Elecraft XG2 Manual - Manual (Page 5)

5
Applications
A 50-µV signal is a commonly-accepted level for "S9," and a 1-µV signal is often used to
measure signal-to-noise ratio to evaluate the sensitivity of a receiver (see procedures starting on
next page). The XG2 can be used to evaluate a new receiver, check the condition of an old
receiver, or check a receiver after exposure to lightning or other traumatic events. A homebrew
receiver’s sensitivity is easily measured, and design choices can be evaluated to improve the
design. Since the XG2 is self-powered, lightweight and small in size, it's an ideal tool to take to a
flea market to evaluate used gear.
Receiver Sensitivity Testing (Using 1 µV Signal)
The XG2 can be used to test absolute receiver sensitivity, providing a means of comparing
various receivers or transceivers. The instructions below apply to any type of receiver or
transceiver, but we've included settings for the Elecraft K1 and K2.
1. If you're testing a transceiver, turn its power output level to minimum as a precaution, and
disconnect the key or keyer and mic. If you're using an ATU, put it into bypass mode (CAL or
CALS on Elecraft tuners).
2. Connect the XG2 to the antenna jack on the receiver (or transceiver). You can connect the XG2
directly to receiver or transceiver using a suitable adapter, such as our model BNC-MM .
NOTE: Keep your hands and other objects away from the XG2 during measurements, as this
may affect the output signal level, especially at the 1-microvolt setting.
3. Turn AGC OFF if possible. (K2, hold PRE+AGC switches. K1, use AGC menu entry.)
4. Set RF GAIN to maximum.
5. Turn off the attenuator.
6. Turn on the preamp. NOTE: Preamp OFF tests may also be useful.
7. Select CW mode, narrow passband if available ("CW-N" on some rigs).
8. If possible, set the filter bandwidth for about 500 Hz, the standard for lab receiver tests. (K2,
use FLx = 0.70, which corresponds to about 500 Hz. For the K1, use FLx = 500.)
9. Turn off, bypass, or widen the audio filter if applicable. (K2: see KAF2 or KDSP2 manual.)
10. Connect the probes of a digital multimeter (DMM) across the speaker terminals. Set the
DMM for 2 or 3 volts AC (or RMS) full-scale. (K2: Connect the DMM across the internal
speaker or the external speaker jack. If you use the headphone jack, don't plug in headphones at