[R-390] Z. Receiver Signal to Noise Test

[Flowertime01 at wmconnect.com]

Z. Receiver Signal to Noise Test

___ 01 Install a 600 ohm resistor on the line level output.
___ 02 Turn the receiver on and allow it to warm up for 1 hour
___ 03 Turn the signal generator on and allow it to warm up for 1 hour
___ 04 Set the R390 or R390A Function switch to "MGC
___ 05 Set the R390 or R390A Bandwidth to 2kc
___ 06 Set the R390 or R390A RF gain full CW (Clock Wise)
___ 07 Set the R390 or R390A AF line gain full CW
___ 08 Set the R390 or R390A AF local gain full CW
___ 09 Set the R390 or R390A BFO off
___ 10 Connect the generator to the receiver's balanced antenna input
___ 11 Place a meter and 600 ohm load on the Local Audio output.
___ 12 Set the receiver and generator to the same frequency of choice
___ 13 Use the RF deck alignment point frequencies
___ 14 Conduct the test while performing RF deck alignments
___ 15 Use 550, 950, 1,100, 1,200, 1,900, 2,250, 3,800, 4,400,
___ 16 Use 7,250, 7,600, 8,800, 15,200, 17,600 30,400
___ 17 Rock the generator for a peak in to the band pass
___ 18 Set the initial generator output to 10uv
___ 19 Set the generator modulation level to at 30% 400 Hz or 1 KHz
___ 20 Use the Ant Trim to peak the receiver
___ 21 Set the Line Meter range switch to + 10
___ 22 Reduce the RF output level of the generator to 0 VU
___ 23 This should also be 450 milliwatts on the Local Audio
___ 24 This value is the 20 DB S/N + N receiver level at this frequency
___ 25 Set the signal generator to CW
___ 26 The Meter on the Local Level should drop 20 DB
___ 27 The Line Meter should drop to -20 DB
___ 28 This is the relative receiver noise floor level at this frequency
___ 29 It signal generator RF level should be less than 3 micro volts
___ 30 The official specifications of the receiver call for 3 micro volts
___ 31 Record the frequency and the output of the generator in micro volts
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