Noble Radio NR-4SC 4 Meter SSB/CW Transceiver

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The NR-4SC is a simple to use 10 Watt (minimum) 4 Meter SSB/CW transceiver. The radio operates USB and CW.

The NR-4SC uses a single conversion design with an IF frequency of 10.7 MHz. Front end band pass filters limit out of band signals into the RF Preamp stage.

A double balanced diode ring mixer provides good strong signal handling capability. There are two 8 pole crystal filters following the mixer which are designed for 3.0 kHz and 500 Hz -6dB bandwidths. The 3 kHz filter allows for good SSB voice fidelity while the 500 Hz filter provides good adjacent channel rejection on CW. Either filter can be selected in both modes.

Two IF amplifier stages and fast attack AGC provide good re-ceiver sensitivity while leveling the audio output on strong sig-nals. AGC action starts at approximately a -120 dBm input signal level.

The local oscillator is derived from a DDS/PLL circuit providing a high degree of stability and low noise.

A high stability 107.374 MHz reference oscillator is used for all local oscillator generation. The high frequency provides low DDS spurious out-put.

The transceiver offers a 10.7MHz IF out on the back panel for connection to an SDR so it may be used with a PC for a Spectral Display.

Other features of the NR-4SC include RIT (Receiver Incremental Tuning) and SPLIT mode functions as well as a built in Iambic Keyer for CW. The AGC rate has a FAST and SLOW speed to suit operator preference.

Specifications

  1. SSB/CW
  2. 10 Watt output power
  3. Built in Iambic keyer
  4. Analog S-meter, not a bargraph.
  5. RIT
  6. SPLIT
  7. Variable Speed Tuning VST
  8. Wide and Narrow filter
  9. Fast and Slow selectable AGC
  10. Output to key an external Amplifier
  11. Can be switched for QSK and Non QSK compatible Amps
  12. Simultaneous display of RX and TX frequencies
  13. 13.8VDC at 4 Amps TX current
  14. 650 mA RX current
  15. Built in loudspeaker
  16. Audio output .6 Watt
  17. 10.7 MHz IF output
  18. RX Sensitivity -130dbm MDS
  19. IF rejection greater than 100db
  20. Blocking dynamic range 107db
  21. Third Order Dynamic Range = 96db (IP3 = +14dBm)
  22. 2nd Order Dynamic Range 87db (IP2 = +44dBm)
  23. TX spurious is better than - 55dBc which meets CE ETSI EN301 783-1 standard