Wednesday, 29 July 2015

Noble NR-4SC 70Mhz USB/CW Transciever

The NR-4SC is a simple to use 15 Watt (nominal) 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
receiver sensitivity while levelling the audio output on
strong signals. 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 output. 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.

2) 15 Watt output power
3) Built in Iambic keyer
4) Analogue S-meter, not a bar graph.
5) RIT
7) Variable Speed Tuning (VST)
8) Wide and Narrow Crystal filter
9) Fast and Slow selectable AGC
10) Output to key an external Amplifier
11) Can be switched for QSK and Non QSK compatible
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 standards
24) 10.625 in W (27 cm) x 11.25 in D (28.6 cm) x 5.375 in H
(13.7 cm) – This excludes the height of the feet and the
knobs and connectors on the 18 front and rear panels.
25) Weight - Approximately 11 lbs (5 Kg)

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