cub QRP CW Transceiver Operation Manual NOTES...

This manual is also suitable for:

Cub 9315Cub 9317Cub 9320Cub 9330Cub 9340Cub 9380

Table of Contents